International Immunology

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International Immunology, Vol. 12, No. 4, 573-580, April 2000
© 2000 Japanese Society for Immunology

A BASH/SLP-76-related adaptor protein MIST/Clnk involved in IgE receptor-mediated mast cell degranulation

Ryo Goitsuka^1,2, Hideki Kanazashi¹, Hiroki Sasanuma¹, Yu-ichi Fujimura¹, Yuri Hidaka¹, Akiko Tatsuno¹, Chisei Ra³, Katsuhiko Hayashi¹ and Daisuke Kitamura¹

¹ Division of Molecular Biology, Research Institute for Biological Sciences, Science University of Tokyo, 2669 Yamazaki, Noda, Chiba 278, Japan
² Inheritance and Variation Group, PRESTO, Japan Science and Technology Corp., 2669 Yamazaki, Noda, Chiba 278, Japan
³ Division of Molecular Biology, Allergy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113, Japan

Correspondence to: R. Goitsuka, Division of Molecular Biology, Research Institute for Biological Sciences, Science University of Tokyo, 2669 Yamazaki, Noda, Chiba 278, Japan

	Abstract

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Cross-linking of the high-affinity IgE receptor (FcRI) on mast cells by IgE–antigen complex triggers signal transduction cascades leading to the release of inflammatory mediators and production of cytokines, which are critical for the development of allergic reactions. We have identified a novel member of the BASH/SLP-76 immunoreceptor-coupled adaptor family expressed in mast cells, termed MIST (for mast cell immunoreceptor signal transducer), which has later been found to be identical to a recently reported cytokine-dependent hemopoietic cell linker, Clnk. Upon FcRI cross-linking, MIST/Clnk is tyrosine phosphorylated and associates with signaling proteins, phospholipase C, Vav, Grb2 and linker for activation of T cells (LAT). Overexpression of a mutant form of MIST/Clnk inhibited FcRI-mediated degranulation, increase in intracellular Ca²⁺, NF-AT activation and phosphorylation of LAT. As a crucial signaling component for FcRI-induced mast cell degranulation, MIST/Clnk might serve as a target for anti-allergic therapy.

Keywords: FcRI, RBL, signal transduction

	Introduction

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Mast cells play a pivotal role in the development of IgE-mediated allergic reactions through releasing stored and newly synthesized inflammatory mediators following cross-linking of the high-affinity IgE receptor (FcRI) on the cell surface (1). FcRI belongs to a family of multi-subunit hematopoietic cell receptors, including the TCR and B cell antigen receptor (BCR). All the members of this family lack an intrinsic protein tyrosine kinase (PTK) activity, but possess cytoplasmic component-containing immunoreceptor tyrosine-based activation motifs for initiating the phosphorylation-mediated signaling cascade (2,3). In the signaling pathway from these immunoreceptors to the nucleus, PTKs belonging to the Src, Syk/Zap70 and Btk/Tec families are activated, and in turn they phosphorylate other cellular enzymes as well as adaptor or linker proteins lacking catalytic activities.

Recently much attention has been focused on a critical role of the adaptor proteins in the immunoreceptor signaling by the identification of novel hematopoietic linker proteins, including SLP-76 (4) and BASH/SLP-65/BLNK (5–7). SLP-76 and BASH/SLP-65/BLNK are adaptor family members whose expression is restricted to hematopoietic lineages; SLP-76 is expressed in T cells, macrophages, NK cells and mast cells, while BASH/SLP-65/BLNK is expressed in B cells. Common structural features of this adaptor family are the presence of N-terminal tyrosine phosphorylation sites, a central proline-rich region and a C-terminal SH2 domain. Upon TCR and BCR activation, SLP-76 and BASH/SLP-65/BLNK are phosphorylated by Zap70 and Syk respectively, and then associate with a set of signaling proteins, including phospholipase C (PLC), Vav and Grb2 (5–10). Recent studies using genetically engineered cell lines and mice have demonstrated that SLP-76 and BASH/SLP-65/BLNK are essential components in intracellular signaling pathways downstream of TCR and BCR respectively. In a SLP-76-deficient Jurkat T cell line, increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) and activation of the Ras pathway following TCR cross-linking were severely impaired (11). Moreover, a profound block in thymocyte development in SLP-76-deficient mice indicated an essential role of SLP-76 for pre-TCR signaling (12,13). On the other hand, a BLNK-deficient DT40 cell line displayed severe defects in tyrosine phosphorylation of PLC, [Ca²⁺]_i increase and c-Jun N-terminal kinase activation following BCR stimulation (14).

Given the close similarities of the signaling pathways transduced from FcRI and BCR/TCR, we speculated that BASH/SLP-76-related adaptor proteins may be involved in FcRI signaling in mast cells. By the homology search in a database and the following cDNA cloning, we have identified the third member of the BASH/SLP-76 family expressed in mast cells, termed MIST (mast cell immunoreceptor signal transducer), which has later been found to be identical to a recently reported cytokine-dependent hemopoietic cell linker, Clnk (15). Here we show that MIST/Clnk functions as a crucial adaptor molecule in the FcRI signaling pathway leading to mast cell degranulation.

