Original Publication Date
The Biophysical Journal
DOI of Original Publication
Date of Submission
Kir channels play an important role in setting the resting membrane potential and modulating membrane excitability. A common feature of several Kir channels is that they are regulated by cholesterol. Yet, the mechanism by which cholesterol affects channel function is unclear. We recently showed that the cholesterol sensitivity of Kir2 channels depends on several CD-loop residues. Here we show that this cytosolic loop is part of a regulatory site that also includes residues in the G-loop, the N-terminus, and the connecting segment between the C-terminus and the inner transmembrane helix. Together, these residues form a cytosolic belt that surrounds the pore of the channel close to its interface with the transmembrane domain, and modulate the cholesterol sensitivity of the channel. Furthermore, we show that residues in this cluster are correlated with residues located in the most flexible region of the G-loop, the major cytosolic gate of Kir2.1, implying that the importance of these residues extends beyond their effect on the channel's cholesterol sensitivity. We suggest that the residues of the cholesterol sensitivity belt are critical for channel gating.
From The Biophysical Journal, Rosenhouse-Dantsker, A., Logothetis, D.E., and Levitan, I., Cholesterol Sensitivity of KIR2.1 Is Controlled by a Belt of Residues around the Cytosolic Pore, Vol. 100, Page 381, Copyright © 2011 Biophysical Society. Published by Elsevier Inc. Reprinted with permission.
Is Part Of
VCU Physiology and Biophysics Publications