Emile Boulpaep, MD

Polarized kidney tubule cells have proteins in the plasma membrane facing the urine that differ from those facing the blood. We are studying the electrical characteristics of these proteins-ion channels and electrogenic transporters-in the two plasma membranes of renal tubule cells. Patch-clamp, optical and molecular biology techniques are being used.

1. We study the physiological role and regulation of single small-conductance chloride channels, which are activated by cAMP through phosphorylation by protein kinase A. Our interest is in the intracellular signal transduction pathways involved in the regulation of these renal channels and their homology with the CFTR protein, known to be deficient in cystic fibrosis.
2. We study the physiological role and regulation of a cGMP-sensitive non-selective cation channel in the apical membrane of a kidney cell line and its homology with a cGMP-gated non-selective channel of the vertebrate photoreceptor.
3. Using confocal vital microscopy and ion-sensitive fluorescent dyes, we study a model of proximal tubule cell injury induced by angiotensin II, which is accompanied by elevation of intracellular calcium and plasma membrane blebbing.