title: Detection of Transglutaminase 2 conformational changes in living cell.
abstract: Transglutaminase 2 (TG2) is a ubiquitous Ca(2+)-dependent protein cross-linking enzyme that is implicated in a variety of biological disorders. In in vitro experiments when Ca(2+) concentration was increased TG2 changed its conformation and was able to cross-link other proteins via formation of an isopeptide bond. However the mechanisms that regulate TG2 transamidation activity in cells are still unknown. In this study we have developed FRET-based method for monitoring TG2 conformation changes and, probably, cross-linking activity in living cells. Using this approach we have showed that a significant amount of TG2 within the cell is accumulated in perinuclear endosomes and has a cross-linking inactive conformation, while TG2 that is located beneath the cell membrane has a transamidation active conformation. After the induction of apoptosis cytoplasmic TG2 changed its conformation and activates while, TG2 in endosomes retained transamidation inactive conformation even at late stages of apoptosis.
authors.affiliation: Shemiakin-Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Moscow 117997, Russian Federation.
authors.forename: Marat S
authors.initials: MS
authors.lastname: Pavlyukov
authors.forename: Nadezhda V
authors.initials: NV
authors.lastname: Antipova
authors.forename: Maria V
authors.initials: MV
authors.lastname: Balashova
authors.forename: Mikhail I
authors.initials: MI
authors.lastname: Shakhparonov
mesh_terms: D017209:Apoptosis; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D004705:Endocytosis; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D019204:GTP-Binding Proteins / Q000737:chemistry*; D006801:Humans; D008247:Lysosomes / Q000201:enzymology; D011487:Protein Conformation; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D059748:Proteolysis; D011503:Transglutaminases / Q000737:chemistry*
chemical_list: D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins