Bombesin stimulation of p125 focal adhesion kinase tyrosine phosphorylation. Role of protein kinase C, Ca2+ mobilization, and the actin cytoskeleton.

摘要: Activation of protein kinase C (PKC) in quiescent Swiss 3T3 cells using either the tumor promoter phorbol 12,13-dibutyrate (PDB) or diacylglycerols increased tyrosine phosphorylation p125 focal adhesion (p125FAK) by 3.8-fold. PDB stimulation p125FAK was detected within 1 min and reached a maximum 5 min, considerably slower than 80K/MARCKS which maximal min. In sharp contrast, bombesin-induced (8-fold stimulation) after addition peptide occurred with half-maximal effect 0.08 nM, 6-fold lower bombesin on phosphorylation. Down-regulation PKC prolonged treatment blocked but had no response to bombesin. A selective inhibitor PKC, GF 109203X, markedly inhibited little bombesin, vasopressin, endothelin. Bombesin could also be dissociated from mobilization Ca2+ intracellular stores. Depletion pool thapsigargin completely ability transiently increase cytosolic concentration cytochalasin D, an agent selectively disrupts network actin microfilaments, bombesin- PDB-induced Within same range (0.3-2 microM), drug other early events stimulated including activation PKC. These findings demonstrate that neither nor pathways are responsible for rapid neuropeptide growth factors. Furthermore, integrity cytoskeleton is essential effects both