Erregistroa posta elektronikoz bidali: Degradation of p21(Cip1) through Anaphase-promoting Complex/Cyclosome and Its Activator Cdc20 (APC/C(Cdc20)) Ubiquitin Ligase Complex-mediated Ubiquitylation Is Inhibited by Cyclin-dependent Kinase 2 in Cardiomyocytes