Michael L. Jennings
Professor and Chair
Ph.D., Harvard University
Office: (501) 296-1438
Lab: (501) 296-1439
My research is focused on the structure, function, and regulation of ion transport proteins. For many years we used the red blood cell chloride-bicarbonate exchange protein known as AE1 as a model system for studying coupled ion transport. Recently our interest shifted to a protein known as BTR1 that is related to AE1. Mutations in BTR1 cause a human condition called CHED (congenital hereditary endothelial dystrophy) of the cornea, which results in cloudy vision. BTR1 has been reported to be a boron transporter, but we have found no evidence that it transports boron. Instead it acts as a pH-regulated channel for H+/OH–. This project is a collaboration with Mark D. Parker of the University of Buffalo.
Another current interest is in hydrogen sulfide (H2S) and sulfide ion (HS–) transport. Although there is considerable evidence for the importance of H2S as a signaling molecule, until recently there were no measurements of H2S or HS– transport through a mammalian cell membrane. I measured the rates of dissipation of pH gradients across the human red blood cell membrane and found that these rates are strongly accelerated by low concentrations of H2S/HS–. With the help of some mathematical modeling, the pH transients were used to quantify the permeability of both H2S and HS–. Sulfide ion is transported rapidly by the Cl– transporter AE1 (about 1/3 as rapidly as Cl–), and H2S penetrates the membrane rapidly by either diffusing through the bilayer or through an aquaporin. These measurements represent the first estimates of the permeation rates of H2S or HS– across a mammalian cell membrane.
A new project is a collaboration with Haibo Zhao of the UAMS Department of Internal Medicine on a project designed to determine the role of Fe3+ transport in osteoclast differentiation and function.
Myers, E.J., Marshall, A., Jennings, M.L., Parker, Mark D. 2016. Mouse Slc4a11 expressed in Xenopus oocytes is an ideally selective H+/OH– conductance pathway that is stimulated by rises in intracellular and extracellular pH. Am. J. Physiol. Cell Physiol. 311: C945-C959.
Jennings, M.L. 2013. Transport of hydrogen sulfide and hydrosulfide anion across the human red blood cell membrane. Rapid H2S diffusion and AE1-mediated Cl–/HS– exchange. Am. J. Physiol. Cell Physiol. 305: C941-C950.
Jennings, M.L., Cui, J. 2012. Inactivation of Saccharomyces cerevisiae sulfate transporter Sul2p: Use it and lose it. Biophysical Journal 102: 768-776.
Jennings, M.L., Cui, J. 2008. Chloride homeostasis in Saccharomyces cerevisiae: High affinity influx, V-ATPase-dependent sequestration, and identification of a candidate Cl– sensor. J. Gen. Physiol. 131: 379-391.
Chernova, M.N., Stewart, A.K., Barry, P.N., Jennings, M.L., Alper S.L. 2008. Mouse AE1 mutant E699Q mediates SO42-i/aniono exchange with reversed pHo sensitivity modulated by [SO42-]o. Am. J. Physiology. Cell Physiol. 295: C302-C312.
Jennings, M.L., Howren T.R., Cui, J., Winters, M., Hannigan, R. 2007. Transport and regulatory characteristics of the yeast bicarbonate transporter homolog Bor1p. Am. J. Physiol. Cell Physiol. 293: C468-C476.