From Proteopediaproteopedia link
Selective targeting of disease-relevant protein binding domains by O-phosphorylated natural product derivatives
[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
Phosphorylation-dependent protein binding domains are crucially important for intracellular signaling pathways and thus highly relevant targets in chemical biology. By screening of chemical libraries against 12 structurally diverse phosphorylation-dependent protein binding domains, we have identified fosfosal and dexamethasone-21-phosphate as selective inhibitors of two antitumor targets: the SH2 domain of the transcription factor STAT5b and the substrate-binding domain of the peptidyl-prolyl isomerase Pin1, respectively. Both compounds are phosphate prodrugs with documented clinical use as anti-inflammatory agents in humans and were discovered with a high hit rate from a small subgroup within the screening library. Our study indicates O-phosphorylation of appropriately preselected natural products or natural product derivatives as a generally applicable strategy for the identification of non-reactive and non-peptidic ligands of phosphorylation-dependent protein binding domains. Moreover, our data indicate that it would be advisable to monitor the bioactivities of clinically used prodrugs in their uncleaved state against phosphorylation-dependent protein binding domains.
Selective Targeting of Disease-Relevant Protein Binding Domains by O-Phosphorylated Natural Product Derivatives.,Graber M, Janczyk W, Sperl B, Elumalai N, Kozany C, Hausch F, Holak TA, Berg T ACS Chem Biol. 2011 Aug 10. PMID:21797253
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.