Kung C, Okumura M, Seavitt J R, Noll M E, White L S, Pingel J T, Thomas M L
Howard Hughes Medical Institute, Department of Pathology and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Eur J Immunol. 1999 Dec;29(12):3951-5. doi: 10.1002/(SICI)1521-4141(199912)29:12<3951::AID-IMMU3951>3.0.CO;2-9.
CD45 is a transmembrane protein tyrosine phosphatase required for signaling through the T-and B-cell antigen receptors. In lymphocytes, CD45 interacts with CD45-associated protein (CD45AP), a 32 000 Mr phosphoprotein, through their respective transmembrane domains. To determine whether CD45AP affects the ability of CD45 to regulate antigen receptor signaling, CD45AP-deficient mice were generated. Thymocyte development was grossly normal. Moreover, the cellularity of the thymus and spleens were normal. CD45 expression on thymocytes and splenocytes, ascertained by flow cytometry, was comparable between CD45AP-deficient mice and littermate controls. In contrast to a previous report (Matsuda et al., J. Exp. Med. 1998 187: 1863 - 1870). CD45AP-deficient and normal thymocytes and splenocytes proliferated similarly in response to various mitogens or antigen receptor cross-linking. Furthermore, thymocyte CD45-associated p56(lck) kinase activity was similar between CD45AP-deficient and normal cells. We conclude that CD45AP is not essential for the regulation of Src-family kinase activity by CD45.
CD45是一种跨膜蛋白酪氨酸磷酸酶，是T细胞和B细胞抗原受体信号传导所必需的。在淋巴细胞中，CD45通过其各自的跨膜结构域与CD45相关蛋白（CD45AP，一种32000道尔顿的磷蛋白）相互作用。为了确定CD45AP是否影响CD45调节抗原受体信号传导的能力，制备了CD45AP缺陷小鼠。胸腺细胞发育基本正常。此外，胸腺和脾脏的细胞数量正常。通过流式细胞术确定，CD45AP缺陷小鼠和同窝对照小鼠胸腺细胞和脾细胞上的CD45表达相当。与之前的一份报告（松田等人，《实验医学杂志》1998年，187:1863 - 1870）相反，CD45AP缺陷和正常的胸腺细胞和脾细胞对各种有丝分裂原或抗原受体交联的增殖反应相似。此外，CD45AP缺陷细胞和正常细胞之间胸腺细胞CD45相关的p56(lck)激酶活性相似。我们得出结论，CD45AP对于CD45调节Src家族激酶活性并非必不可少。
