title: Phosphatidylethanolamine-binding proteins, including RKIP, exhibit affinity for phosphodiesterase-5 inhibitors.
abstract: Identifying protein "interactors" of drugs is of great importance to understand their mode of action and possible cross-reactivity to off-target protein binders. In this study, we profile proteins that bind to PF-3717842, a high-affinity phosphodiesterase-5 (PDE5) inhibitor, by using a refined affinity pulldown approach with PF-3717842 immobilized beads. By performing these pulldowns in rat testis tissue lysate, we strongly and specifically enriched for PDE5 and a few other PDEs. In addition to these expected affinity-enriched proteins we also detect rodent-specific phosphatidylethanolamine-binding protein 2 (PEBP2), as a putative binder to the PDE5 inhibitor. By using recombinant forms of the related murine mPEBP2, mPEBP1 and human hPEBP1 (also known as Raf kinase inhibitor protein or RKIP) we confirm that they all can bind strongly to immobilized as well as soluble PF-3717842. As the phosphatidylethanolamine-binding proteins are involved in various important signal transduction pathways, the synthetic PDE5 inhibitor used here might form a platform to synthesize enhanced binders/inhibitors of the family of PEBP proteins. Our approach shows how chemical proteomics might be used to profile the biochemical space (interactome) of small molecule inhibitors.
authors.affiliation: Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, NL.
authors.forename: Poupak
authors.initials: P
authors.lastname: Dadvar
authors.forename: Duangnapa
authors.initials: D
authors.lastname: Kovanich
authors.forename: Gert E
authors.initials: GE
authors.lastname: Folkers
authors.forename: Klaus
authors.initials: K
authors.lastname: Rumpel
authors.forename: Reinout
authors.initials: R
authors.lastname: Raijmakers
authors.forename: Albert J R
authors.initials: AJ
authors.lastname: Heck
mesh_terms: D000595:Amino Acid Sequence; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010714:Phosphatidylethanolamines / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000187:drug effects
chemical_list: D010714:Phosphatidylethanolamines; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors