Modulation of plant TPC channels by polyunsaturated fatty acids

Poyunsaturated fatty acids (PUFAs) are powerful modulators of several animal ion channels. It is shown here that PUFAs strongly affect the activity of the Slow Valcuolar (SV) channel encoded by the plant TPC1 gene. The patchclamp technique was applied to isolated vaculoes from carrot taproots and Arabidopsis thaliana mesophyll cells and arachidonic acid (AA) was chosen as a model molecule for PUFAs. Our study was extended to different PUFAs inhibited the SV channel decreasing the maximum opne probability and shifting the half activation voltage to positive values. Comparing the effects of different PUFAs, it was found that the length of the lipophilic acyl chain, the number of double bonds and the polar head were critical for channel modulation. The experimental data can be reproduced by a simple three-state model, in which PUFAs do not interact directly with the voltage sensors but affect the vltage independent transition that leads the channel from the open state to the closed configuration. The results indicate that lipids play an important role in co-ordinating ion channel activities similar to what is known from animal cells. © 2012 The Author.