title: A conserved motif mediates both multimer formation and allosteric activation of phosphoglycerate mutase 5.
abstract: Phosphoglycerate mutase 5 (PGAM5) is an atypical mitochondrial Ser/Thr phosphatase that modulates mitochondrial dynamics and participates in both apoptotic and necrotic cell death. The mechanisms that regulate the phosphatase activity of PGAM5 are poorly understood. The C-terminal phosphoglycerate mutase domain of PGAM5 shares homology with the catalytic domains found in other members of the phosphoglycerate mutase family, including a conserved histidine that is absolutely required for catalytic activity. However, this conserved domain is not sufficient for maximal phosphatase activity. We have identified a highly conserved amino acid motif, WDXNWD, located within the unique N-terminal region, which is required for assembly of PGAM5 into large multimeric complexes. Alanine substitutions within the WDXNWD motif abolish the formation of multimeric complexes and markedly reduce phosphatase activity of PGAM5. A peptide containing the WDXNWD motif dissociates the multimeric complex and reduces but does not fully abolish phosphatase activity. Addition of the WDXNWD-containing peptide in trans to a mutant PGAM5 protein lacking the WDXNWD motif markedly increases phosphatase activity of the mutant protein. Our results are consistent with an intermolecular allosteric regulation mechanism for the phosphatase activity of PGAM5, in which the assembly of PGAM5 into multimeric complexes, mediated by the WDXNWD motif, results in maximal activation of phosphatase activity. Our results suggest the possibility of identifying small molecules that function as allosteric regulators of the phosphatase activity of PGAM5.
authors.affiliation: From the Bond Life Sciences Center and.
authors.forename: Jordan M
authors.initials: JM
authors.lastname: Wilkins
authors.affiliation: From the Bond Life Sciences Center and.
authors.forename: Cyrus
authors.initials: C
authors.lastname: McConnell
authors.affiliation: the Department of Biochemistry, University of Missouri, Columbia, Missouri 65211.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Tipton
authors.affiliation: From the Bond Life Sciences Center and the Department of Biochemistry, University of Missouri, Columbia, Missouri 65211 hanninkm@missouri.edu.
authors.forename: Mark
authors.initials: M
authors.lastname: Hannink
mesh_terms: D000494:Allosteric Regulation; D020816:Amino Acid Motifs / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D002850:Chromatography, Gel; D017124:Conserved Sequence / Q000235:genetics*; D004789:Enzyme Activation; D015151:Immunoblotting; D007700:Kinetics; D051379:Mice; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010748:Phosphopeptides / Q000737:chemistry / Q000378:metabolism; D010749:Phosphoprotein Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization / Q000235:genetics*; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
chemical_list: D010748:Phosphopeptides; C570696:PGAM5 protein, mouse; D010749:Phosphoprotein Phosphatases; D010744:Phosphoric Monoester Hydrolases
keywords: Allosteric Regulation; Enzyme Kinetics; Mitochondria; Protein Cross-linking; Protein Motif; Protein Self-assembly; Protein Serine/Threonine Phosphatase (PSP)