新規SCF複合体活性調節因子の発見

Here, I am very honored to introduce our recent work about the new regulator of SCF complex .

Our group focuses our research interest on the Cullin-RING Ligase (CRL), especially SCF-type E3 ubiquitin ligases. We identified 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 downregulates 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 plays a significant role in regulating the SCF complex by controlling its ubiquitin ligase activities and its rubylation cycle.