Sauer K, Liou J, Singh S B, Yablonski D, Weiss A, Perlmutter R M
Department of Immunology and Rheumatology and Department of Molecular Systems, Merck Research Laboratories, Rahway, New Jersey 07065, USA.
J Biol Chem. 2001 Nov 30;276(48):45207-16. doi: 10.1074/jbc.M106811200. Epub 2001 Aug 3.
B cell linker protein (BLNK) is a SLP-76-related adaptor protein essential for signal transduction from the BCR. To identify components of BLNK-associated signaling pathways, we performed a phosphorylation-dependent yeast two-hybrid analysis using BLNK probes. Here we report that the serine/threonine kinase hematopoietic progenitor kinase 1 (HPK1), which is activated upon antigen-receptor stimulation and which has been implicated in the regulation of MAP kinase pathways, interacts physically and functionally with BLNK in B cells and with SLP-76 in T cells. This interaction requires Tyr(379) of HPK1 and the Src homology 2 (SH2) domain of BLNK/SLP-76. Via homology modeling, we defined a consensus binding site within ligands for SLP family SH2 domains. We further demonstrate that the SH2 domain of SLP-76 participates in the regulation of AP-1 and NFAT activation in response to T cell receptor (TCR) stimulation and that HPK1 inhibits AP-1 activation in a manner partially dependent on its interaction with SLP-76. Our data are consistent with a model in which full activation of HPK1 requires its own phosphorylation on tyrosine and subsequent interaction with adaptors of the SLP family, providing a mechanistic basis for the integration of this kinase into antigen receptor signaling cascades.
B细胞连接蛋白（BLNK）是一种与SLP-76相关的衔接蛋白，对来自BCR的信号转导至关重要。为了鉴定与BLNK相关的信号通路成分，我们使用BLNK探针进行了磷酸化依赖性酵母双杂交分析。在此我们报告，丝氨酸/苏氨酸激酶造血祖细胞激酶1（HPK1）在抗原受体刺激后被激活，并且与MAP激酶通路的调节有关，它在B细胞中与BLNK以及在T细胞中与SLP-76在物理和功能上相互作用。这种相互作用需要HPK1的Tyr(379)以及BLNK/SLP-76的Src同源2（SH2）结构域。通过同源建模，我们定义了SLP家族SH2结构域配体内的一个共有结合位点。我们进一步证明，SLP-76的SH2结构域参与了T细胞受体（TCR）刺激后AP-1和NFAT激活的调节，并且HPK1以部分依赖于其与SLP-76相互作用的方式抑制AP-1激活。我们的数据与这样一个模型一致，即HPK1的完全激活需要其自身酪氨酸磷酸化以及随后与SLP家族衔接蛋白的相互作用，为该激酶整合到抗原受体信号级联反应中提供了一个机制基础。
