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Mechanosensitive channel activity and F‐actin organization in cholesterol‐depleted human leukaemia cells
Author(s) -
Morachevskaya Elena,
Sudarikova Anastasiya,
Negulyaev Yuri
Publication year - 2007
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2007.01.024
Subject(s) - mechanosensitive channels , microbiology and biotechnology , biophysics , lipid bilayer , actin , ion channel , chemistry , cytoskeleton , actin cytoskeleton , patch clamp , lipid raft , cholesterol , biology , biochemistry , membrane , cell , receptor
This study focuses on the functional role of cellular cholesterol in the regulation of mechanosensitive cation channels activated by stretch in human leukaemia K562 cells. The patch‐clamp method was employed to examine the effect of methyl‐β‐cyclodextrin (MβCD), a synthetic cholesterol‐sequestering agent, on stretch‐activated single currents. We found that cholesterol‐depleting treatment with MβCD resulted in a suppression of the activity of mechanosensitive channels without a change in the unitary conductance. The probability that the channel was open significantly decreased after treatment with MβCD. Fluorescent microscopy revealed F‐actin reorganization, possibly involving actin assembly, after incubation of the cells with MβCD. We suggest that suppression of mechanosensitive channel activation in cholesterol‐depleted leukaemia cells is due to F‐actin rearrangement, presumably induced by lipid raft destruction. Our observations are consistent with the notion that stretch‐activated cation channels in eukaryotic cells are regulated by the membrane—cytoskeleton complex rather than by tension developed purely in the lipid bilayer.