1XD4

Crystal structure of the DH-PH-cat module of Son of Sevenless (SOS)

Summary for 1XD4

• Entry DOI: 10.2210/pdb1xd4/pdb
• Related: 1BKD 1DBH 1NVV 1XD2
• Descriptor: Son of sevenless protein homolog 1 (1 entity in total)
• Functional Keywords: nucleotide exchange factor, ras, cdc25, ras exchanger motif (rem), dbl homology(dh), pleckstrin homology (ph), signaling protein
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 198791.91

Authors

Sondermann, H.,Soisson, S.M.,Boykevisch, S.,Yang, S.S.,Bar-Sagi, D.,Kuriyan, J. (deposition date: 2004-09-03, release date: 2004-11-02, Last modification date: 2023-08-23)

Primary citation

Sondermann, H.,Soisson, S.M.,Boykevisch, S.,Yang, S.S.,Bar-Sagi, D.,Kuriyan, J.
Structural analysis of autoinhibition in the ras activator son of sevenless.
Cell(Cambridge,Mass.), 119:393-405, 2004

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.

PubMed: 15507210
DOI: 10.1016/j.cell.2004.10.005

Experimental method

X-RAY DIFFRACTION (3.64 Å)