Takeda A, Maizel A L, Kitamura K, Ohta T, Kimura S
Department of Pathology, Roger Williams Medical Center, Brown University, Providence, Rhode Island 02908.
J Biol Chem. 1994 Jan 28;269(4):2357-60.
CD45, a leukocyte-specific transmembrane protein tyrosine phosphatase, mediates signal transduction pathways critical for immune responses. However, the mechanism of CD45-mediated signal transduction and the identity of CD45-associated proteins have remained unclear. A CD45-associated 30-kDA phosphorylated protein (CD45-AP) was purified by virtue of its specific association with CD45, and its mouse cDNA was cloned by using the internal amino acid sequence information. In vitro translated CD45-AP bound specifically to CD45. CD45-AP appears to be leukocyte-specific and shares no significant homology with presently known sequences. The predicted sequence contains no consensus tyrosine phosphorylation sites or conserved sequences of GTP-binding proteins. CD45-AP may act as an adapter molecule for CD45-mediated signal transduction.
CD45是一种白细胞特异性跨膜蛋白酪氨酸磷酸酶，介导对免疫反应至关重要的信号转导途径。然而，CD45介导的信号转导机制以及与CD45相关蛋白的身份仍不清楚。一种与CD45相关的30 kDa磷酸化蛋白（CD45-AP）因其与CD45的特异性结合而被纯化，并利用内部氨基酸序列信息克隆了其小鼠cDNA。体外翻译的CD45-AP特异性结合CD45。CD45-AP似乎是白细胞特异性的，与目前已知的序列没有明显的同源性。预测序列中没有一致的酪氨酸磷酸化位点或GTP结合蛋白的保守序列。CD45-AP可能作为CD45介导的信号转导的衔接分子。
