Calcium-activated non selective (CAN) cation channel that mediates membrane depolarization. While it is activated by increase in intracellular Ca(2+), it is impermeable to it (PubMed:17188667, PubMed:29211714). Mediates transport of monovalent cations (Na(+) > K(+) > Cs(+) > Li(+)), leading to depolarize the membrane. It thereby plays a central role in cadiomyocytes, neurons from entorhinal cortex, dorsal root and vomeronasal neurons, endocrine pancreas cells, kidney epithelial cells, cochlea hair cells etc. Participates in T-cell activation by modulating Ca(2+) oscillations after T lymphocyte activation, which is required for NFAT-dependent IL2 production. Involved in myogenic constriction of cerebral arteries. Controls insulin secretion in pancreatic beta-cells. May also be involved in pacemaking or could cause irregular electrical activity under conditions of Ca(2+) overload. Affects T-helper 1 (Th1) and T-helper 2 (Th2) cell motility and cytokine production through differential regulation of calcium signaling and NFATC1 localization. Enhances cell proliferation through up-regulation of the beta-catenin signaling pathway (By similarity). Essential for the migration but not the maturation of dendritic cells (PubMed:18758465). Plays a role in keratinocyte differentiation (By similarity). Gating is voltage-dependent and repressed by decavanadate. Calmodulin-binding confers the Ca(2+) sensitivity. ATP is able to restore Ca(2+) sensitivity after desensitization. Phosphatidylinositol 4,5-bisphosphate (PIP2)-binding strongly enhances activity, by increasing the channel's Ca(2+) sensitivity and shifting its voltage dependence of activation towards negative potentials. Activity is also enhanced by 3,5-bis(trifluoromethyl)pyrazole derivative (BTP2) (By similarity). Inhibited by flufenamic acid and glibenclamide (PubMed:17188667). Homotetramer. Sino-atrial nodes (at protein level). Widely expressed. Phosphorylation by PKC leads to increase the sensitivity to Ca(2+). Sumoylated. Desumoylated by SENP1. Mice have fewer dendritic cells in lymphoid organs and impaired migration of dendritic cells is seen. Belongs to the transient receptor (TC 1.A.4) family. LTrpC subfamily. TRPM4 sub-subfamily.