1. Interaction with stomatin directs human proton channels into cholesterol-dependent membrane domains.
- Author
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Ayuyan AG, Cherny VV, Chaves G, Musset B, Cohen FS, and DeCoursey TE
- Abstract
Many membrane proteins are modulated by cholesterol. Here we report profound effects of cholesterol depletion and restoration on the human voltage-gated proton channel, hH
V 1, in excised patches but negligible effects in the whole-cell configuration. Despite the presence of a putative cholesterol-binding site, a CARC motif in hHV 1, mutation of this motif did not affect cholesterol effects. The murine HV 1 lacks a CARC sequence but displays similar cholesterol effects. These results argue against a direct effect of cholesterol on the HV 1 protein. However, the data are fully explainable if HV 1 preferentially associates with cholesterol-dependent lipid domains, or "rafts." The rafts would be expected to concentrate in the membrane/glass interface and to be depleted from the electrically accessible patch membrane. This idea is supported by evidence that HV 1 channels can diffuse between seal and patch membranes when suction is applied. Simultaneous truncation of the large intracellular N and C termini of hHV 1 greatly attenuated the cholesterol effect, but C truncation alone did not; this suggests that the N terminus is the region of attachment to lipid domains. Searching for abundant raft-associated proteins led to stomatin. Co-immunoprecipitation experiment results were consistent with hHV 1 binding to stomatin. The stomatin-mediated association of HV 1 with cholesterol-dependent lipid domains provides a mechanism for cells to direct HV 1 to subcellular locations where it is needed, such as the phagosome in leukocytes., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Biophysical Society. Published by Elsevier Inc. All rights reserved.)- Published
- 2024
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