TY - JOUR
T1 - An 81 kd protein complexed with middle T antigen and pp60c-src
T2 - A possible phosphatidylinositol kinase
AU - Courtneidge, Sara A.
AU - Heber, Angelika
PY - 1987/9/25
Y1 - 1987/9/25
N2 - It has previously been shown that a proportion of middle T antigen molecules exist in a stable complex with pp60c-src. Here we show that there appears to be a third component to the complex, a protein of molecular mass 81 kd (p81). p81 was phosphorylated exclusively on tyrosine residues in kinase assays performed using immunoprecipitates from polyoma virus-transformed cells and antibodies to both middle T and pp60c-src, and was also detected when immunoprecipitates were made from lysates of 32P-labeled cells. p81 was bound to middle T and pp60c-src in cell lines containing transforming mutants of middle T, but not (in phosphorylated form) to all nontransforming mutants. A parallel investigation of phosphatidylinositol kinase activity in immune complexes containing these middle T mutants revealed a complete coincidence between the presence of p81 and phosphatidylinositol kinase activity. We therefore suggest that p81 is a phosphatidylinositol kinase.
AB - It has previously been shown that a proportion of middle T antigen molecules exist in a stable complex with pp60c-src. Here we show that there appears to be a third component to the complex, a protein of molecular mass 81 kd (p81). p81 was phosphorylated exclusively on tyrosine residues in kinase assays performed using immunoprecipitates from polyoma virus-transformed cells and antibodies to both middle T and pp60c-src, and was also detected when immunoprecipitates were made from lysates of 32P-labeled cells. p81 was bound to middle T and pp60c-src in cell lines containing transforming mutants of middle T, but not (in phosphorylated form) to all nontransforming mutants. A parallel investigation of phosphatidylinositol kinase activity in immune complexes containing these middle T mutants revealed a complete coincidence between the presence of p81 and phosphatidylinositol kinase activity. We therefore suggest that p81 is a phosphatidylinositol kinase.
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U2 - 10.1016/0092-8674(87)90169-3
DO - 10.1016/0092-8674(87)90169-3
M3 - Article
C2 - 2441879
AN - SCOPUS:0023665027
SN - 0092-8674
VL - 50
SP - 1031
EP - 1037
JO - Cell
JF - Cell
IS - 7
ER -