Background: M-channels are potassium channels that are activated by phosphatidylinositol 4,5-bisphosphate, but their response to other phospholipids is unknown.Results: M-channel proteins were activated by phosphoinositides and lipid phosphates but not by inositol phosphates.Conclusion: Minimum activation requirements are an acyl chain and one or more phosphate groups.Significance: M-channels control cell excitability, so their regulation by membrane constituents is important for biology.

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Skin keratinocytes fulfil important signalling and protective functions. Immunocytochemical experiments revealed the unexpected presence of immunoreactivity for the M-type potassium channel subunit Kv7.2 in the keratinocyte layer of intact rat paw skin and in keratinocytes isolated from the skin of 1-day-old rats and cultured in vitro for 3–10 days. Application of the M-channel enhancer retigabine (3–10 μM) to isolated cultured rat keratinocytes: (a) increased outward membrane currents recorded under voltage clamp, (b) produced ~3 mV hyperpolarization at rest, (c) enhanced ~3-fold the release of ATP induced by the TRPV3 agonist carvacrol (1 mM) and (d) increased the amplitude of the carvacrol-induced intracellular Ca2+ transient measured with Fura-2. The effect of retigabine on ATP release was prevented by the M-channel blocking agent XE991. We conclude that rat skin keratinocytes possess M-channels that, when activated, can modify their physiological properties, with potential significance for their sensory and other biological functions.Electronic supplementary materialThe online version of this article (doi:10.1007/s00424-013-1276-2) contains supplementary material, which is available to authorized users.