	Methods

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Mast cells
Mouse bone marrow-derived mast cells (BMMC) were prepared by culturing bone marrow cells from C57BL/6 mice in RPMI 1640 medium supplemented with 10% FCS and 10 ng/ml of mouse IL-3 (Peprotech, London, UK), as described (16). Human cord blood-derived mast cells (HCMC) were raised as described by Yanagida et al. (17), and cultured in -MEM supplemented with 12.5% FCS and recombinant human stem cell factor and IL-6 (Peprotech) for at least 10 weeks to obtain a >99% pure mast cell population. RBL-2H3 cells, which were obtained from the Riken Cell Bank, and an IL-3-independent variant of PT-18 mouse mast cell line were also used for the study.

cDNA cloning and expression constructs
The mouse MIST cDNA was isolated from a PT18 cDNA library by 5'- and 3'-RACE (Marathon cDNA amplification kit; Clontech, Palo Alto, CA), using the sequence information from the unidentified expressed sequence tag (EST) cDNA clone (GenBank accession no. AA166259) that had been found to show a homology to BASH. The partial human MIST cDNA was also amplified by PCR from mRNA prepared from HCMC using oligonucleotide primers: 5'-GTGATGATGACTATGATGACCCTGAGCTTC-3' and 5'-GGGAAAATTCTTGTAGTGTTCGATGATGTC-3'. The coding region of mouse MIST cDNA was amplified by PCR, and then inserted between the EcoRI and SalI sites of the pCAT7neo expression vector (6). The MIST mutant (MIST-YF) containing phenylalanine for tyrosine substitutions at positions 69, 96, 101, 153, 174 and 188 was generated by sequential PCR-based mutagenesis using a Quickchange site-directed mutagenesis kit (Stratagene, La Jolla, CA), and then subcloned into the pCAT7neo expression vector.

Antibodies
Rabbit anti-MIST antibody was generated by immunization with a fusion protein composed of amino acids 193–435 of mouse MIST and glutathione-S-transferase (GST). Antisera were precleared with Sepharose beads coupled with GST alone and then purified with an affinity column coupled with GST–MIST fusion protein. Specificity of the affinity-purified antibody was confirmed by immunoblot analysis on cell lysates from COS7 cells transfected with mouse MIST cDNA. Other antibodies used were anti-PLC2 (Santa Cruz Biotechnology, Santa Cruz, CA), anti-Vav (Upstate Biotechnology, Lake Placid, NY), anti-Grb2 (Santa Cruz Biotechnology), anti-linker for activation of T cells (LAT) (Upstate Biotechnology), anti-T7 antibody (Novagen, Madison, WI) and PY20 (Transduction Laboratories, Lexington, KY).

Northern blot, RT-PCR and immunohistochemistry
Total RNA (10 µg) was separated in a denaturing agarose gel, as described previously (6). After blotting, hybridization was performed with either mouse MIST, a full-length mouse BASH or mouse SLP-76 cDNA probes (provided from Dr H. Gu). A mouse ß-actin cDNA probe was also used to normalize the amount of RNA loaded in each lane. For RT-PCR, 2 µg total RNA was reverse-transcribed using an oligo(dT) primer and 1/20th of the resultant cDNA was subjected to PCR amplification. Oligonucleotide primers used were 5'-TATGACCAGCCAGGGCAATAAAAGGACAAC-3' and 5'-CTTACTCATGAAGTGCCTGGCTGGAGTAC-3' for mouse MIST, and primers described above for human MIST cDNA respectively. Normalization was done using primers specific for G3PDH mRNA. The PCR was carried out as follows: 30 cycles of 94°C, 30 s and 68°C, 2 min. The tyramid-based signal amplification method (NEN Life Science, Boston, MA) was used for immunohistochemical analysis. Frozen sections of skin were first incubated with the affinity-purified anti-MIST antibody, rinsed and incubated with horseradish peroxidase (HRP)-labeled anti-rabbit IgG antibody, then with biotinylated tyramid. The reactions were developed by streptavidin–HRP and 3-amino-9-ethylcarbazole. The serial sections were also stained with toluidine blue (pH 4.0) for detecting mast cells.

Immunoprecipitation and immunoblotting
RBL-2H3 cells were transfected by electroporation with either pCAT7neo-MIST-WT, MIST-YF or empty vector and selected in medium containing Geneticin (Gibco, Grand Island, NY) at 1 mg/ml. Stable expression of the transfected MIST was verified by Western blotting with anti-T7 antibody. These clones were incubated with 10 µg/ml of anti-DNP mouse IgE (Sigma, St Louis, MO) for 1 h on ice and then stimulated with 100 ng/ml of DNP-HSA at 37°C for the indicated period of time. Cells were lysed with 1% NP-40 lysis buffer containing protease and phosphatase inhibitors, and immunoprecipitated with indicated antibodies. The immunoprecipitates and aliquots of total cell lysates were resolved on SDS–PAGE and transferred to PVDF membranes. The membranes were immunoblotted with antibodies described above and the secondary antibodies conjugated with HRP, and then developed with the ECL system (Amersham, Arlington Heights, IL). COS7 cells were co-transfected with 1 µg of pCAT7neo-MIST with the indicated combination of 1 µg of pME-Lyn, pME-Syk, or pEF-BOS-Btk plasmids (18,19) using a TransIT-LT1 transfection reagent (Pan Vera, Madison, WI). After incubation for 48 h, cell lysates were prepared and analyzed for tyrosine phosphorylation described above.

Degranulation assay
RBL-2H3 cells (2x10⁵ cells in 0.4 ml, 24-well plates) stably transfected with a mock vector or with a vector encoding MIST-WT or MIST-YF were sensitized overnight with 1 µg/ml of DNP-specific IgE. Cells were subsequently washed twice with PBS and stimulated with various amounts of DNP-HSA at 37°C for 30 min. Degranulation was monitored by the release of ß-hexosaminidase, as previously described (16). Percent degranulation was calculated as activity in the culture medium/activity in the culture medium + activity in the cell lysate.

