Tian F, Li D, Xia H, Liu X, Jia W, Sun C, Sun K, Jin B
Department of Immunology, The Fourth Military Medical University, Xi'an, People's Republic of China.
DNA Seq. 1999;10(3):155-61. doi: 10.3109/10425179909033941.
Human platelet and T cell activation antigen 1 (PTA1) is a 67kDa type I transmembrane glycoprotein mainly expressed on the surface of activated T cells and platelets, and is involved in the development of human cytotoxic T cell (CTL) as well as platelet activation and aggregation. We have cloned and sequenced gibbon PTA1 (gPTA1) and monkey PTA1 (mPTA1) cDNAs by RT-PCR from gibbon leukemic cell line MLA 144 and PHA-induced Rhesus monkey PBMC respectively. The mature proteins of gPTA1, mPTA1 and human PTA1 (hPTA1) share 93-95% amino acid similarity with the highest similarity in domain 1 of extracellular region. All the important features of PTA1 molecule are conserved among these Primates: (1) the ORF encoding 336 amino acid residues including signal sequence (18aa), extracellular region (232aa), transmembrane sequence (25aa) and cytoplasmic region (61aa); (2) two conserved pairs of Cys (Cys19 to Cys90 and Cys134 to Cys204) forming disulfide bonds stabilizing the two immunoglobulin superfamily V-like domains; (3) eight putative N-linked glycosylation sites (except gPTA1 with nine sites) and three O-linked glycosylation sites in extracellular region; and (4) predicated protein kinase C phosphorylation sites (Thr275 and Ser311), casein kinase II sites (Ser295 and The299) and the potential tyrosine phosphorylation site (Tyr304). These data indicate that PTA1 molecule is highly conserved among the Primates and may play important roles in immune response.
人血小板和T细胞活化抗原1（PTA1）是一种67kDa的I型跨膜糖蛋白，主要表达于活化T细胞和血小板表面，参与人细胞毒性T细胞（CTL）的发育以及血小板的活化和聚集。我们分别通过RT-PCR从长臂猿白血病细胞系MLA 144和PHA诱导的恒河猴外周血单个核细胞中克隆并测序了长臂猿PTA1（gPTA1）和猴PTA1（mPTA1）的cDNA。gPTA1、mPTA1和人PTA1（hPTA1）的成熟蛋白在氨基酸水平上具有93%-95%的相似性，在细胞外区域的结构域1中相似性最高。PTA1分子的所有重要特征在这些灵长类动物中都是保守的：（1）开放阅读框编码336个氨基酸残基，包括信号序列（18个氨基酸）、细胞外区域（232个氨基酸）、跨膜序列（25个氨基酸）和细胞质区域（61个氨基酸）；（2）两对保守的半胱氨酸（Cys19至Cys90和Cys134至Cys204）形成二硫键，稳定两个免疫球蛋白超家族V样结构域；（3）细胞外区域有八个推定的N-连接糖基化位点（gPTA1有九个位点）和三个O-连接糖基化位点；（4）预测的蛋白激酶C磷酸化位点（Thr275和Ser311）、酪蛋白激酶II位点（Ser295和The299）以及潜在的酪氨酸磷酸化位点（Tyr304）。这些数据表明，PTA1分子在灵长类动物中高度保守，可能在免疫反应中发挥重要作用。
