TRPM7 knockdown experiments were performed as described previously [22 (link);23 (link)]. Briefly, special siRNA targeting nucleotides 406–426 of human TRPM7 (NM_017672) was synthesized from Invitrogen. Cells were treated with 30 nM siRNA using transfection reagent lipofectamineTM RNAiMAX (Invitrogen) according to the manufacturer’s instructions. Non-targeting siRNA (Invitrogen) was used as a negative control