 |
|
 |
Membrane channels and transporters in kidney.
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.
Figure caption:
Confocal microscopy phase contrast image
of a single proximal tubule cell isolated from Ambystoma kidney. The
cell maintains its epithelial polarity, with a prominent brush-border
visible along the apical membrane. Isolated cells are used for patch-clamp
studies of ion channels and for monitoring intracellular free Ca++
concentration by means of fluorescent indicators.
Recent publications:
Choi
I, Aalkjaer C, Boulpaep EL, Boron WF. An
electroneutral sodium/bicarbonate cotransporter NBCn1 and associated
sodium channel. Nature. 2000 Jun 1;405(6786):571-5.
Haitham T. Idriss, Yusuf A. Hannun, Emile Boulpaep and Srisaila Basavappa.
Regulation
of volume-activated chloride channels by P-glycoprotein: phosphorylation
has the final say? J.Physiol. 2000, 524:629-636.
Schmitt BM, Biemesderfer D, Romero MF, Boulpaep EL, Boron WF. Immunolocalization
of the electrogenic Na+-HCO-3 cotransporter in mammalian and amphibian
kidney. Am J Physiol. 1999 Jan;276(1 Pt 2):F27-38.
emile.boulpaep@yale.edu
|
|