CD45在T细胞激活过程中的作用

CD45是免疫系统主要的跨膜酷氨酸磷酸酶,已经形成的共识认为,CD45的信号转导过程中单一的起着正调节作用,促进了生命信号向细胞内的传播,模型阐述了CD45在信号过程中的双重作用,为近期的试验提供了理论解释。

THE FUNCTION OF CD45 IN T CELL ACTIVATION

CD45 is a predominant transmembrane tyrosine phosphatase in lymphocytes.A number of laboratories suggest that the surface expression of this molecule is required for normal signal events to occur in T cell. Although the model for the relationship between CD45 and Src-family PTKs, which says that CD45 dephosphorylates the C-terminal negative regulatory tyrosine, tyr505, is well known, it does not explain the experimental observation in which CD45 inhibits the activation of Src-family kinases. In fact, both of the regulatory tyrosine residues in lck, tyr394, the important positive regulatory tyrosine in signal transduction, and tyr505 are CD45 substrates in vitro. Here, using a nonlinear model, a quantitative model in which CD45 is both a positive and negative regulator of Src-family membrane kinases is proposed and the importance of SH2 domains is confirmed.