title: Distinct characteristic of Galpha(h) (transglutaminase II) by compartment: GTPase and transglutaminase activities.
abstract: Galpha(h) (transglutaminase II) is a bifunctional enzyme possessing transglutaminase and GTPase activities. To better understand the factors affecting these two functions of Galpha(h), we have examined the characteristics of purified Galpha(h) from membrane and cytosol. GTP binding activity of mouse heart Galpha(h) was higher in membrane than that from cytosol. Furthermore, phospholipase C-delta1 (PLC-delta1) activity and coimmunoprecipitation of Galpha(h)-coupled PLC-delta1 in the alpha(1)-adrenoceptor-Galpha(h)-PLC-delta1 complex preparations were increased by phenylephrine in the presence of membranous Galpha(h). On the other hand, transglutaminase activity of cytosolic Galpha(h) was higher than that from membrane Galpha(h). These results demonstrate that bifunctions of Galpha(h) are regulated by its localization that can reflect the cellular functions of Galpha(h).
authors.affiliation: Institute of Medical Science, Department of Biochemistry, College of Medicine, Chung-Ang University, 221 Heuksuk-Dong, Dongjak-Ku, Seoul, 156-756, Republic of Korea.
authors.forename: H
authors.initials: H
authors.lastname: Park
authors.forename: E S
authors.initials: ES
authors.lastname: Park
authors.forename: H S
authors.initials: HS
authors.lastname: Lee
authors.forename: H Y
authors.initials: HY
authors.lastname: Yun
authors.forename: N S
authors.initials: NS
authors.lastname: Kwon
authors.forename: K J
authors.initials: KJ
authors.lastname: Baek
mesh_terms: D000818:Animals; D019556:COS Cells; D002118:Calcium / Q000494:pharmacology; D002451:Cell Compartmentation / Q000502:physiology*; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology; D051379:Mice; D008813:Mice, Inbred ICR; D009206:Myocardium / Q000201:enzymology; D010656:Phenylephrine / Q000494:pharmacology; D054803:Phospholipase C delta; D011233:Precipitin Tests; D011485:Protein Binding / Q000187:drug effects; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014162:Transfection; D011503:Transglutaminases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D046911:Macromolecular Substances; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D010738:Type C Phospholipases; D054803:Phospholipase C delta; C518025:Plcd1 protein, mouse; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D008274:Magnesium; D002118:Calcium