PMID: 22632832 , Related PDB id: 4EOZ

Authors:

Errington WJ, Khan MQ, Bueler SA, Rubinstein JL, Chakrabartty A, Prive GG

Title:

Adaptor protein self-assembly drives the control of a cullin-RING ubiquitin ligase.

Journal:

Structure. 2012 Jul 3;20(7):1141-53. Epub 2012 May 24.

Abstract:

The E3 ligases recruit substrate proteins for targeted ubiquitylation. Recent insights into the mechanisms of ubiquitylation demonstrate that E3 ligases can possess active regulatory properties beyond those of a simple assembly scaffold. Here, we describe the dimeric structure of the E3 ligase adaptor protein SPOP (speckle-type POZ protein) in complex with the N-terminal domain of Cul3 at 2.4 A resolution. We find that SPOP forms large oligomers that can form heteromeric species with the closely related paralog SPOPL. In combination, SPOP and SPOPL (SPOP-like) form a molecular rheostat that can fine-tune E3 ubiquitin ligase activity by affecting the oligomeric state of the E3 complex. We propose that adaptor protein self-assembly provides a graded level of regulation of the SPOP/Cul3 E3 ligase toward its multiple protein substrates.