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1: EMBO J. 2002 Feb 1;21(3):355-64.Click here to read Click here to read Links

Identification of a ubiquitin-protein ligase subunit within the CCR4-NOT transcription repressor complex.

Albert TK, Hanzawa H, Legtenberg YI, de Ruwe MJ, van den Heuvel FA, Collart MA, Boelens R, Timmers HT.

Laboratory for Physiological Chemistry, University Medical Center, 3508 AB Utrecht, The Netherlands.

The RING finger protein CNOT4 is a component of the CCR4-NOT complex. This complex is implicated in repression of RNA polymerase II transcription. Here we demonstrate that CNOT4 functions as a ubiquitin-protein ligase (E3). We show that the unique C4C4 RING domain of CNOT4 interacts with a subset of ubiquitin-conjugating enzymes (E2s). Using NMR spectroscopy, we detail the interaction of CNOT4 with UbcH5B and characterize RING residues that are critical for this interaction. CNOT4 acts as a potent E3 ligase in vitro. Mutations that destabilize the E2-E3 interface abolish this activity. Based on these results, we present a model of how E3 ligase function within the CCR4-NOT complex relates to transcriptional regulation.

PMID: 11823428 [PubMed - indexed for MEDLINE]

PMCID: PMC125831