Measurement of [Ca²⁺]_i concentration
RBL-2H3 cells (5x10⁶) expressing MIST-WT and MIST-YF were loaded with 5 µM Fura-2/AM (Molecular Probes, Eugene, OR) in the presence of 10 µg/ml of DNP-specific IgE at 37°C for 30 min, washed twice with Tyrode buffer containing 0.1% BSA and then stimulated with 100 ng/ml of DNP-HSA or ionomycin (1 µM) at 37°C. [Ca²⁺]_i was monitored at a 510 nm emission wavelength excited by 340 and 360 nm using a fluorescence spectrophotometer (F-4500; Hitachi, Tokyo, Japan) (16).

Luciferase assay
RBL-2H3 cell clones were transiently transfected with 10 µg of a luciferase reporter plasmid driven by seven tandem copies of the NF-AT response element from the mouse IL-2 gene promoter (a gift from Dr K. Arai) in serum-free RPMI at a density of 6x10⁶ cells/400 µl per cuvette with a gene pulser (BioRad, Hercules, CA) set at 250 V and 975 µF. After electroporation, the cells were transferred to complete RPMI and incubated at 37°C for 24 h. Cells (2x10⁶) were then sensitized overnight with 1 µg/ml of DNP-specific IgE and then either left unstimulated or stimulated with DNP-HSA (50 ng/ml) or phorbol myristate acetate (50 ng/ml) plus ionomycin (1 µM) for 6 h. Luciferase activity was monitored, as described previously (6).

	Results

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Identification of a BASH/SLP-76-related molecule expressed in mast cells
By screening the EST database, we identified a cDNA clone from a 13.5-day-old mouse embryo cDNA library (GenBank accession no. AA166259) that exhibited significant amino acid homology to the SH2 domain of chicken BASH. By Northern blot analysis, mRNA corresponding to this clone was undetectable in adult bone marrow, spleen, lymph nodes, thymus, lung and brain (data not shown). Further analysis, however, revealed that a 1.8 kb mRNA corresponding to this clone was expressed in a mastocytoma line, P815, but not in any other hematopoietic or non-hematopoietic lineage cell lines representative of B cells, T cells and macrophages (Fig. 1A). Because of its expression pattern and function (described below), we have named this molecule MIST. After isolation of a full-length mouse MIST cDNA and a partial human MIST cDNA, we further examined the expression of MIST mRNA by RT-PCR in IL-3-induced BMMC and HCMC. MIST transcripts were readily detected in these two normal mast cell cultures (Fig. 1B). MIST were also weakly expressed in other mouse mast cell line PT18 and rat mast cell line RBL-2H3, but not in human basophil precursor (KU812), eosinophil precursor (EOL-1), T cell (Jurkat) or B cell (Ramos) lines.

View larger version (59K): [in this window] [in a new window]   Fig. 1. Expression patterns of mouse and human MIST. (A) Northern blot analysis of mouse MIST, BASH and SLP-76 mRNA expression in hematopoietic and non-hematopoietic cell lines: 18-81 (pre-B cell), WEHI279 (B cell), L1210 (B lymphoid precursor), J558L and P3U1 (plasma cells), EL-4 and BW5147 (T cells), P388D1 and WEHI3 (macrophage), P815 (mast cell), B8/3 (erythroid cell), and B16, Y1, NIH3T3 and ES-E14 (non-hematopoietic cells). (B) RT-PCR analysis of MIST mRNA expression in mouse and rat mast cells: BMMC, PT18 and RBL-2H3; and human hematopoietic lineage cells: HCMC (mast cell), Jurkat (T cell), Ramos (B cell), KU812 (basophil precursor) and EOL-1 (eosinophil precursor). The single-stranded cDNAs prepared from total RNA were amplified by using primers specific for mouse and human MIST. The G3PDH mRNA was also amplified as a standard. (C and D) Immunohistochemical analysis of MIST protein expression in mast cells infiltrating the atopic skin lesions from NC/Nga mice. Infiltrating mast cells whose cytoplasmic granules were metachromatically stained by toluidine blue (C) were also stained with anti-MIST antibody (D).

 
To examine expression of MIST protein, we raised a rabbit serum against mouse MIST. The affinity-purified antibody recognized a 60 kDa protein in BMMC as well as in COS7 cells transfected with the mouse MIST cDNA (data not shown). Using the anti-MIST antibody, we stained serial sections of skin from NC/Nga mice, which spontaneously develop atopic dermatitis-like lesions (20), to clarify the cell populations expressing MIST in situ. Remarkably, the mast cells infiltrating the skin of NC/Nga mice, which were detected by toluidine blue staining (Fig. 1C), were the only cells that expressed MIST protein in the lesions (Fig. 1D). Furthermore, mast cells in normal skin also express MIST protein, as determined by immunohistochemistry (data not shown).

MIST is a novel member of the BASH/SLP-76 adaptor protein family
The mouse MIST cDNA is predicted to encode a 435 amino acid protein, with a calculated mol. wt of 49 kDa (Fig. 2). From the N-terminus to the central region of the molecule, MIST protein contains eight tyrosine residues at amino acid positions 69, 96, 101, 153, 174, 188, 249 and 286, all of which display consensus motifs that could mediate the interaction with other proteins containing an SH2 domain (21,22). The C-terminal part of the protein contains an SH2 domain that is most homologous to that of mouse SLP-76 and BASH/SLP-65/BLNK (41 and 38% identity respectively). The central region of the protein is rich in prolines and contains one potential Grb2 SH3 domain-binding sequence (PXXPXR) (23). Comparison of a partial human MIST sequence with mouse MIST revealed that five tyrosine residues are conserved between species, two of which are also found in SLP-76 and BASH/SLP-65/BLNK. Human MIST has one additional PXXPXR SH3-binding motif between amino acid positions 246 and 251 (Fig. 2). During the analysis of RT-PCR products of MIST mRNA, potential alternatively spliced variants of mouse and human MIST were also identified. The shorter form of mouse MIST lacks 24 amino acids (amino acid positions from 5 to 28) located proximal to N-terminus of the protein, while 37 amino acids (amino acid positions from 147 to 183) in the proline-rich region are missing in the shorter form of human MIST. MIST does not contain a stretch of acidic or basic amino acid residues in its N-terminus, but apart from that the overall structure of MIST is very similar to that of BASH/SLP-65/BLNK and SLP-76. We thus concluded that MIST is a third member of the BASH/SLP-76 adaptor family.

