Cholecystokinin rapidly stimulates CrkII function in vivo in rat pancreatic acini. Formation of CrkII-protein complexes.
Crk belongs to a family of adapter proteins whose structure allows interaction with tyrosine-phosphorylated proteins and is therefore an important modulator of downstream signals, representing a convergence of the actions of numerous stimuli. Recently, it was demonstrated that cholecystokinin (CCK) induced tyrosine phosphorylation of proteins related to fiber stress formation in rat pancreatic acini. Here, we investigated whether CCK receptor activation signals through CrkII and forms complexes with tyrosine-phosphorylated proteins in rat pancreatic acini. We demonstrated that CCK promoted the transient formation of CrkII-paxillin and CrkII-p130Cas complexes with maximal effect at 1 min. Additionally, CCK decreased the electrophoretic mobility of CrkII. This decrease was time- and concentration-dependent and inversely related with its function. Carbachol and bombesin also decreased CrkII electrophoretic mobility, whereas epidermal growth factor, vasoactive intestinal peptide, secretin or pituitary adenylate cyclase-activating polypeptide had no effect. CCK-induced CrkII electrophoretic shift was dependent on the Src family of tyrosine kinases and occurred in the intact animal, suggesting a physiological role of CrkII mediating CCK actions in the exocrine pancreas in vivo.
Andreolotti
Alberto G
AG
Departamento de Fisiologia, Universidad de Extremadura, Caceres, Spain.
Bragado
Maria J
MJ
Tapia
Jose A
JA
Jensen
Robert T
RT
Garcia-Marin
Luis J
LJ
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002766:Cholecystokinin / Q000494:pharmacology*; D050719:Crk-Associated Substrate Protein; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008297:Male; D010179:Pancreas / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011506:Proteins; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000378:metabolism*; D050737:Proto-Oncogene Proteins c-crk; D051381:Rats; D017208:Rats, Wistar; D050717:Retinoblastoma-Like Protein p130; D012844:Sincalide / Q000494:pharmacology; D013997:Time Factors
C493843:Bcar1 protein, rat; C493872:Crk protein, rat; D050719:Crk-Associated Substrate Protein; D003598:Cytoskeletal Proteins; D046911:Macromolecular Substances; D051419:Paxillin; D010750:Phosphoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D050737:Proto-Oncogene Proteins c-crk; C496063:Pxn protein, rat; D050717:Retinoblastoma-Like Protein p130; D019000:Phosphotyrosine; D002766:Cholecystokinin; D012844:Sincalide; D002118:Calcium