title: Phoslactomycin targets cysteine-269 of the protein phosphatase 2A catalytic subunit in cells.
abstract: According to the chemical genetic approach, small molecules that bind directly to proteins are used to analyze protein function, thereby enabling the elucidation of complex mechanisms in mammal cells. Thus, it is very important to identify the molecular targets of compounds that induce a unique phenotype in a target cell. Phoslactomycin A (PLMA) is known to be a potent inhibitor of protein Ser/Thr phosphatase 2A (PP2A); however, the inhibitory mechanism of PP2A by PLMA has not yet been elucidated. Here, we demonstrated that PLMA directly binds to the PP2A catalytic subunit (PP2Ac) in cells by using biotinylated PLMA, and the PLMA-binding site was identified as the Cys-269 residue of PP2Ac. Moreover, we revealed that the Cys-269 contributes to the potent inhibition of PP2Ac activity by PLMA. These results suggest that PLMA is a PP2A-selective inhibitor and is therefore expected to be useful for future investigation of PP2A function in cells.
authors.affiliation: Antibiotics Laboratory, Discovery Research Institute, RIKEN, Wako, Saitama, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Teruya
authors.forename: Siro
authors.initials: S
authors.lastname: Simizu
authors.forename: Naoki
authors.initials: N
authors.lastname: Kanoh
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Osada
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D019921:Biotinylation; D020134:Catalytic Domain; D002460:Cell Line; D003545:Cysteine / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007783:Lactones / Q000737:chemistry / Q000494:pharmacology*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009943:Organophosphorus Compounds / Q000737:chemistry / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000145:classification / Q000378:metabolism; D054648:Protein Phosphatase 2; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D011753:Pyrones; D016415:Sequence Alignment
chemical_list: D004791:Enzyme Inhibitors; D007783:Lactones; D009943:Organophosphorus Compounds; D021122:Protein Subunits; D011753:Pyrones; C060448:phoslactomycin A; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D003545:Cysteine