Download MendeleyStructural analysis of autoinhibition in the ras activator son of sevenless.
Sondermann, H., Soisson, S.M., Boykevisch, S., Yang, S.S., Bar-Sagi, D., Kuriyan, J.(2004) Cell 119: 393-405
- PubMed: 15507210
- DOI: https://doi.org/10.1016/j.cell.2004.10.005
- Primary Citation of Related Structures:
1XD2, 1XD4, 1XDV - PubMed Abstract:
The classical model for the activation of the nucleotide exchange factor Son of sevenless (SOS) involves its recruitment to the membrane, where it engages Ras. The recent discovery that Ras*GTP is an allosteric activator of SOS indicated that the regulation of SOS is more complex than originally envisaged. We now present crystallographic and biochemical analyses of a construct of SOS that contains the Dbl homology-pleckstrin homology (DH-PH) and catalytic domains and show that the DH-PH unit blocks the allosteric binding site for Ras and suppresses the activity of SOS. SOS is dependent on Ras binding to the allosteric site for both a lower level of activity, which is a result of Ras*GDP binding, and maximal activity, which requires Ras*GTP. The action of the DH-PH unit gates a reciprocal interaction between Ras and SOS, in which Ras converts SOS from low to high activity forms as Ras*GDP is converted to Ras*GTP by SOS.
Organizational Affiliation:
Howard Hughes Medical Institute, Department of Molecular and Cell Biology and Department of Chemistry, University of California, Berkeley, CA 94720, USA.
