Association between GTPase activators for Rho and Ras families

• Published in: Nature (London) Vol. 359; no. 6391; pp. 153 - 154
• Main Authors: Settleman, Jeffrey, Albright, Charles F, Foster, Lauren C, Weinberg, Robert A
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 10.09.1992; Nature Publishing Group
• Subjects: activators; Animals; Biochemistry; Biological and medical sciences; Cell physiology; DNA-Binding Proteins; enzymatic activity; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Genes, ras - physiology; GTP Phosphohydrolases - physiology; GTPase-activating protein; GTPase-Activating Proteins; Guanine Nucleotide Exchange Factors; guanosinetriphosphatase; Insecta - genetics; Medical research; Molecular and cellular biology; Nuclear Proteins - isolation & purification; Nuclear Proteins - physiology; p190 protein; Phosphoproteins - isolation & purification; Phosphoproteins - physiology; Polymerase Chain Reaction; Proteins; Proteins - physiology; ras; ras GTPase-Activating Proteins; Ras protein; rats; Rats - genetics; Repressor Proteins; Rho Factor - physiology; Rho protein; Signal transduction; Transcription, Genetic - physiology; Transfection; Signal transduction; Gene rho; Enzyme; Mitosis; dGTPase; Activation; Cell differentiation; Growth factor; G protein
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/359153a0

The ras-related low-molecular-mass GTPases participate in signal transduction involving a variety of cellular functions, including cell-cycle progression, cellular differentiation, cytoskeletal organization, protein transport and secretion. The cycling of these proteins between GTP-bound and GDP-bound states is partially controlled by GTPase activating proteins (GAPs) which stimulate the intrinsic GTP-hydrolysing activity of specific GTPases. The ras GTPase-activating protein (Ras-GAP) forms a complex with a second protein, p190 (M(r) 190,000), in growth-factor stimulated and tyrosine-kinase transformed cells. At its carboxy-terminal end, p190 contains a region that is conserved in the breakpoint cluster region, n-chimaerin, and Rho-GAP. Each of these three proteins exhibits GAP activity for at least one member of the rho family of small GTPases. We have tested recombinant p190 protein for GAP activity on GTPases of the ras, rho and rab families, and show here that p190 can function as a GAP specifically for members of the rho family. Consequently, the formation of a complex between Ras-GAP and p190 in growth-factor stimulated cells may allow the coupling of signalling pathways that involve ras and rho GTPases.