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Characterization of the C‐terminal domain of ras‐GTPase‐activating protein (ras‐GAP) as substrate for epidermal growth factor receptor and p60c‐src kinase
Author(s) -
Borowski Peter,
Kornetzky Lutz,
Heiland Max,
Roloff Sandra,
Weber Wolfgang,
Laufs Rainer
Publication year - 1996
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549600201701
Subject(s) - autophosphorylation , sh3 domain , phosphorylation , gtpase , proto oncogene tyrosine protein kinase src , gtpase activating protein , epidermal growth factor , biology , microbiology and biotechnology , sh2 domain , biochemistry , tyrosine phosphorylation , protein kinase a , signal transduction , receptor , g protein
Abstract We describe in vitro tyrosine phosphorylation of the C‐terminal 334 amino acids of ras‐GTPase‐activating protein (ras‐GAP)1 that contains the activity domain for ras interaction. To date, there have been no other phosphorylation sites determined than the reported in N‐terminal domain of ras‐GAP Tyr‐460, which is considered to be the major phosphorylation site of ras‐GAP. In our assays some differences of the kinetic parameters were observed when the reaction was catalyzed by EGF‐R compared to p60c‐src. Enzyme specific regulation of activity is associated with autophosphorylation which leads to reduced (in case of EGF‐R) or increased (in case of p60c‐src) phosphorylation of the C‐terminal 334 amino acids of ras‐GAP (GAP334). Because of the characteristics of these investigated reactions the phosphorylation of GAP334 seems to be ‐ independent from the presence of SH2 or SH3 domains ‐ triggered off by complex mechanisms different from those regulating the phosphorylation at Tyr‐460.