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Selected Publication:
SHR Neuro Cancer Cardio Lipid Metab Microb
Hoffmann, KM; Tapia, JA; Jensen, RT.
Activation of Gab1 in pancreatic acinar cells: effects of gastrointestinal growth factors/hormones on stimulation, phosphospecific phosphorylation, translocation and interaction with downstream signaling molecules.
Cell Signal. 2006; 18(7):942-954
Doi: 10.1016/j.cellsig.2005.08.013
Web of Science
PubMed
FullText
FullText_MUG
- Leading authors Med Uni Graz
- Hoffmann Karl Martin
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- Abstract:
- The scaffolding/adapter protein, Gab1, is a key signaling molecule for numerous stimuli including growth factors and G protein-coupled-receptors (GPCRs). A number of questions about Gab1 signaling remain and little is known about the ability of gastrointestinal (GI) hormones/neurotransmitters/growth factors to activate Gab1. Therefore, we examined their ability to activate Gab1 and explored the mechanisms involved using rat pancreatic acini. HGF and EGF stimulated total Gab1 tyrosine phosphorylation (TyrP) and TyrP of Gab1 phospho-specific sites (Y307, Y627), but not other pancreatic growth factors, GI GPCRs (CCK, bombesin, carbachol, VIP, secretin), or agents directly activating PKC or increasing Ca2+. HGF-stimulated Y307 Gab1 TyrP differed in kinetics from total and Y627. Neither GF109203X, nor inhibition of Ca2+ increases altered HGF's effect. In unstimulated cells>95% of Gab1 was cytosolic and HGF stimulated a 3-fold increase in membrane Gab1. HGF stimulated equal increases in pY307 and pY627 Gab1 in cytosol/membrane. HGF stimulated Gab1 association with c-Met, Grb2, SHP2, PI3K, Shc, Crk isoforms and CrkL, but not with PLCgamma1. These results demonstrate that only a subset of pancreatic growth factors (HGF/EGF) stimulates Gab1 signaling and no pancreatic hormones/neurotransmitters. Our results with Gab1 activation with different growth factors, the role of PKC, and its interaction with distant signaling molecules suggest the cellular mechanisms of Gab1 signaling show important differences in different cells. These results show that Gab1 activation plays a central role in HGF's ability to stimulate intracellular transduction cascades in pancreatic acinar cells and this action likely plays a key role in HGF's ability to alter pancreatic cell function (i.e., growth/regeneration).
- Find related publications in this database (using NLM MeSH Indexing)
- Animals -
- Calcium - metabolism
- Cell Membrane - metabolism
- Cyclic AMP-Dependent Protein Kinases - metabolism
- Enzyme Activation - metabolism
- Epidermal Growth Factor - physiology
- Gastrointestinal Hormones - physiology
- Growth Substances - physiology
- Hepatocyte Growth Factor - physiology
- In Vitro - physiology
- Male - physiology
- Pancreas - cytology
- Phosphoproteins - biosynthesis
- Phosphorylation - biosynthesis
- Protein Kinase C - metabolism
- Protein Transport - metabolism
- Rats - metabolism
- Rats, Sprague-Dawley - metabolism
- Signal Transduction - metabolism
- Tyrosine - metabolism
- Find related publications in this database (Keywords)
- Gab1 pancreas
- pancreatic growth factors
- pancreatic secretagogues
- cholecystokinin
- hepatocyte growth factor
- tyrosine phosphorylation