Supplementary Figures 1 through 13 from Cdk5 Directly Targets Nuclear p21<sup>CIP1</sup> and Promotes Cancer Cell Growth

Figure S1. Cdk5 activity is correspondent to itself protein level and type. Figure S2. The analysis of Cdk5 and p21CIP1protein levels in the specimens of breast cancer patients. Figure S3. Representative images of immunohistochemicalstaining. Figure S4. Inhibition of proteasome activity by lactacystinrestores Cdk5-triggered p21CIP1protein decrease. Figure S5. The proteasome inhibitors, MG132 and Lactacystin, do not influence the trends of p21CIP1mRNA levels regulated by different statuses of Cdk5 activation. Figure S6. The efficiency test of different clones of shCdk5and shCdk2 in cancer cells and the knockdown efficiency of shCdk2in xenograft tumors. Figure S7. The nuclear levels of p21CIP1protein were increased by Cdk5 knockdown. Figure S8. The protein levels of Cdk5 and p21CIP1transient transfections in MCF-7 cells for the reference of Figure 5B. Figure S9. Nuclear S130A p21CIP1is resistant to Cdk5-induced degradation. Figure S10. Cdk5-induced p21CIP1degradation is ubiquitination-independent. Figure S11. Cdk5 enables to decrease p21 protein with or without Aktinhibition. Figure S12. Cdk5 activity is not essential to its protein interaction with p21CIP1. Figure S13. Nuclear S130A p21CIP1is tightly interacted with Cdk5 in nucleus.