The function of TRPM4 (transient receptor potential cation channel subfamily M member 4, Ensembl gene identifier ENSG00000130529) is as follows. Calcium-activated selective cation channel that mediates membrane depolarization (PubMed:12015988, PubMed:12842017, PubMed:29211723, PubMed:30528822). While it is activated by increase in intracellular Ca(2+), it is impermeable to it (PubMed:12015988). Mediates transport of monovalent cations (Na(+) > K(+) > Cs(+) > Li(+)), leading to depolarize the membrane (PubMed:12015988). 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. Plays a role in keratinocyte differentiation (PubMed:30528822). {ECO:0000269|PubMed:11535825, ECO:0000269|PubMed:12015988, ECO:0000269|PubMed:12799367, ECO:0000269|PubMed:12842017, ECO:0000269|PubMed:14758478, ECO:0000269|PubMed:15121803, ECO:0000269|PubMed:15331675, ECO:0000269|PubMed:15472118, ECO:0000269|PubMed:15550671, ECO:0000269|PubMed:15590641, ECO:0000269|PubMed:15845551, ECO:0000269|PubMed:16186107, ECO:0000269|PubMed:16407466, ECO:0000269|PubMed:16424899, ECO:0000269|PubMed:16806463, ECO:0000269|PubMed:20625999, ECO:0000269|PubMed:20656926, ECO:0000269|PubMed:29211723, ECO:0000269|PubMed:30528822}. [Isoform 2]: Lacks channel activity. .