Referenced in: none

Automatically associated channels: Kir2.1

Title: Use of microphysiometry for analysis of heterologous ion channels expressed in yeast.

Authors: K M Hahnenberger, M Krystal, K Esposito, W Tang, S Kurtz

Journal, date & volume: Nat. Biotechnol., 1996 Jul , 14, 880-3

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/9631015

Abstract
Measurement of extracellular acidification rates by microphysiometry provides a means to analyze the function of ion channels expressed in yeast cells. These measurements depend on the proton pumping action of the H(+)-ATPase, a central component of the yeast plasma membrane. We used microphysiometry to analyze the activity of two ion channels expressed in yeast. In one example, an inwardly rectifying K+ channel, gpIRK1, provides a potassium uptake function when expressed in a potassium transporter-defective yeast strain. Rates of acidification in gpIRK1-expressing cells directly reflect channel function. Addition of cesium, an inhibitor of gpIRK1 activity, results in an immediate reduction in acidification rates. In a second example, expression of a nonselective cation channel, the influenza virus M2 protein, is believed to interfere with the maintenance of the electrochemical proton gradient by the H(+)-ATPase. In cells expressing the M2 channel, addition of inhibitors increases the rate of proton extrusion. Moreover, functional differences between two M2 inhibitors, amantadine and BL-1743, are distinguished by the microphysiometer. This application demonstrates the utility of the microphysiometer for functional studies of ion channels; it is adaptable to a screening process for compounds that modulate ion channel activity.