View larger version (58K): [in this window] [in a new window]   Fig. 2. The predicted amino acid sequences of mouse and human MIST. The sequences of mouse and human MIST were aligned with mouse BASH/SLP-65 (GenBank accession nos AB015290/Y17159: these differ by 4 amino acids from mouse BLNK, AF068182) and mouse SLP-76 (U20159). Identical amino acids are indicated by black shading. The numbers in the left column indicate the position of amino acid residues. Tyrosine residues in the potential SH2-binding motifs are shown by closed circles (conserved between mouse and human MIST) and open circles (conserved among MIST, BASH/SLP-65 and SLP-76) above the sequence. The PXXPXR SH3-binding motifs are overlined above the sequence. The SH2 domain is underlined. The sequence of mouse and human MIST have been deposited at DDBJ/GenBank/EMBL database under the accession nos AB021220 and AB032369.

 
During the submission of this manuscript, a sequence identical to the mouse MIST was reported as a cytokine-dependent hemopoietic cell linker (Clnk) (15). Mouse Clnk mRNA was reported to be detected not only in IL-3-induced BMMC but also in IL-2-activated T and NK cells or IL-2/3-dependent cell lines. Clnk mRNA was also detected in a few cytokine-independent cell lines, including a mastocytoma cell line P815, as we have shown above. A possibility of constitutive expression of MIST/Clnk is discussed below (see Discussion).

MIST/Clnk functions as an adaptor protein in FcRI signaling
We next examined whether MIST/Clnk is a substrate of FcRI-associated PTK. For this purpose, we used a rat mast cell line, RBL-2H3, which has been extensively studied for FcRI-signaling. Expression vectors encoding a wild-type (MIST-WT) or a mutant (MIST-YF; see below) form of mouse MIST tagged with the T7 epitope at the N-terminus were transfected into RBL-2H3 cells. Clones stably expressing high levels of MIST proteins were established and the cloned cells were sensitized with anti-DNP-IgE, followed by challenge with DNP-HSA. MIST was tyrosine phosphorylated even before stimulation, and the level of phosphorylation rapidly increased as early as 10 s and reached a maximum at 30 s after the FcRI cross-linking (Fig. 3A). In addition, several tyrosine phosphorylated proteins were co-precipitated with MIST, including a 55 kDa unidentified phosphoprotein (Fig. 3A). By using a panel of antibodies against known PTK substrates, we identified the association of MIST with PLC2 and Vav (Fig 3 B). Grb2 was also found to be co-precipitated with MIST. By contrast, MIST-YF, which has phenylalanines substituted for tyrosines at positions 69, 96, 101, 153, 174 and 188, failed to be tyrosine phosphorylated after FcRI cross-linking. MIST-YF was also unable to associate with PLC2 and Vav, but still retained the ability to associate with Grb2. The reciprocal experiment using anti-Vav, anti-PLC2 and anti-Grb2 antibodies for immunoprecipitation confirmed these results (data not shown). These data suggest that MIST/Clnk functions as a crucial adaptor protein downstream of FcRI, in a manner similar to the function of BASH/SLP-65/BLNK and SLP-76 in BCR and TCR signalings.

View larger version (45K): [in this window] [in a new window]   Fig. 3. MIST/Clnk functions as an adaptor protein downstream of the FcRI signaling. (A) Tyrosine phosphorylation of MIST in a mast cell line. RBL-2H3 cells stably expressing T7-tagged MIST-WT were stimulated for the indicated time periods with DNP-specific IgE and DNP-HSA. MIST was then immunoprecipitated by anti-T7 antibody and immunoblotted with anti-phosphotyrosine (pY, upper panel). Total cell lysates were immunoblotted with anti-T7 (lower panel) antibodies. (B) The interaction of MIST with other signaling molecules upon FcRI cross-linking. RBL-2H3 cells stably expressing T7-tagged MIST-WT (WT) and MIST-YF (YF) were left unstimulated (–) or stimulated (+) with DNP-specific IgE and DNP-HSA for 1 min. Anti-T7 immunoprecipitates were immunoblotted with the indicated antibodies. (C) MIST is tyrosine-phosphorylated by Lyn. COS7 cells were co-transfected with expression plasmids encoding T7-MIST-WT, Lyn, Syk and Btk as indicated (+). The tyrosine phosphorylation of immunoprecipitated T7-MIST was determined by immunoblotting with anti-pY antibody (upper most). Expression of T7-MIST, Lyn, Syk and Btk was determined by immunoblotting total cell lysates with the indicated antibodies.

 
To identify PTK responsible for the phosphorylation of MIST/Clnk, COS7 cells were co-transfected with expression vectors encoding MIST and Lyn, Syk and Btk. Co-expression of Lyn with or without the other kinases induced significant tyrosine phosphorylation of MIST (Fig. 3C). In contrast, co-expression of either Syk or Btk, alone or together, did not induce tyrosine phosphorylation of MIST/Clnk. This suggests that Lyn is primarily responsible for the observed phosphorylation, although the possibility of Syk- and Btk-mediated phosphorylation of MIST/Clnk in mast cells cannot be excluded. This Lyn-mediated phosphorylation of MIST appears to differ from the observation that BASH/SLP-65/BLNK and SLP-76 are substrates for Syk/Zap-70, but not for Lyn kinase, in B cells and T cells, respectively (5–7).

