The function of ENSG00000180815 (MAP3K15, mitogen-activated protein kinase kinase kinase 15) is as follows. Serine/threonine kinase which acts as a component of the MAP kinase signal transduction pathway (PubMed:20362554, PubMed:26732173). Once activated, acts as an upstream activator of the p38 MAPK signal transduction cascade through the phosphorylation and activation of several MAP kinase kinases (PubMed:20362554, PubMed:26732173). May function in a signal transduction pathway that is activated by various cell stresses and leads to apoptosis (PubMed:20362554). Involved in phosphorylation of WNK4 in response to osmotic stress or hypotonic low- chloride stimulation via the p38 MAPK signal transduction cascade (PubMed:26732173). {ECO:0000269|PubMed:20362554, ECO:0000269|PubMed:26732173}.