A ubiquitin-binding motif required for intramolecular monoubiquitylation, the CUE domain.

Autor: Shih, Susan C., Prag, Gali, Francis, Smitha A., Sutanto, Myra A., Hurley, James H., Hicke, Linda
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Zdroj: EMBO Journal; 3/15/2003, Vol. 22 Issue 6, p1273-1281, 9p
Abstrakt: Monoubiquitylation is a regulatory signal, like phosphorylation, that can alter the activity, location or structure of a protein. Monoubiquitin signals are likely to be recognized by ubiquitin-binding proteins that transmit the regulatory information conferred by monoubiquitylation. To identify monoubiquitin-binding proteins, we used a mutant ubiquitin that tacks the primary site of polyubiquitin chain formation as bait in a two-hybrid screen. The C-terminus of Vps9, a protein required in the yeast endocytic pathway, interacted specifically with monoubiquitin. The region required for monoubiquitin binding mapped to the Vps9 CUE domain, a sequence previously identified by database searches as similar to parts of the yeast Cuel and mammalian Tollip proteins. We demonstrate that CUE domains bind directly to monoubiquitin and we have defined crucial interaction surfaces on both binding partners. The Vps9 CUE domain is required to promote monoubiquitylation of Vps9 by the Rsp5 hect domain ubiquitin ligase. Thus, we conclude that the CUE motif is an evotutionarily conserved monoubiquitin-binding domain that mediates intramolecular monoubiquitylation. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index