A novel type of regulatory protein for the GDP/GTP exchange reaction of rho p21, a ras p21-like small GTP-binding protein, in rabbit intestine.
A novel regulatory protein for rho p21, a ras p21-like GTP-binding protein (G protein), was purified from the cytosol fraction of rabbit intestine. This protein, designated as rho GDP dissociation inhibitor (GDI), regulated the GDP/GTP exchange reaction of rho p21 by inhibiting the dissociation of GDP from and subsequent binding of GTP to it. rho GDI did not affect the GTPase activity of rho p21. rho GDI formed a complex with the GDP-bound form of rho p21 but not the GTP-bound form. rho GDI was inactive for other small G proteins including ras p21, smg p21 and smg p25A. These results indicate that rho GDI is a novel type of regulatory protein for the GDP/GTP exchange reaction of rho p21.
Ohga
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Department of Biochemistry, Kobe University School of Medicine.
D000818:Animals; D002853:Chromatography, Liquid; D019204:GTP-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D020730:Guanine Nucleotide Dissociation Inhibitors; D066298:In Vitro Techniques; D007422:Intestines / Q000737:chemistry*; D011506:Proteins / Q000378:metabolism; D011817:Rabbits; D014461:Ultracentrifugation; D020703:ras GTPase-Activating Proteins; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D020742:rhoA GTP-Binding Protein
D020690:GTPase-Activating Proteins; D020730:Guanine Nucleotide Dissociation Inhibitors; D011506:Proteins; D020703:ras GTPase-Activating Proteins; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D019204:GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein