title: Cholecystokinin stimulates heat shock protein 27 phosphorylation in rat pancreas both in vivo and in vitro.
abstract: OBJECTIVE
  Mammalian heat shock protein 27 (hsp27) is believed to function under normal physiological conditions and during cellular stress. Recent studies indicate a role for hsp27 in regulating actin-cytoskeletal dynamics. In the present study, secretagogue-regulated phosphorylation of hsp27 in rat exocrine pancreas was investigated both in vivo and in isolated acinar cells.
  
  
  METHODS
  Western analysis after two-dimensional electrophoresis was used to measure the phosphorylation of hsp27 after treatment of rats or acinar cells with secretagogues. Cholecystokinin-stimulated mitogen-activated protein kinase-activated protein (MAPKAP) kinase 2 activity was measured after immunoprecipitation of the kinase.
  
  
  RESULTS
  hsp27 exists as three isoforms in acini: one nonphosphorylated (pI 6.2) and two phosphorylated (pIs 5.9 and 5.7) forms. Infusion of rats with a secretory or supermaximal dose of cerulein produced an acidic shift in hsp27, indicating an increase in its phosphorylation; the higher dose, known to cause pancreatitis, had a twofold greater effect. In isolated acini, increases in hsp27 phosphorylation were evident at 10 pmol/L and maximal at 1 nmol/L cholecystokinin. The hsp27-specific kinase MAPKAP kinase 2 was activated 2.4-fold with 1 nmol/L cholecystokinin treatment.
  
  
  CONCLUSIONS
  hsp27 phosphorylation was stimulated by low and high concentrations of cholecystokinin, both in vivo and in vitro. Phosphorylation was potentially mediated via the MAPKAP kinase 2 intracellular signaling pathway.
authors.affiliation: Department of Physiology, University of Michigan Medical School, Ann Arbor 48109-0622, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Groblewski
authors.forename: T
authors.initials: T
authors.lastname: Grady
authors.forename: N
authors.initials: N
authors.lastname: Mehta
authors.forename: H
authors.initials: H
authors.lastname: Lambert
authors.forename: C D
authors.initials: CD
authors.lastname: Logsdon
authors.forename: J
authors.initials: J
authors.lastname: Landry
authors.forename: J A
authors.initials: JA
authors.lastname: Williams
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002766:Cholecystokinin / Q000494:pharmacology*; D004789:Enzyme Activation; D006360:Heat-Shock Proteins / Q000378:metabolism*; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D002766:Cholecystokinin; D006360:Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D000099190:MAP-Kinase-Activated Kinase 2