Overexpression of a mutant form of MIST/Clnk abolished FcRI-mediated mast cell degranulation
We next examined whether MIST/Clnk is functionally involved in FcRI-mediated degranulation using the RBL-2H3 cell stable transfectants. Although overexpression of wild-type MIST had no effect on FcRI-induced degranulation, overexpression of MIST-YF significantly suppressed this response (Fig. 4A). Overexpression of either MIST-WT and MIST-YF did not affect degranulation response induced by ionomycin, which by-pass the receptor-proximal signal activation (data not shown). Since elevation in [Ca²⁺]_i is believed to be required for the mast cell degranulation response, we examined [Ca²⁺]_i increase, NF-AT transcriptional activation and phosphorylation of signaling molecules involved in the [Ca²⁺]_i increase. Upon FcRI cross-linking, [Ca²⁺]_i increase in RBL-2H3 clones expressing MIST-YF was diminished to almost half the level of that in clones expressing MIST-WT (Fig. 4B). Furthermore, the FcRI-mediated NF-AT activation, which is believed to be dependent on both Ras and calcium pathways (24), was substantially reduced in a MIST-YF-expressing clone, as compared with a mock-transfected clone (Fig. 4C). However, there was no significant difference in tyrosine phosphorylation of PLC2, Vav (Fig. 4D) and PLC1 (data not shown). In the clones expressing MIST-YF, we observed reduced tyrosine phosphorylation of LAT, which is a critical linker molecule in TCR signaling (25–27). LAT was found to associate with MIST-WT, but not with MIST-YF (Fig. 4D). Although the mechanism by which the mutant form of MIST interferes with tyrosine phosphorylation of LAT remains unclear, it is likely that MIST is situated upstream of LAT in the FcRI signaling pathway and regulates the interaction of Syk with its potential substrate, LAT (26).

View larger version (27K): [in this window] [in a new window]   Fig. 4. Effect of MIST/Clnk on the FcRI-mediated mast cell function. (A) FcRI-induced degranulation response of RBL-2H3 clones stably transfected with MIST-WT (WT), MIST-YF (YF) and empty (Mock) expression vectors. Cells sensitized with DNP-specific IgE were stimulated with the indicated amount of DNP-HSA for 30 min. ß-Hexosaminidase activity in the culture medium and cell lysates was measured, and percent degranulation was deduced as described in Methods. The graph represents mean + SEM (vertical bars) of three independent experiments. (B) FcRI-induced intracellular calcium mobilization in RBL-2H3 cells expressing MIST-WT and MIST-YF. Cells sensitized with DNP-specific IgE were stimulated with 100 ng/ml of DNP-HSA (indicated by an arrow) and [Ca2+]i was measured as in Methods. (C) FcRI-induced NF-AT transcriptional activity in RBL-2H3 cells expressing MIST-WT and MIST-YF. The indicated cell lines were transiently transfected with a NF-AT-luciferase reporter plasmid. After an overnight sensitization with DNP-specific IgE, induction of NF-AT activity was analyzed in unstimulated cells (white bars) or cells stimulated with DNP-HSA (black bars) for 6 h. Data are graphed as percentage of luciferase activity compared to cells stimulated with phorbol myristate acetate plus ionomycin. The graph represents mean + SEM (vertical bars) of three independent experiments. (D) FcRI-induced tyrosine phosphorylation of PLC2, Vav and LAT in RBL-2H3 cells expressing MIST-WT and MIST-YF. Cells were left unstimulated (–) or stimulated (+) with anti-DNP-specific IgE and DNP-HSA for 1 min. Immunoprecipitates (IP) were immunoblotted (Blot) with the indicated antibodies.

 

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
The data presented here indicated that MIST/Clnk is structurally and functionally similar to BASH and SLP-76 adaptor proteins, and functions as a crucial signaling component for FcRI-mediated mast cell degranulation. Overexpression of a mutant form of MIST (MIST-YF) in RBL-2H3 cells severely inhibited FcRI-mediated mast cell degranulation, [Ca²⁺]_i increase, NF-AT-activation and LAT tyrosine phosphorylation. This mutant MIST presumably acts as a dominant negative form by competing with the endogenous MIST/Clnk for interaction with other signaling molecules via proline-rich or SH2 domains. Thus, MIST/Clnk is likely to link the FcRI and the associated PTK to the downstream signaling molecules by physical interactions.

The observed calcium defect in MIST-YF-expressing RBL cell clones is most likely due to reduced activity of PLC, although the tyrosine phosphorylation of PLC appears unaffected. Several lines of evidence support the notion that net tyrosine phosphorylation of PLC may not correctly reflect the functional activation of PLC (28,29). PLC is primarily phosphorylated by Syk, but additional phosphorylation by Btk is believed to be required for full activation of PLC (30), although no definitive evidence has been provided in the context of FcRI signaling in mast cells. For activation of Btk, membrane targeting of Btk through interaction of its PH domain and phosphatidylinositol-3,4,5-triphosphate generated by phosphatidylinositol-3-kinase appears to be necessary (31). Thus, one possible mechanism by which a mutant form of MIST suppresses FcRI-mediated [Ca²⁺]_i increase could be an interference with the activation or function of either phosphatidylinositol-3-kinase or Btk, in which an endogenous MIST is involved. In this regard, tyrosine-phosphorylated BASH/SLP-65/BLNK, a B cell analogue of MIST/Clnk, was recently reported to bind to the SH2 domain of Btk and to facilitate Btk to target PLC as a substrate (32), suggesting a possible interplay between MIST/Clnk, Btk and PLC.

