Insulin signaling in the adipocyte.

Mammalian adipose tissue serves a number of functions, including storage of nutrients for periods of fasting and control of organismal metabolism. Critical to these functions is the capacity of the fat cell to respond to insulin with a significant increase in glucose uptake. It is now generally recognized that the major site of action of insulin in this tissue is the mobilization of a pool of latent, intracellular transport proteins. Nonetheless, the precise signaling pathways which mediate the insulin-stimulated increase in glucose transport remain uncertain. In recent years, the serine/threonine protein kinase Akt/PKB has emerged as an important candidate signaling molecule. Considerable current effort is being directed at trying to definitively establish whether Akt/PKB is an important intermediate in insulin signaling to glucose transport in muscle and fat.