The phosphorylation and dephosphorylation of proteins on serine and threonine residues is an essential means of regulating a broad range of cellular functions in eukaryotes, including cell division, homeostasis and apoptosis. A group of proteins that are intimately involved in this process are the serine/threonine (Ser/Thr) protein kinases. LOK (Lymphocyte-oriented kinase), also known as STK10 (serine/threonine kinase 10), is a 968 amino acid protein that contains one protein kinase domain and belongs to the Ser/Thr protein kinase family. Expressed in lymphoid organs, LOK functions to catalyze the ATP-dependent phosphorylation of target proteins, such as MBP (myelin basic protein) and Histone H2A, thereby playing a role in signaling pathways throughout the cell.
