title: The nucleolar phosphoprotein P130 is a GTPase/ATPase with intrinsic property to form large complexes triggered by F- and Mg2+.
abstract: We have previously identified a human nucleolar phosphoprotein p130 whose alterations during mitosis are correlated well with the nucleolar disassembly and reassembly. Further studies found that p130 in the cell lysates or after being purified by immunoprecipitation was able to form large complexes triggered by F- and Mg2+. These sodium dodecyl sulfate-insoluble p130 molecules were readily dissociated by adding EDTA to the complexes. It is known that F- and Mg2+ act on many GTPases and ATPases through the induction of a conformational transition mimicking the nucleoside triphosphate-bound state. These initial observations led us to discover that p130 functions as a GTP/ATP binding protein with intrinsic GTPase/ATPase activities. The rate of GTP hydrolysis by purified p130 under our experimental conditions was 0.8 mol/min/mol of p130. These results imply that p130, a novel nucleolar GTPase/ATPase, may switch its conformation in a nucleotide-dependent manner.
authors.affiliation: Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan, Republic of China.
authors.forename: H K
authors.initials: HK
authors.lastname: Chen
authors.forename: N H
authors.initials: NH
authors.lastname: Yeh
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D001345:Autoradiography; D004591:Electrophoresis, Polyacrylamide Gel; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D012969:Sodium Fluoride / Q000494:pharmacology*
chemical_list: D009687:Nuclear Proteins; D010750:Phosphoproteins; D010761:Phosphorus Radioisotopes; C095383:nucleolar phosphoprotein p130; D015636:Magnesium Chloride; D000255:Adenosine Triphosphate; D012969:Sodium Fluoride; D000251:Adenosine Triphosphatases; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins