title: Scythe regulates apoptosis through modulating ubiquitin-mediated proteolysis of the Xenopus elongation factor XEF1AO.
abstract: Scythe was originally identified as a novel Reaper-binding anti-apoptotic protein, although the mechanisms of its functions remain largely obscure. Our previous analysis revealed that Scythe can bind to a proteasomal subunit via N-terminal domains and that the domains are required for appropriate development of Xenopus embryos. In the present study, we show evidence that the N-terminus of Scythe interacts with XEF1AO, a maternal form of Xenopus laevis EF1A that was suggested to be a potential inducer of apoptosis in vertebrates, and that the binding enhances the poly-ubiquitin modification and subsequent degradation of XEF1AO. Scythe is required for degradation of XEF1AO, since immunodepletion of Scythe from embryonic extracts stabilized XEF1AO significantly. Furthermore, we show that apoptosis induced by accumulation of XEF1AO can be suppressed by co-expression of the full-length form of Scythe. These observations indicate that the proteolytic regulation of XEF1AO, mediated through Scythe, is essential to prevent inappropriate accumulation of XEF1AO and resulting apoptotic events during the course of Xenopus development.
authors.affiliation: Department of Biochemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Minami
authors.forename: Masumi
authors.initials: M
authors.lastname: Shimada
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Yokosawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kawahara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D020648:Peptide Elongation Factor 1 / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000378:metabolism*
chemical_list: C116358:BAG6 protein, Xenopus; D002352:Carrier Proteins; D018832:Molecular Chaperones; D020648:Peptide Elongation Factor 1; D029867:Xenopus Proteins; C521933:eef1a1o protein, Xenopus