Interaction of Nck-associated protein 1 with activated GTP-binding protein Rac.

摘要: Bacterially expressed glutathione S-transferase fusion proteins containing Rac1 were used to identify binding of this Rho family GTPase present in a bovine brain extract. Five 85, 110, 125, 140 and 170 kDa detected, all which associated exclusively with guanosine 5'-[gamma-thio]triphosphate-bound Rac1, not GDP-bound Rac1. The 85 110 identified as the regulatory catalytic subunits respectively phosphatidylinositol 3-kinase. Several lines evidence suggested that 125 protein is identical Nck-associated 1 (Nap1). mobilities Nap1 on SDS/PAGE indistinguishable, was depleted from extract by preincubation Src homology 3 domain Nck binds. Furthermore, antibodies reacted protein. co-immunoprecipitated constitutively active form Rac Chinese hamster ovary cells. observation complex formation between activated PAK, but Nap1, could be reproduced vitro recombinant indicates interaction indirect. Rac-binding potential candidate for link connects Rac. multimolecular comprising Rac, probably might mediate some biological effects transmitted multipotent GTPase.