CELLULAR STRESS CAUSES ACCUMULATION OF THE GLUCOSE-TRANSPORTER AT THESURFACE OF CELLS INDEPENDENTLY OF THEIR INSULIN SENSITIVITY

The stimulation of glucose transport in response to various types of s tress has been studied. There is no relationship between effects of st ress-inducing agents on glucose transport and their effects on cellula r protein synthesis. Although the effect of stress on glucose transpor t appears analogous to its stimulation by insulin, cells that are slig htly insulin-sensitive in terms of glucose transport (BHK cells) show a similar degree of stimulation as highly insulin-sensitive cells (dif ferentiated 3T3-L1 cells). External labeling of the transporter protei n with a photoactivatable derivative of mannose, 2-N-4-(1-azi-2,2,2-tr ifluoroethyl) benzoyl-1, 3-bis-(D-mannos-4-yloxy)-propylamine, shows t hat most of the increased glucose transport activity correlates with a n increase in the amount of the transporter on the cell surface. Cells subjected to K+-depletion, which inhibits endocytosis and results in an accumulation of receptors at the cell surface, show the same increa se in glucose transport as cells exposed to stress; stressed cells sho w no further increase in glucose transport when subjected to K+ deplet ion. These results support the view (Widnell, C.C., Baldwin, S.A., Dav ies, A., Martin, S., Pasternak, C.A. 1990. FASEB J 4:1634-1637) that c ellular stress increases glucose transport by promoting the accumulati on of glucose transporter molecules at the cell surface.