PIN1 and telomere syndrome: Accordingly, we hypothesized that the increased expression of YPEL3 by STS deficiency is regulated by ER signaling, and the decrease in ERα protein levels may occur through regulation of factors affecting ERα protein stability such as mucin 1 (MUC1), protein interacting with never in mitosis A (PIN1), glycogen synthase kinase-3 (GSK3), and ring finger protein 31 (RNF31)34–39.