Mutational and kinetic analyses of the GTPase-activating protein (GAP)-p21 interaction: the C-terminal domain of GAP is not sufficient for full activity.
AUTOR(ES)
Gideon, P
RESUMO
The GTPase-activating protein (GAP) stimulates the GTPase reaction of p21 by 5 orders of magnitude such that the kcat of the reaction is increased to 19 s-1. Mutations of residues in loop L1 (Gly-12 and Gly-13), in loop L2 (Thr-35 and Asp-38), and in loop L4 (Gln-61 and Glu-63) influence the reaction in different ways, but all of these mutant p21 proteins still form complexes with GAP. The C-terminal domain of the human GAP gene product, GAP334, which comprises residues 714 to 1047, is 20 times less active than full-length GAP on a molar basis and has a fourfold lower affinity. This finding indicates that the N terminus of GAP containing the SH2 domains modifies the interaction between the catalytic domain and p21.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=364376Documentos Relacionados
- A C-terminal domain of GAP is sufficient to stimulate ras p21 GTPase activity.
- Effector domain mutations dissociate p21ras effector function and GTPase-activating protein interaction.
- Suppression of src transformation by overexpression of full-length GTPase-activating protein (GAP) or of the GAP C terminus.
- The C-terminal domain of NifL is sufficient to inhibit NifA activity.
- p21ras activation via hemopoietin receptors and c-kit requires tyrosine kinase activity but not tyrosine phosphorylation of p21ras GTPase-activating protein.