Robert Townley

I am interested in the molecular and cellular mechanisms of nutrient sensing and
nutrient utilization. These mechanisms are fundamental properties of all living
systems and are important for determining growth, morphogenesis, aging, and behavior
as well as pathological processes such as cancer, diabetes and obesity. My specific
aim, along with Dr. Troy Burke, is to determine a high-resolution structure of the
AMP activated protein kinase, (AMPK).

The AMPK is part of a biochemical network, which senses the onset of ATP
depletion. This network adapts power output to nutrient availability by activating fuel
oxidation reactions and inhibiting biosynthetic reactions like sterol production, and
protein synthesis. The holoenzymes is comprised of three subunits. The a catalytic
subunit is responsible for phosphorylating the substrate. The b subunit effects activation
in vitro and in vivo, localization and substrate interactions. In addition the b subunit
interacts with glycogen. The g subunit is responsible for inhibition of kinase activity by
ATP as well as activation by AMP. It is a member of a growing super-family of proteins
that bind Adenosyl moieties. The goal of my research is to determine in atomic detail
the mechanism of inhibition and activation.

E-mail: rt171@columbia.edu