PMID: 18996392 , Related PDB id: 2K4D

Authors:

Huang A, de Jong RN, Wienk H, Winkler GS, Timmers HT, Boelens R

Title:

E2-c-Cbl recognition is necessary but not sufficient for ubiquitination activity.

Journal:

J Mol Biol. 2009 Jan 16;385(2):507-19. Epub 2008 Nov 1.

Abstract:

The E2 ubiquitin-conjugating enzymes UbcH7 and UbcH5B both show specific binding to the RING (really interesting new gene) domain of the E3 ubiquitin-protein ligase c-Cbl, but UbcH7 hardly supports ubiquitination of c-Cbl and substrate in a reconstituted system. Here, we found that neither structural changes nor subtle differences in the E2-E3 interaction surface are possible explanations for the functional specificity of UbcH5B and UbcH7 in their interaction with c-Cbl. The quick transfer of ubiquitin from the UbcH5B-Ub thioester to c-Cbl or other ubiquitin acceptors suggests that UbcH5B might functionally be a relatively pliable E2 enzyme. In contrast, the UbcH7-Ub thioester is too stable to transfer ubiquitin under our assay conditions, indicating that UbcH7 might be a more specific E2 enzyme. Our results imply that the interaction specificity between c-Cbl and E2 is required but not sufficient for transfer of ubiquitin to potential targets.