title: Cell cycle regulation by the intrinsically disordered proteins p21 and p27.
abstract: Today, it is widely accepted that proteins that lack highly defined globular three-dimensional structures, termed IDPs (intrinsically disordered proteins), play key roles in myriad biological processes. Our understanding of how intrinsic disorder mediates biological function is, however, incomplete. In the present paper, we review disorder-mediated cell cycle regulation by two intrinsically disordered proteins, p21 and p27. A structural adaptation mechanism involving a stretchable dynamic linker helix allows p21 to promiscuously recognize the various Cdk (cyclin-dependent kinase)-cyclin complexes that regulate cell division. Disorder within p27 mediates transmission of an N-terminal tyrosine phosphorylation signal to a C-terminal threonine phosphorylation, constituting a signalling conduit. These mechanisms are mediated by folding upon binding p21/p27's regulatory targets. However, residual disorder within the bound state contributes critically to these functional mechanisms. Our studies provide insights into how intrinsic protein disorder mediates regulatory processes and opportunities for designing drugs that target cancer-associated IDPs.
authors.affiliation: St. Jude Children's Research Hospital, Department of Structural Biology, 262 Danny Thomas Place, Memphis TN, 38105, U.S.A.
authors.forename: Mi-Kyung
authors.initials: MK
authors.lastname: Yoon
authors.forename: Diana M
authors.initials: DM
authors.lastname: Mitrea
authors.forename: Li
authors.initials: L
authors.lastname: Ou
authors.forename: Richard W
authors.initials: RW
authors.lastname: Kriwacki
mesh_terms: D002453:Cell Cycle; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000737:chemistry / Q000378:metabolism*; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27