Alternatively, the reduced tyrosine phosphorylation of LAT caused by overexpression of a dominant negative MIST may imply that MIST/Clnk is involved in LAT-mediated assembly of signaling molecules including PLC at a detergent-resistant membrane raft, which is a specialized membrane domain serving as the center for receptor-mediated activation (33). The apparent discrepancy between impaired calcium elevation and preserved PLC2 tyrosine phosphorylation in MIST-YF-expressing RBL-2H3 cells might be partly ascribed to the potential lack of PLC2-LAT assembly, because the raft is enriched with PLC substrate, phosphatidylinositol-4,5-biphosphate (34). Furthermore, it has been noted that mast cells from LAT-deficient mice display an impaired FcRI-mediated degranulation (35). Therefore, it is possible to think that MIST/Clnk may bring LAT in the vicinity of Syk to allow it to be phosphorylated and to potentiate it to be a scaffold protein which brings together the signaling proteins essential for degranulation.

SLP-76, a structural relative of MIST/Clnk, has been reported to be expressed in mast cells and be tyrosine phosphorylated upon the FcRI engagement in RBL-2H3 cells (36). Because both MIST/Clnk and SLP-76 can associate with a similar set of signaling proteins, including PLC, Vav and Grb2 (4,9,10), the observed tyrosine phosphorylation of PLC in MIST-YF-expressing clones may be mediated by SLP-76. Similar to the MIST-YF-expressing RBL-2H3 cell clones we described here, FcRI-mediated degranulation and cytokine production of BMMC from SLP-76-deficient mice were almost completely abrogated, whereas phosphorylation of PLC and Vav and the [Ca²⁺]_i response were not drastically reduced (37). Unlike SLP-76, MIST/Clnk is phosphorylated by Lyn and is involved in phosphorylation of LAT. Thus, SLP-76 and MIST are likely to be functionally non-redundant in FcRI signaling of mast cells. A careful dissection of functions of MIST/Clnk and SLP-76 may shed new light on the complexity of FcRI-mediated signaling that triggers diverse sets of mast cell functions.

Cao et al. reported that expression of Clnk was restricted to cytokine-dependent cell lines with a few exceptions of cytokine-independent cell lines such as P815 mast cell line (15). Cao et al. speculated that activated mutation of c-Kit in P815 mastocytoma cells resulted in the induction of Clnk mRNA in this cytokine-independent cell line. However, we have evidence that MIST/Clnk mRNA is up-regulated by IL-3 and IL-4, but not by c-Kit ligand in a IL-3-starved mast cell line, although c-Kit receptor was expressed in the same cell line (data not shown). Therefore, c-Kit activation may not account for the constitutive expression of MIST/Clnk mRNA in all mast cell lines. Furthermore, we observed the mast cell-specific expression of MIST/Clnk in skin from NC/Nga as well as normal mice. Together, it is possible that mast cells express MIST/Clnk constitutively.

We could not detect the significant MIST/Clnk expression in cells except for mast cells in allergic skin from NC/Nga mice. This might be due to the fact that local concentration of cytokines at the allergic sites is not high enough to induce MIST/Clnk expression in T or NK cells, compared to the in vitro experimental conditions described by Cao et al. (15). Thus, the cytokine-induced expression of MIST/Clnk in vivo remains to be tested.

If the expression of MIST/Clnk is up-regulated by cytokines in vivo, it would be feasible that, at sites of allergic reaction, MIST/Clnk mediates the cross-talk between the signals from FcRI and cytokine receptors: cytokines released by T cells and also by mast cells themselves will up-regulate expression of MIST/Clnk in mast cells, which may in turn render FcRI hypersensitive to the antigen–IgE complex. As such, MIST/Clnk may be an ideal target for potential therapeutic intervention in allergy and mast cell malignancies.

	Acknowledgments

 
We thank Drs H. Gu, T. Watanabe, S. Tsukada, H. Nishizumi, K. Arai, K. Kawamoto, Y. Furumoto and M. Yanagida for materials, and Drs P. D. Burrows and M. D. Cooper for critical reading of the manuscript. Supported by grants for PRESTO from JST and from the Ministry of Education, Culture and Science of Japan.

	Abbreviations

 

