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EMBO J. 2002 Feb 1;21(3):355-64.

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

Author information

1
Laboratory for Physiological Chemistry, University Medical Center, 3508 AB Utrecht, The Netherlands.

Abstract

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
PMCID:
PMC125831
DOI:
10.1093/emboj/21.3.355
[Indexed for MEDLINE]
Free PMC Article

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