My lab is studying regulation of the Na/K pump in heart. This enzyme uses the energy stored in ATP to transport 3 Na+ out of the cell and 2 K+ into the cell during each cycle. Thus the pump generates a net outward current, which we directly measure using the whole cell patch clamp technique. There are at least 3 isoforms of the Na/K pump and each is specifically expressed in different regions of the heart. We have shown that each isoform has a unique set of responses to the physical environment (e.g. ion concentration, voltage) and is uniquely coupled to autonomic nervous input. We are currently investigating the molecular mechanisms responsible for the various functional responses. Moreover, we are studying role of regulation of each isoform on the cardiac action potential, pacemaking and force generation.
Mathias, R.T., Cohen, I.S.,
Gao, J., and Wang, Y. (2000) Isoform specific regulation of the Na/K
pump in heart. News in Physiological Sciences. In press.