Format

Send to

Choose Destination
J Biol Chem. 2010 Mar 19;285(12):8595-604. doi: 10.1074/jbc.M109.089003. Epub 2010 Jan 8.

The E2 ubiquitin-conjugating enzymes direct polyubiquitination to preferred lysines.

Author information

1
Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 76100, Israel.

Abstract

The ubiquitin-proteasome pathway plays a crucial role in many cellular processes by degrading substrates tagged by polyubiquitin chains, linked mostly through lysine 48 of ubiquitin. Although polymerization of ubiquitin via its six other lysine residues exists in vivo as part of various physiological pathways, the molecular mechanisms that determine the type of polyubiquitin chains remained largely unknown. We undertook a systematic, in vitro, approach to evaluate the role of E2 enzymes in determining the topology of polyubiquitin. Because this study was performed in the absence of an E3 enzyme, our data indicate that the E2 enzymes are capable of directing the ubiquitination process to distinct subsets of ubiquitin lysines, depending on the specific E2 utilized. Moreover, our findings are in complete agreement with prior analyses of lysine preference assigned to certain E2s in the context of E3 (in vitro and in vivo). Finally, our findings support the rising notion that the functional unit of E2 is a dimer. To our knowledge, this is the first systematic indication for the involvement of E2 enzymes in specifying polyubiquitin chain assembly.

PMID:
20061386
PMCID:
PMC2838281
DOI:
10.1074/jbc.M109.089003
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center