Identification of a function-specific mutation of clathrin heavy chain (CHC) required for p53 transactivation.

The p53 pathway is activated in response to various cellular stresses to protect cells from malignant transformation. We have previously shown that clathrin heavy chain (CHC), which is a cytosolic protein regulating endocytosis, is present in nuclei and binds to p53 to promote p53-mediated transcription. However, details of the binding interface between p53 and CHC remain unclear. Here, we report on the binding mode between p53 and CHC using mutation analyses and a structural model of the interaction generated by molecular dynamics. Structural modeling analyses predict that an Asn1288 residue in CHC is crucial for binding to p53. In fact, substitution of this Asn to Ala of CHC diminished its ability to interact with p53, leading to reduced activity to transactivate p53. Surprisingly, this mutation had little effect on receptor-mediated endocytosis. Thus, the function-specific mutation of CHC will clarify physiological roles of CHC in the regulation of the p53 pathway.