CDK5 activator p35 downregulates E-cadherin precursor independently of CDK5

Dysfunction of E-cadherins often results in metastasis of cancerous cells. Here we show that p35, a critical regulator of cyclin-dependent kinase 5 (CDK5), specifically depletes the precursor form of E-cadherin, but not the mature form, by using a precursor-specific antibody. Most intriguingly, this downregulation of precursor E-cadherin by p35 is unequivocally independent of CDK5. Moreover, we found that p35 forms complexes with E-cadherin proteins. We also found that p35 co-expression can target E-cadherin to lysosomes and that p35-triggered disappearance of E-cadherin precursor can be blocked specifically by lysosomal protease inhibitors, indicating that p35 induces endocytosis and subsequent degradation of precursor E-cadherin.Structured summaryMINT-6276674, MINT-6276685:E-cadherin (uniprotkb:P09803) physically interacts (MI:0218) with p35 (uniprotkb:P61809) by coimmunoprecipitation (MI:0019)MINT-6276701, MINT-6276714:Cdk5 (uniprotkb:P49615) physically interacts (MI:0218) with p35 (uniprotkb:P61809) by coimmunoprecipitation (MI:0019)