p57 Phosphorylation Modulates Its Localization, Stability, and Interactions.

p57 is a member of the cyclin-dependent kinase (CDK) Interacting Protein/Kinase Inhibitory Protein (CIP/Kip) family that also includes p21 and p27. Different from its siblings, few data are available about the p57 protein, especially in humans. Structurally, p57 is an intrinsically unstructured protein, a characteristic that confers functional flexibility with multiple transient interactions influencing the metabolism and roles of the protein.