BCR B cell receptor

BMMC bone marrow-derived mast cells

[Ca2+]i intracellular Ca2+ concentration

EST expressed sequence tag

FcRI high-affinity IgE receptor

GST glutathione-S-transferase

HCMC human cord blood-derived mast cells

HRP horseradish peroxidase

LAT linker for activation of T cells

PLC phospholipase C

PTK protein tyrosine kinase

	Notes

 
Transmitting editor: K. Okumura

Received 8 January 2000, accepted 20 January 2000.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. Kinet, J. P. 1999. The high-affinity IgE receptor (Fc epsilon RI): from physiology to pathology. Annu. Rev. Immunol. 17:931.[Web of Science][Medline]
2. Clements, J. L., Boerth, N. J., Lee, J. R. and Koretzky, G. A. 1999. Integration of T cell receptor-dependent signaling pathways by adapter proteins. Annu. Rev. Immunol. 17:89.[Web of Science][Medline]
3. Kurosaki, T. 1999. Genetic analysis of B cell antigen receptor signaling. Annu. Rev. Immunol. 17:555.[Web of Science][Medline]
4. Jackman, J. K., Motto, D. G., Sun, Q., Tanemoto, M., Turck, C. W., Peltz, G. A., Koretzky, G. A. and Findell, P. R. 1995. Molecular cloning of SLP-76, a 76-kDa tyrosine phosphoprotein associated with Grb2 in T cells. J. Biol. Chem. 270:7029.[Abstract/Free Full Text]
5. Fu, C., Turck, C. W., Kurosaki, T. and Chan, A. C. 1998. BLNK: a central linker protein in B cell activation. Immunity 9:93.[Web of Science][Medline]
6. Goitsuka, R., Fujimura, Y., Mamada, H., Umeda, A., Morimura, T., Uetsuka, K., Doi, K., Tsuji, S. and Kitamura, D. 1998. BASH, a novel signaling molecule preferentially expressed in B cells of the bursa of Fabricius. J. Immunol. 161:5804.[Abstract/Free Full Text]
7. Wienands, J., Schweikert, J., Wollscheid, B., Jumaa, H., Nielsen, P. J. and Reth, M. 1998. SLP-65: a new signaling component in B lymphocytes which requires expression of the antigen receptor for phosphorylation. J. Exp. Med. 188:791.[Abstract/Free Full Text]
8. Wardenburg, J. B., Fu, C., Jackman, J. K., Flotow, H., Wilkinson, S. E., Williams, D. H., Johnson, R., Kong, G., Chan, A. C. and Findell, P. R. 1996. Phosphorylation of SLP-76 by the ZAP-70 protein-tyrosine kinase is required for T-cell receptor function. J. Biol. Chem. 271:19641.[Abstract/Free Full Text]
9. Wu, J., Motto, D. G., Koretzky, G. A. and Weiss, A. 1996. Vav and SLP-76 interact and functionally cooperate in IL-2 gene activation. Immunity 4:593.[Web of Science][Medline]
10. Tuosto, L., Michel, F. and Acuto, O. 1996. p95 vav associates with tyrosine-phosphorylated SLP-76 in antigen-stimulated T cells. J. Exp. Med. 184:1161.[Abstract/Free Full Text]
11. Yablonski, D., Kuhne, M. R., Kadlecek, T. and Weiss, A. 1998. Uncoupling of nonreceptor tyrosine kinases from PLC-1 in an SLP-76-deficient T cell. Science 281:413.[Abstract/Free Full Text]
12. Clements, J. L., Yang, B., Ross-Barta, S. E., Eliason, S. L., Hrstka, R. F., Williamson, R. A. and Koretzky, G. A. 1998. Requirement for the leukocyte-specific adaptor protein SLP-76 for normal T cell development. Science 281:416.[Abstract/Free Full Text]
13. Pivniouk, V., Tsitsikov, E., Swinton, P., Rathbun, G., Alt, F. W. and Geha, R. S. 1998. Impaired viability and profound block in thymocyte development in mice lacking the adaptor protein SLP-76. Cell 94:229.[Web of Science][Medline]
14. Ishiai, M., Kurosaki, M., Pappu, R., Okawa, K., Ronko, I., Fu, C., Shibata, M., Iwamatsu, A., Chan, A. C. and Kurosaki, T. 1999. BLNK required for coupling Syk to PLC2 and Rac-1JNK in B cells. Immunity 10:117.[Web of Science][Medline]
15. Cao, M. Y., Davidson, D., Yu, J., Latour, S. and Veillette, A. 1999. Clnk, a novel SLP-76-related adaptor molecule expressed in cytokine-stimulated hemopoietic cells. J. Exp. Med. 190:1527.[Abstract/Free Full Text]
16. Hiraoka, S., Furumoto, Y., Koseki, H., Takagaki, Y., Taniguchi, M., Okumura, K. and Ra, C. 1999. Fc receptor ß subunit is required for full activation of mast cells through Fc receptor engagement. Int. Immunol. 11:199.[Abstract/Free Full Text]
17. Yanagida, M., Fukamachi, H., Ohgami, K., Kuwaki, T., Ishii, H., Uzumaki, H., Amano, K., Tokiwa, T., Mitsui, H. and Saito, H. 1995. Effects of T-helper 2-type cytokines, interleukin-3 (IL-3), IL-4, IL-5, and IL-6 on the survival of cultured human mast cells. Blood 86:3705.[Abstract/Free Full Text]
18. Yamanashi Y., Fukuda T., Nishizumi H., Inazu T., Higashi K., Kitamura D., Ishida T., Yamamura H., Watanabe T. and Yamamoto T. 1997. Role of tyrosine phosphorylation of HS1 in B cell antigen receptor-mediated apoptosis. J. Exp. Med. 185:1387.[Abstract/Free Full Text]
19. Matsushita M., Yamadori T., Kato S., Takemoto Y., Inazawa J., Baba Y., Hashimoto S., Sekine S., Arai S., Kunikata T., Kurimoto M., Kishimoto T. and Tsukada S. 1998. Identification and characterization of a novel SH3-domain binding protein, Sab, which preferentially associates with Bruton's tyrosine kinase (BtK). Biochem. Biophys. Res. Commun. 245:337.[Web of Science][Medline]
