期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1990
卷号:87
期号:18
页码:7085-7089
DOI:10.1073/pnas.87.18.7085
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:Immunoprecipitation of Thy-1 from Triton X-100 detergent lysates of surface-iodinated and chemically cross-linked T cells precipitated at least five major and discrete bands. Four of these bands were identified as Thy-1, CD45 (a transmembrane tyrosine phosphatase), a major histocompatibility complex-encoded class I molecule, and beta 2-microglobulin. Similar analyses revealed that CD45 was coprecipitated from lysates of cross-linker-treated cells by antibodies to the T-cell antigen receptor (TCR). The same pattern of coprecipitated bands was observed when digitonin was used to lyse untreated cells. Immunoprecipitation of Thy-1 or the TCR from lysates of cross-linked T cells precipitated CD45 tyrosine phosphatase activity. Calculations based upon the amounts of coprecipitated enzymatic activity or TCR zeta chain indicate that a substantial fraction of Thy-1 and TCR complexes can be cross-linked to CD45. These data support a model in which the dependence of Thy-1 signaling on TCR coexpression is due to their common interaction with a tyrosine phosphatase and provide a possible structural basis for the influence of CD45 on TCR-mediated signaling.