Involvement of calmodulin and myosin light chain kinase in activation of mTRPC5 expressed in HEK cells

Abstract

The classic type of transient receptor potential channel (TRPC) is a molecular candidate for Ca(2+)-permeable cation channels in mammalian cells. Because TRPC channels have calmodulin (CaM) binding sites at their COOH termini, we investigated the effect of CaM on mTRPC5. TRPC5 was initially activated by muscarinic stimulation with 50 microM carbachol and then decayed rapidly even in the presence of carbachol. Intracellular CaM (150 microg/ml) increased the amplitude of mTRPC5 current activated by muscarinic stimulation. CaM antagonists (W-7 and calmidazolium) inhibited mTRPC5 currents when they were applied during the activation of mTRPC5. Pretreatment of W-7 and calmidazolium also inhibited the activation of mTRPC5 current. Inhibitors of myosin light chain kinase (MLCK) inhibited the activation of mTRPC5 currents, whereas inhibitors of CaM-dependent protein kinase II did not. Small interfering RNA against cardiac type MLCK also inhibited the activation of mTRPC5 currents. However, inhibitors of CaM or MLCK did not show any effect on GTPgammaS-induced currents. Application of both Rho kinase inhibitor and MLCK inhibitor inhibited GTPgammaS-induced currents. We conclude that CaM and MLCK modulates the activation process of mTRPC5.

Characteristics of the Cholecystokinin-Induced Depolarization of Pacemaking Activity in Cultured Interstitial Cells of Cajal from Murine Small Intestine

“…9A; a ) from that in the presence of CCK (Fig. 9A; b ) was similar to that of overexpressed TRPC5 (transient receptor potential classical 5) in HEK 293 cells [33,34]. These results suggest that TRPC5 channel is a candidate for CCK induced inward currents in cultured ICCs from murine small intestine.…”

Different Effect of Rho Kinase Inhibition on Calcium Signaling in Rat Isolated Large and Small Arteries

“…Other cytoskeleton components could be involved in the effect of ROCK [31]. It has been suggested in HEK cells that the upper activator of MLC, MLC kinase, modulates the activation process of TRPC5 [32], which reveals a potential interaction between ROCK, MLC kinase, myosin and calcium channels that is worth being investigated in the future. …”

Identification of a Membrane-targeting Domain of the Transient Receptor Potential Canonical (TRPC)4 Channel Unrelated to Its Formation of a Tetrameric Structure

“…The whole cell configuration was used to measure TRPC channel current in HEK cells as described previously (13)(14)(15)(16)(17). Cells were left for 10 -15 min to attach to coverslips.…”