20. Matsuda, H., Watanabe, N., Geba, G. P., Sperl, J., Tsudzuki, M., Hiroi, J., Matsumoto, M., Ushio, H., Saito, S., Askenase, P. W. and Ra. C. 1997. Development of atopic dermatitis-like skin lesion with IgE hyperproduction in NC/Nga mice. Int. Immunol. 9:491.
21. Songyang, Z., Shoelson, S. E., Chaudhuri, M., Gish, G., Pawson, T., Haser, W. G., King, F., Roberts, T., Ratnofsky, S., Lechleider, R. J., Neel, B. G., Birge, R. B., Fajardo, J. E., Chou, M. M., Hanafusa, H., Schaffhausen, B. and Cantley, L. C. 1993. SH2 domains recognize specific phosphopeptide sequences. Cell 72:767.[Web of Science][Medline]
22. Songyang, Z., Shoelson, S. E., McGlade, J., Olivier, P., Pawson, T., Bustelo, X. R., Barbacid, M., Sabe, H., Hanafusa, H., Yi, T., Ren. R., Baltimore, D., Ratnofsky, S., Feldman, R. A. and Cantley, L. C. 1994. Specific motifs recognized by the SH2 domains of Csk, 3BP2, fps/fes, GRB2, HCP, SHC, Syk, and Vav. Mol. Cell. Biol. 14:2777.[Abstract/Free Full Text]
23. Simon, J. A. and Schreiber, S. L. 1995. Grb2 SH3 binding to peptides from Sos: evaluation of a general model for SH3–ligand interactions. Chem. Biol. 2, 53.[Web of Science][Medline]
24. Woodrow, M., Clipstone, N. A. and Cantrell, D. 1993. p21 ras and calcineurin synergize to regulate the nuclear factor of activated T cells. J. Exp. Med. 178:1517.[Abstract/Free Full Text]
25. Finco, T. S., Kadlecek, T., Zhang, W., Samelson, L. E. and Weiss, A. 1998. LAT is required for TCR-mediated activation of PLC1 and the Ras pathway. Immunity 9:617.[Web of Science][Medline]
26. Zhang, W., Sloan-Lancaster, J., Kitchen, J., Trible, R. P. and Samelson, L. E. 1998. LAT: the ZAP-70 tyrosine kinase substrate that links T cell receptor to cellular activation. Cell 92:83.[Web of Science][Medline]
27. Zhang, W., Irvin, B. J., Trible, R. P., Abraham, R. T. and Samelson, L. E. 1999. Functional analysis of LAT in TCR-mediated signaling pathways using a LAT-deficient Jurkat cell line. Int. Immunol. 11:943.[Abstract/Free Full Text]
28. Fluckiger, A. C., Li, Z., Kato, R. M., Wahl, M. I., Ochs, H. D., Longnecker, R., Kinet, J. P., Witte, O. N., Scharenberg, A. M. and Rawlings, D. J. 1998. Btk/Tec kinases regulate sustained increases in intracellular Ca²⁺ following B-cell receptor activation. EMBO J. 17:1973.[Web of Science][Medline]
29. Costello, P. S., Walters, A. E., Mee, P. J., Turner, M., Reynolds, L. F., Prisco, A., Sarner, N., Zamoyska, R. and Tybulewicz, V. L. 1999. The Rho-family GTP exchange factor Vav is a critical transducer of T cell receptor signals to the calcium, ERK, and NF-B pathways. Proc. Natl. Acad. Sci. U S A 96:3035.[Abstract/Free Full Text]
30. Takata, M. and Kurosaki, T. 1996. A role for Bruton's tyrosine kinase in B cell antigen receptor-mediated activation of phospholipase C-2. J. Exp. Med. 184:31.[Abstract/Free Full Text]
31. Scharenberg, A. M., EI-Hillal, O., Fruman, D. A., Beitz, L. O., Li, Z., Lin, S, Gout, I., Cantley, L. C., Rawlings, D. J. and Kinet, J.-P. 1998. Phosphatidylinositol-3,4,5-trisphosphate (PtdIns-3,4,5-P3)/Tec kinase-dependent calcium signaling pathway: a target for SHIP-mediated inhibitory signals. EMBO J. 17:1961.[Web of Science][Medline]
32. Hashimoto, S., Iwamatsu, A., Ishiai, M., Okawa, K., Yamadori, T., Matsushita, M., Baba, Y., Kishimoto, T., Kurosaki, T. and Tsukada, S. 1999. Identification of the SH2 domain binding protein of Bruton's tyrosine kinase as BLNK—functional significance of btk–SH2 domain in B-cell antigen receptor-coupled calcium signaling. Blood 94:2357.[Abstract/Free Full Text]
33. Xavier, R. and Seed, B. 1999. Membrane compartmentation and the response to antigen. Curr. Opin. Immunol. 11:265.[Web of Science][Medline]
34. Pike, L. J. and Casey, L. 1996. Localization and turnover of phosphatidylinositol 4,5-bisphosphate in caveolin-enriched membrane domains. J. Biol. Chem. 271:26453.[Abstract/Free Full Text]
35. Zhang, W., Sommers, C. L., Burshtyn, D. N., Stebbins, C. C., DeJarnette, J. B., Trible, R. P., Grinberg, A., Tsay, H. C., Jacobs, H. M., Kessler, C. M., Long, E. O., Love, P. E. and Samelson, L. E. 1999. Essential role of LAT in T cell development. Immunity 10:323.[Web of Science][Medline]
36. Hendricks-Taylor, L. R., Motto, D. G., Zhang, J., Siraganian, R. P. and Koretzky, G. A. 1997. SLP-76 is a substrate of the high affinity IgE receptor-stimulated protein tyrosine kinases in rat basophilic leukemia cells. J. Biol. Chem. 272:1363.[Abstract/Free Full Text]
37. Pivniouk, V. I., Martin, T. R., Lu-Kuo, J. M., Katz, H. R., Oettgen, H. C. and Geha, R. S. 1999. SLP-76 deficiency impairs signaling via the high affinity IgE receptor in mast cells. J. Clin. Invest. 103:1737.[Web of Science][Medline]

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