(A) Cx50 de-stabilizes Skp2 at the mitotic phase. The protein level was quantified and normalized to 0 hr.
(B) Cx50 delays the increased expression of Skp2 during cell-cycle progression. The level of protein was quantified and normalized to 0 hr.
(C) The reduction of Skp2 by Cx50 is not affected by p27 siRNA.
(D) Cx50 increases ubiquitination level of Skp2. The protein expression levels were examined with western blotting (lower).
(E) Cx50 has no effect on the association of Skp2 with Skp1, but disrupts Skp1/2 interaction with importin-7 and Cdh1.
(F) Cx50 C terminus increases auto-ubiquitination of Skp2 in vitro. SCFSkp2 complex was used for in vitro ubiquitination assay with isolated GST-fusion containing WT or V362E mutant of Cx50 C terminus or GST. The specificity of the assay was validated containing all assay-required materials except Mg-ATP, ubiquitin (Ub) or E1/E2 enzymes, respectively.
See also Figure S5.