Protecting your tail: regulation of cadherin degradation by p120-catenin

Work in various model systems has yielded conflicting views of how p120-catenin participates in adherens junction assembly and regulation. A series of recent studies indicate that a core function of p120-catenin in mammalian cells is to regulate cadherin turnover by modulating the entry of cadherins into degradative endocytic pathways. By this mechanism, cellular levels of p120-catenin perform a 'rheostat' or 'set point' function that controls steady-state cadherin levels. These studies parallel a growing interest in the regulation of cadherin levels at the cell surface by membrane trafficking pathways. Collectively, the findings suggest exciting new roles for p120-catenin at the interface between cadherins and membrane trafficking machinery, and imply novel mechanisms by which p120-catenin may regulate cell adhesion and migration in the context of development and cancer.