The Cullin-RING E3 ubiquitin ligase CRL4-DCAF1 complex dimerizes via a short helical region in DCAF1.

The cullin4A-RING E3 ubiquitin ligase (CRL4) is a multisubunit protein complex, comprising cullin4A (CUL4), RING H2 finger protein (RBX1), and DNA damage-binding protein 1 (DDB1). Proteins that recruit specific targets to CRL4 for ubiquitination (ubiquitylation) bind the DDB1 adaptor protein via WD40 domains. Such CRL4 substrate recognition modules are DDB1- ...
and CUL4-associated factors (DCAFs). Here we show that, for DCAF1, oligomerization of the protein and the CRL4 complex occurs via a short helical region (residues 845-873) N-terminal to DACF1's own WD40 domain. This sequence was previously designated as a LIS1 homology (LisH) motif. The oligomerization helix contains a stretch of four Leu residues, which appear to be essential for α-helical structure and oligomerization. In vitro reconstituted CRL4-DCAF1 complexes (CRL4(DCAF1)) form symmetric dimers as visualized by electron microscopy (EM), and dimeric CRL4(DCAF1) is a better E3 ligase for in vitro ubiquitination of the UNG2 substrate compared to a monomeric complex.
Mesh Terms:
Amino Acid Motifs, Amino Acid Sequence, Animals, Carrier Proteins, Cell Line, Humans, Insects, Mice, Molecular Sequence Data, Peptides, Protein Multimerization, Protein Structure, Quaternary, Protein Structure, Tertiary, Rats, Repetitive Sequences, Amino Acid, Solutions, Ubiquitin-Protein Ligases
Biochemistry
Date: Mar. 01, 2011
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