MITOGEN-ACTIVATED PROTEIN-KINASE (MAP KINASE), MAP KINASE KINASE AND C-MOS STIMULATE GLUCOSE-TRANSPORT IN XENOPUS-OOCYTES

Mitogens and growth factors acutely stimulate glucose transport in all cells to supply energy for their growth and division. but little is k nown about the signalling mechanism by which these agonists promote su gar uptake. Here we show that the transport of deoxyglucose and 3-O-me thylglucose into Xenopus laevis oocytes is stimulated about 2.5-fold w hen mitogen-activated protein kinase (MAP kinase) is microinjected int o these oocytes. We also demonstrate that microinjection of the proto- oncogene product c-Mos (an activator of MAP kinase kinase, which activ ates MAP kinase in Xenopus oocytes), and purified MAP kinase kinase pr oduce similar increases in deoxyglucose transport. Since the activatio n of MAP kinase is a general response to almost all mitogens and growt h factors, we propose that one of its downstream effects is the stimul ation of glucose-transport activity.