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Template:STRUCTURE 1he8

RAS G12V-PI 3-KINASE GAMMA COMPLEX

Overview

Ras activation of phosphoinositide 3-kinase (PI3K) is important for survival of transformed cells. We find that PI3Kgamma is strongly and directly activated by H-Ras G12V in vivo or by GTPgammaS-loaded H-Ras in vitro. We have determined a crystal structure of a PI3Kgamma/Ras.GMPPNP complex. A critical loop in the Ras binding domain positions Ras so that it uses its switch I and switch II regions to bind PI3Kgamma. Mutagenesis shows that interactions with both regions are essential for binding PI3Kgamma. Ras also forms a direct contact with the PI3Kgamma catalytic domain. These unique Ras/PI3Kgamma interactions are likely to be shared by PI3Kalpha. The complex with Ras shows a change in the PI3K conformation that may represent an allosteric component of Ras activation.

About this Structure

1HE8 is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.

Reference

Crystal structure and functional analysis of Ras binding to its effector phosphoinositide 3-kinase gamma., Pacold ME, Suire S, Perisic O, Lara-Gonzalez S, Davis CT, Walker EH, Hawkins PT, Stephens L, Eccleston JF, Williams RL, Cell. 2000 Dec 8;103(6):931-43. PMID:11136978 Page seeded by OCA on Fri May 2 18:45:27 2008