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Specific association of phosphatidylinositol 3‐kinase with the protooncogene product Cbl in Fcγ receptor signaling
Author(s) -
Matsuo Tsuyoshi,
Hazeki Kaoru,
Hazeki Osamu,
Katada Toshiaki,
Ui Michio
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00122-6
Subject(s) - phosphatidylinositol , chemistry , kinase , signal transduction , association (psychology) , receptor , microbiology and biotechnology , biochemistry , biology , psychology , psychotherapist
A tyrosine‐phosphorylated protein with a molecular mass of 115 kDa was reported to be tightly associated with the p85 regulatory subunit of phosphatidylinositol (PI) 3‐kinase, when the enzyme was essentially activated upon ligand engagement of Fcγ receptors (FcγR) leading to engulfment of IgG‐coated erythrocytes by phagocytes [Ninomiya et al. (1994) J. Biol. Chem. 269, 22732‐22737]. Here, the 115‐kDa protein is identified as the product of human c‐ cbl protooncogene. Cross‐linking of FcγRII on the surface of THP‐1 cells triggered (a) prominent tyrosine phosphorylation of Cbl, (b) activation of PI 3‐kinase that was immunoprecipitated with the anti‐Cbl or the anti‐phosphotyrosine antibody, and (c) specific association of Cbl with p85, Thus, Cbl functions in phagocytes as a result of its association with PI 3‐kinase in response to FcγR ligation.