Mapping of the p56lck-mediated phosphorylation of GAP and analysis of its influence on p21ras-GTPase activity in vitro.
Biochim Biophys Acta
; 1222(3): 441-6, 1994 Jul 21.
Article
em En
| MEDLINE
| ID: mdl-8038213
ABSTRACT
The protein tyrosine kinase p56lck and other members of the src family can transduce signals from activated cell-surface receptors. As we showed earlier the GTPase-activating protein (GAP), a regulator of p21ras, is a substrate of p56lck. Here, tryptic peptides of p56lck-phosphorylated GAP were generated and analyzed by two-dimensional thin layer chromatography and mass spectroscopy. Results revealed that p56lck phosphorylates GAP specifically on Tyr-460 in vitro and in vivo. The effect of tyrosine phosphorylation of GAP on its GTPase-activating activity versus p21ras was then tested using a p21ras-dependent GTPase assay system. Our results demonstrate that p56lck-mediated tyrosine phosphorylation of GAP is not sufficient to change directly its effect on the intrinsic GTPase activity of p21ras.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas
/
Proteínas Proto-Oncogênicas p21(ras)
/
Proteínas Proto-Oncogênicas
/
GTP Fosfo-Hidrolases
Limite:
Animals
Idioma:
En
Ano de publicação:
1994
Tipo de documento:
Article