Modulation of mechanosensitive calcium-selective cation channels by temperature.
Gating of associations of mechanosensitive Ca(2+)-selective cation co-channels in the plasmalemma of onion epidermis has a strong and unusual temperature dependence. Tension-dependent activity rises steeply as temperature is lowered from 25 degrees C to about 6 degrees C, but drops to a low level at about 5 degrees C. Under the conditions tested (with Mg2+ and K+ at the cytosolic face of outside-out membrane patches), promotion results both from more bursting at all observed linkage levels and from longer duration of bursts of co-channels linked as quadruplets and quintuplets. Co-channel conductance decreases linearly, but only modestly, with declining temperature. It is proposed that these and related mechanosensitive channels may participate in a variety of responses to temperature, including thermonasty, thermotropism, hydrotropism, and both cold damage and cold acclimation.
Biology Department, Washington University, Saint Louis, MO 63130-4899.
J P
JP
Ding
B G
BG
Pickard
D000490:Allium / Q000378:metabolism*; D001696:Biomechanical Phenomena; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004594:Electrophysiology; D015640:Ion Channel Gating; D013696:Temperature
D015220:Calcium Channels; D002118:Calcium