Tyrosine phosphorylation of a c-Src-like protein is increased in membranes of CD4- CD8- T lymphocytes from lpr/lpr mice.
Tyrosine phosphorylation of a c-Src-like protein is increased in membranes of CD4- CD8- T lymphocytes from lpr/lpr mice.
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lpr/lpr 小鼠的 CD4-CD8-T 淋巴细胞膜中 c-Src 样蛋白的酪氨酸磷酸化增加。
DOI：
10.1128/mcb.9.11.4914-4922.1989
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发表时间：
1989
影响因子：
5.3
通讯作者：
Earp,HS
中科院分区：
文献类型：
--
作者：
Katagiri,T;Ting,JP;Dy,R;Prokop,C;Cohen,P;Earp,HS
Mice homozygous for the autosomal recessivelprgene have a disorder that results in autoimmunity and massive accumulation of T lymphocytes lacking CD4 and CD8 surface markers. These abnormal T cells exhibit constitutive tyrosine phosphorylation of a component of the CD3-T-cell receptor complex. We compared membrane tyrosine phosphorylation inlpr/lprCD4-CD8-T cells and control T cells.lprmembranes exhibited a 7.3-fold increase (n= 16) in tyrosine phosphorylation of a 60-kilodalton protein. The increase was correlated with the Lpr but not the CD4-CD8-phenotype in that p60 phosphorylation was not increased in membranes from normal CD4-CD8-thymocytes. To identify the p60 inlprcells, we examined the activity of several T-cell tyrosine-specific protein kinases. p56lckphosphorylation was only slightly increased inlprmembranes (2.2-fold;n =16). Phorbol ester treatment of intact T cells before membrane isolation caused p56lckto migrate as pp60lck; however, pp60lckcould be clearly distinguished from the pp60 inlprcells by two-dimensional gel electrophoresis. The pp60 fromlprcells exhibited several isoforms at pH ~6.3 to 6.5. Although on two-dimensional gels pp60c-srchad a pI (6.4 to 6.8) within a similar region, p60c-srcmRNA, protein, and kinase activities were not increased inlprcells. In addition, staphylococcal V8 proteolytic cleavage of thelprpp60 isolated on two-dimensional gels yielded two major fragments, a pattern distinct from that of pp60c-src. However, by using an antiserum against the C-terminal sequence of c-Src and other related kinases, including p59fyn, the pp60 could be immunoprecipitated in greater amounts fromlprthan from control T cells. When pp59fynwas selectively immunoprecipitated from T-cell membranes with specific antisera, its molecular weight, proteolytic cleavage pattern, and behavior on two-dimensional gels were identical to those of the pp60 fromlprcells. We conclude that p59fynphosphorylation is increased in membranes fromIpr/lprCD4-CD8-T cells and that the increase is correlated with constitutive tyrosine phosphorylation and perhaps with the expansion of this unusual T-cell population.
