The AMP-activated protein kinase (AMPK) has been referred to as an "energy sensor" because it binds to and is regulated by both AMP and ATP. The binding of AMP to AMPK allows it to be phosphorylated by upstream kinases, resulting in its activation. In contrast, the binding of ATP prevents its activation. AMPK regulates a multitude of metabolic processes that cumulatively function to maintain cellular energy homeostasis through repression of a number of energy-consuming processes with simultaneous enhancement of energy-producing processes. One downstream AMPK target that has been recently identified is the mammalian target of rapamycin (mTOR), a positive effector of cell growth and division. The focus of the present review is to briefly summarize current knowledge concerning the regulation of mTOR signaling by AMPK.
Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA
Address for correspondence: Scot R. Kimball, Ph.D., Department of Cellular and Molecular Physiology, H166, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033; E-mail: firstname.lastname@example.org.
Submitted for publication December 2005.
Accepted for publication February 2006.