Cdc20 And Cdh1 Mediated Sp100 Protein Degradation Mechanism

Cdc20 and Cdh1 are the co-activators of the APC/C complex. They can activate the APC/C and present substrates at the particular cycle phase, Cdc20 at most time of the mitosis and Cdh1 at telophase and G0/G1 phase, and then mediate the degradation of the substrates. Sp100 is one scaffold protein of PML-NBs, participating in kinds of important cellular activities which include anti virus, transcriptional regulation and apoptosis. Here in this article, we proved that Cdc20 and Cdh1 mediated the destruction of Sp100 through the ubiquitination pathway, and intact D-box was required. It is interesting to find that the amounts of both the Sp100 mRNA and protein remained at almost similar level, unlike other Cdc20 and Cdhl substrates which possess of oscillating protein expressions. These clues imply a new Sp100 protein regulation mechanism and offer us important hints to find out the relationship between cycle-related Cdc20, Cdh1 and other PML-NBs proteins.