(A) Phosphorylation of Bcl-2 associated agonist of cell death (Bad) at Ser112, Ser136, and Ser155 reveals activation of the intrinsic apoptosis pathway. pBad (Ser112) was decreased in the cyclin F variants K97R (0.385-fold, p = 0.0001, n = 4), S195R (0.529-fold), S509P (0.413-fold), and S621G (0.508-fold) when compared to the cyclin F wild-type control (one-way ANOVA with Dunnett’s multiple comparison test, n = 4). pBad (Ser155) was decreased in only S195R (0.616-fold), S509 (0.578-fold), and R574Q (0.37-fold) when compared to the cyclin F wild-type control (one-way ANOVA with Dunnett’s multiple comparison test, n = 4). (B) Immunoblot analysis of Bcl-2, Bax, and SOD1 from cells expressing cyclin F wild-type and variants (K97R, S195R, S509P, R574Q, S621G) reveals increased Bax/Bcl-2 ratios in K97R (1.53-fold), S509P (1.58-fold), and S621G (1.55-fold) (one-way ANOVA with Dunnet’s multiple comparison test, n = 3) suggesting increased stimulation of apoptosis.
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