title: A longevity protein, Lag2, interacts with SCF complex and regulates SCF function.
abstract: SCF-type E3-ubiquitin ligases control numerous cellular processes through the ubiquitin-proteasome pathway. However, the regulation of SCF function remains largely uncharacterized. Here, we report a novel SCF complex-interacting protein, Lag2, in Saccharomyces cerevisiae. Lag2 interacts with the SCF complex under physiological conditions. Lag2 negatively controls the ubiquitylation activities of SCF E3 ligase by interrupting the association of Cdc34 to SCF complex. Overexpression of Lag2 increases unrubylated Cdc53, whereas deletion of lag2, together with the deletions of dcn1 and jab1, results in the accumulation of Rub1-modified Cdc53. In vitro rubylation assays show that Lag2 inhibits the conjugation of Rub1 to Cdc53 in competition with Dcn1, which suggest that Lag2 down-regulates the rubylation of Cdc53 rather than promoting derubylation. Furthermore, Dcn1 hinders the association of Lag2 to Cdc53 in vivo. Finally, the deletion of lag2 combined with the deletion of either dcn1 or rub1 suppresses the growth of yeast cells. These observations thus indicate that Lag2 has a significant function in regulating the SCF complex by controlling its ubiquitin ligase activities and its rubylation cycle.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Aichi, Japan.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Satoru
authors.initials: S
authors.lastname: Mimura
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kishi
authors.forename: Takumi
authors.initials: T
authors.lastname: Kamura
mesh_terms: D049109:Cell Proliferation; D044842:Cullin Proteins / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D010641:Phenotype; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination; D014452:Ubiquitins / Q000235:genetics
chemical_list: C100988:Cdc53 protein, S cerevisiae; D044842:Cullin Proteins; C502135:Dcn1 protein, S cerevisiae; C101054:LAG2 protein, S cerevisiae; C111706:RUB1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases