Interaction Between Syntaxin 8 and HECTd3, a HECT Domain Ligase
Ubiquitination of proteins and their degradation within the proteasome has emerged as the major proteolytic mechanism used by mammalian cells to regulate cytosolic and nuclear protein levels. Substrate ubiquitylation is mediated by ubiquitin (Ub) ligases, also called E3 Ub ligases. HECT-E3 Ub ligases are characterized by the presence of a C-terminal HECT domain that contains the active site for Ub transfer onto substrates. Among the many E3 Ub ligases, the family homologous to E6-Ap C-terminus (HECT) E3 Ub ligases, which includes the yeast protein Rsp5p and the mammalian homolog NEDD4, AIP4/Itch, and Smurf, has been shown to ubiquitylate membrane proteins and, in some instances, to induce their degradation. In this report, we have identified Syntaxin 8 as a binding protein to a novel HECT domain protein, HECT domain containing 3 (HECTd3), by yeast two-hybrid screen. Besides HECT domain, HECTd3 contains an anaphase-promoting complex, subunit 10 (APC10) domain. Our co-immunoprecipitation experiments show that Syntaxin 8 directly interacts with HECTd3 and that the overexpression of HECTd3 promotes the ubiquitination of Syntaxin 8. Immunofluorescence results show that Syntaxin 8 and HECTd3 have similar subcellular localization.
KeywordsSyntaxin 8 Ubiquitination HECT E3 ubiquitin ligases HECTd3
- Bogdanovic A, Bennett N, Kieffer S, Louwagie M, Morio T, Garin J, Satre M, Bruckert F (2002) Syntaxin 7, syntaxin 8, Vti1 and VAMP7 (vesicle-associated membrane protein 7) form an active SNARE complex for early macropinocytic compartment fusion in Dictyostelium discoideum. Biochem J 368(Pt 1):29–39PubMedCrossRefGoogle Scholar
- Yu J, Lan J, Zhu Y, Li X, Lai X, Xue Y, Jin C, Huang H (2008) The E3 ubiquitin ligase HECTD3 regulates ubiquitination and degradation of Tara. Biochem Biophys Res Commun 367`(4):805–812Google Scholar