Regulation of magnesium-inhibited cation current by actin cytoskeleton rearrangement

Magnesium-inhibited, non-selective cation current (IMIC) is activated by depletion of intracellular Mg2+ and ATP. IMIC transports various divalent cations including Mg2+ and Ca2+, and is involved in cell viability. We investigated the effect of actin dynamics on IMIC. Formation of a stable cortical actin network by calyculin A inhibited the activation of IMIC, while the actin depolymerizing reagent, cytochalasin D, reversed the inhibition. Induction of a dense cortical actin layer by transfecting the constitutively active form of RhoA also inhibited the activation of IMIC. These results suggest that the activation of IMIC may be dynamically regulated by actin cytoskeleton rearrangement.