Bruyns E, Hendricks-Taylor L R, Meuer S, Koretzky G A, Schraven B
Department of Applied Immunology, German Cancer Research Center, Heidelberg, Federal Republic of Germany.
J Biol Chem. 1995 Dec 29;270(52):31372-6. doi: 10.1074/jbc.270.52.31372.
Human lymphocyte phosphatase-associated phospho-protein (LPAP) is a phosphoprotein of unknown function that noncovalently associates with CD45 in lymphocytes. In CD45-deficient human T cells, LPAP protein is synthesized at normal levels but is more rapidly degraded than in wild-type cells. Expression of CD45 cDNA rescues LPAP protein expression. This strongly suggests that LPAP is protected from degradation through its interaction with CD45. We have mapped the sites of interaction between LPAP and CD45 employing chimeric CD45 molecules and LPAP deletion mutants. Our data demonstrate that the interaction between LPAP and CD45 is mediated via the transmembrane regions of both molecules. In addition, the intracytoplasmic amino acids adjacent to the transmembrane region of LPAP may influence its binding to CD45.
人淋巴细胞磷酸酶相关磷蛋白（LPAP）是一种功能未知的磷蛋白，它在淋巴细胞中与CD45非共价结合。在缺乏CD45的人T细胞中，LPAP蛋白以正常水平合成，但比野生型细胞中的降解速度更快。CD45 cDNA的表达可挽救LPAP蛋白的表达。这强烈表明LPAP通过与CD45的相互作用而免受降解。我们利用嵌合CD45分子和LPAP缺失突变体绘制了LPAP与CD45之间的相互作用位点。我们的数据表明，LPAP与CD45之间的相互作用是通过两个分子的跨膜区域介导的。此外，LPAP跨膜区域相邻的胞质内氨基酸可能会影响其与CD45的结合。
