Identification of the binding surface on Cdc42Hs for p21-activated kinase

摘要: The Ras superfamily of GTP-binding proteins is involved in a number cellular signaling events including, but not limited to, tumorigenesis, intracellular trafficking, and cytoskeletal organization. Rho subfamily, which Cdc42Hs member, cell morphogenesis through GTPase cascade regulates changes. has been shown to stimulate DNA synthesis as well initiate protein kinase that begins with the activation p21-activated serine/threonine kinases (PAKs). We have determined previously solution structure [Feltham et al. (1997) Biochemistry 36, 8755-8766] using NMR spectroscopy. A minimal-binding domain 46 amino acids PAK was identified (PBD46), binds KD approximately 20 nM inhibits GTP hydrolysis. binding interface mapped by producing fully deuterated sample 15N-Cdc42Hs bound PBD46. 1H,15N-NOESY-HSQC spectrum demonstrated surface on consists second beta-strand (beta2) portion loop between first alpha-helix (alpha1) beta2 (switch I). complex PBD46 15N-Cdc42Hs.GMPPCP exhibited extensive chemical shift changes 1H,15N-HSQC spectrum. Thus, likely produces structural are interface, consistent its effects These results suggest kinase-binding similar more than, c-Raf-binding antagonist, Rap1 [Nassar (1995) Nature 375, 554-560)].