Regulation of glut! in response to cellular stress

A characteristic feature of the early phase of the response of mammalian cells to metabolic stresses such as hypoxia, osmotic stress, heat shock or exposure to metabolic poisons is a rapid increase in the rate of glucose uptake. This response is adaptive in that it allows the cell to maintain or regain its ATP levels. Interestingly, the mechanism of the response is cell-type specific: for example in Clone 9 cells transport is increased through activation of glucose transporters (GLUT1) which are already present at the cell surface, whereas in BHK cells stress stimuli induce translocation of GLUT1 to the cell surface from an intracellular compartment. The results of recent studies on the signal transduction events involved in the stress response will be presented, with particular emphasis on the possible roles of phosphatidylinositol 3-kinase and the MAP kinase homologues JNK/SAPK and p38.