Cyclin-dependent kinase inhibitor 1, also known as CDK-interacting protein 1, or more simply as p21, is a cell cycle inhibitor that promotes both CDK/cyclin inhibition as well as cell cycle arrest ...

Multiple transcription factors, ubiquitin ligases, and protein kinases regulate ... in our understanding of the regulation of p21 and its biological functions with emphasis on its p53-independent ...

just as Kriwacki’s p21 did. The skeptics thought that any disordered proteins had to be one-offs—outliers—and that the classical structure-function dogma held. “Our answer to that was ...