A Dual E3 mechanism for Rub1 ligation to Cdc53

Scott, D. C., Monda, J. K., Grace, C. R.R., Duda, D. M., Kriwacki, R. W., Kurz, T. and Schulman, B. A. (2010) A Dual E3 mechanism for Rub1 ligation to Cdc53. Molecular Cell, 39(5), pp. 784-796. (doi: 10.1016/j.molcel.2010.08.030) (PMID:20832729) (PMCID:PMC3001161)

Abstract

In ubiquitin-like protein (UBL) cascades, a thioester-linked E2∼UBL complex typically interacts with an E3 enzyme for UBL transfer to the target. Here we demonstrate a variant mechanism, whereby the E2 Ubc12 functions with two E3s, Hrt1 and Dcn1, for ligation of the UBL Rub1 to Cdc53's WHB subdomain. Hrt1 functions like a conventional RING E3, with its N terminus recruiting Cdc53 and C-terminal RING activating Ubc12∼Rub1. Dcn1's “potentiating neddylation” domain (Dcn1P) acts as an additional E3, reducing nonspecific Hrt1-mediated Ubc12∼Rub1 discharge and directing Ubc12's active site to Cdc53. Crystal structures of Dcn1P-Cdc53WHB and Ubc12 allow modeling of a catalytic complex, supported by mutational data. We propose that Dcn1's interactions with both Cdc53 and Ubc12 would restrict the otherwise flexible Hrt1 RING-bound Ubc12∼Rub1 to a catalytically competent orientation. Our data reveal mechanisms by which two E3s function synergistically to promote UBL transfer from one E2 to a target.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kurz, Dr Thimo
• Authors: Scott, D. C., Monda, J. K., Grace, C. R.R., Duda, D. M., Kriwacki, R. W., Kurz, T., and Schulman, B. A.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Molecular Cell
• Publisher: Elsevier (Cell Press)
• ISSN: 1097-2765
• ISSN (Online): 1097-4164
• Published Online: 09 September 2010