Anti-allergic therapy targeting to a mast cell-specific signaling protein

MIST是一种肥大细胞特异性信号蛋白，在结构上与SLP-76和BLNK/BASH/SLP-65造血细胞特异性衔接蛋白相关。本研究利用BLNK缺陷的DT 40鸡B细胞系统，构建了MIST在免疫受体信号转导中的功能分析系统，并为筛选MIST抑制剂开发抗过敏药物奠定了基础。在该重建系统中，MIST可以部分恢复BLNK缺陷细胞中的B细胞抗原受体（BCR）信号传导，这需要两个N-末端酪氨酸残基的磷酸化。LAT与MIST的共表达完全恢复了BCR信号传导，并且免除了MIST中的两个酪氨酸对BCR信号传导的需要。然而，MIST中的一些其他酪氨酸以及SH 2结构域和两个富含脯氨酸的区域仍然需要与LAT合作完全重建BCR信号传导。MIST的C-末端富含脯氨酸的区域被标记用于LAT辅助的完全修复 ...更多信息 MAP激酶激活，虽然它是负责与LAT的相互作用，并在富含糖脂的微域的本地化。另一方面，N-末端富含脯氨酸的区域是PLC g的SH 3结构域的结合位点，对于BCR信号传导是必需的。我们还证明了肥大细胞系中表达的两种主要的与MIST相关的磷蛋白是SIST-130和SKAP-55，它们是已知的与Src家族蛋白酪氨酸激酶（PTK）的SH 2结构域的衔接子，Mist通过其SH 2结构域与SIST-130直接相关，并且SIST-130与SKAP-55的协作是将MIST募集到林恩所必需的。在Fyn-SH 2结构域中，MIST优先被募集到Fyn而不是林恩，这是由SIST-130和SKAP 55与Fyn-SH 2结构域的结合亲和力高于与Lyn-SH 2结构域的结合亲和力调节的。总之，本研究中获得的关于MIST在免疫受体信号传导中的功能的这些信息为使用这种MIST重建的BLNK缺陷型DT 40系统开发抗过敏药物奠定了基础。

MIST is a mast cell-specific signaling protein structurally related to SLP-76 and BLNK/BASH/SLP-65 hematopoietic cell-specific adaptor proteins. By using the BLNK-deficient DT40 chicken B cell system, we constructed the system for analysing the function of MIST in immunoreceptor signaling and also for screening the MIST inhibitors to develop anti-allergic drugs. In this reconstitution system, MIST can partially restore the B cell antigen receptor (BCR) signaling in the BLNK-deficient cells, which requires phosphorylation of the two N-terminal tyrosine residues. Co-expression of LAT with MIST fully restored the BCR signaling, and dispenses with the requirement of the two tyrosines in MIST for BCR signaling. However, some other tyrosine( s ), as well as the SH2 domain and the two proline-rich regions in MIST are still required for full reconstitution of the BCR signaling, in cooperation with LAT. The C-terminal proline-rich region of MIST is dispensable for the LAT-aided full restoration … More of MAP kinase activation, although it is responsible for the interaction with LAT and for the localization in glycolipidenriched microdomains. On the other hand, the N-terminal proline-rich region, which is a binding site of the SH3 domain of PLCg, is essential for BCR signaling. We also demonstrated that two major MIST-associated phosphoproteins expressed in mast cell lines are SLAP-130 and SKAP55, adaptors known to with the SH2 domain of Src-family protein tyrosine kinases (PTKs), Mist directly associated with SLAP-130 via its SH2 domain, and collaboration of SLAP-130 with SKAP-55 was required for the recruitment of MIST to Lyn. Farthermore, MIST was preferentially recruited to Fyn rather than Lyn, which is regulated by higher affinity binding of SLAP-130 and SKAP55 with the Fyn-SH2 domain than the Lyn-SH2 domain. Taken together, these informations on the function of MIST in immunoreceptor signaling obtained in the present study have established the basis on the future development of antiallergic drugs using this MIST-reconstituted BLNK-deficient DT40 system Less