Acts as a positive regulator of ERK phosphorylation downstream of fibroblast growth factor-receptor activation. Involved in the regulation of both caspase-dependent apoptosis and caspase-independent cell death. In the skin, it plays a predominant role in suppressing caspase-dependent apoptosis in response to UV stress in a range of dermal cell types. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Detected in basolateral and apical membranes of all tubular epithelia. Detected at apical cell-cell junctions. Colocalized with FGF receptors to the cell membrane. Expressed in many regions of the adult brain. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.