Potential role of Gab1 and phospholipase C-gamma in osmotic shock-induced glucose uptake in 3T3-L1 adipocytes.
Osmotic shock induces GLUT4 translocation and glucose uptake through a mechanism independent of PI 3-kinase, but dependent on tyrosine phosphorylation of cellular proteins. To identify the tyrosine phosphorylated proteins required for osmotic shock-stimulated glucose uptake, we examined tyrosine phosphorylation of candidate proteins, and found that the 60-80kDa species including paxillin and the 120-130kDa species including p130Cas, PYK2, FAK and Gab1 were tyrosine-phosphorylated in response to osmotic shock. Inhibition of actin polymerization by cytochalasin D significantly decreased the tyrosine phosphorylation of paxillin, p130Cas, PYK2 and FAK but not Gab1, but had no effect on 2-deoxyglucose (DOG) uptake, suggesting a role for Gab1 in osmotic shock-induced glucose transport. Also, we found that osmotic shock increases the association of phospholipase C-gamma (PLC-gamma) with Gab1 and stimulates tyrosine phosphorylation of PLC-gamma itself. The PLC inhibitor, U73122, inhibited osmotic shock-induced 2-DOG uptake. These results suggest that tyrosine phosphorylation of Gab1 and subsequent recruitment and activation of PLC-gamma may play a role in osmotic shock-induced glucose transport.
Ueno
E
E
First Department of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Haruta
T
T
Uno
T
T
Usui
I
I
Iwata
M
M
Takano
A
A
Kawahara
J
J
Sasaoka
T
T
Ishibashi
O
O
Kobayashi
M
M
D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D015638:Cytochalasin D / Q000494:pharmacology; D003847:Deoxyglucose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D015151:Immunoblotting; D007527:Isoenzymes / Q000502:physiology*; D051379:Mice; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D009997:Osmotic Pressure; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051966:Phospholipase C gamma; D010750:Phosphoproteins / Q000502:physiology*; D010766:Phosphorylation; D011233:Precipitin Tests; D010738:Type C Phospholipases / Q000502:physiology*; D014443:Tyrosine / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D015638:Cytochalasin D; D003847:Deoxyglucose; D005947:Glucose; D007527:Isoenzymes; D019384:Nucleic Acid Synthesis Inhibitors; D019869:Phosphatidylinositol 3-Kinases; D051966:Phospholipase C gamma; D010750:Phosphoproteins; D010738:Type C Phospholipases; D014443:Tyrosine; C490897:Gab1 protein, mouse