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STRUCTURAL BASIS FOR THE PHOSPHOSERINE-PROLINE RECOGNITION BY GROUP IV WW DOMAINS
[PIN1_HUMAN] Essential PPIase that regulates mitosis presumably by interacting with NIMA and attenuating its mitosis-promoting activity. Displays a preference for an acidic residue N-terminal to the isomerized proline bond. Catalyzes pSer/Thr-Pro cis/trans isomerizations. Down-regulates kinase activity of BTK. Can transactivate multiple oncogenes and induce centrosome amplification, chromosome instability and cell transformation. Required for the efficient dephosphorylation and recycling of RAF1 after mitogen activation.  
Publication Abstract from PubMed
Pin1 contains an N-terminal WW domain and a C-terminal peptidyl-prolyl cis-trans isomerase (PPIase) domain connected by a flexible linker. To address the energetic and structural basis for WW domain recognition of phosphoserine (P.Ser)/phosphothreonine (P. Thr)- proline containing proteins, we report the energetic and structural analysis of a Pin1-phosphopeptide complex. The X-ray crystal structure of Pin1 bound to a doubly phosphorylated peptide (Tyr-P.Ser-Pro-Thr-P.Ser-Pro-Ser) representing a heptad repeat of the RNA polymerase II large subunit's C-terminal domain (CTD), reveals the residues involved in the recognition of a single P.Ser side chain, the rings of two prolines, and the backbone of the CTD peptide. The side chains of neighboring Arg and Ser residues along with a backbone amide contribute to recognition of P.Ser. The lack of widespread conservation of the Arg and Ser residues responsible for P.Ser recognition in the WW domain family suggests that only a subset of WW domains can bind P.Ser-Pro in a similar fashion to that of Pin1.
Structural basis for phosphoserine-proline recognition by group IV WW domains.,Verdecia MA, Bowman ME, Lu KP, Hunter T, Noel JP Nat Struct Biol. 2000 Aug;7(8):639-43. PMID:10932246
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.