Aminoglycoside 3'-phosphotransferase and Choline Kinase family
This family is composed of APH, ChoK, ethanolamine kinase (ETNK), macrolide 2'-phosphotransferase (MPH2'), an unusual homoserine kinase, and uncharacterized proteins with similarity to the N-terminal domain of acyl-CoA dehydrogenase 10 (ACAD10). The members of this family catalyze the transfer of the gamma-phosphoryl group from ATP (or CTP) to small molecule substrates such as aminoglycosides, macrolides, choline, ethanolamine, and homoserine. Phosphorylation of the antibiotics, aminoglycosides and macrolides, leads to their inactivation and to bacterial antibiotic resistance. Phosphorylation of choline, ethanolamine, and homoserine serves as precursors to the synthesis of important biological compounds, such as the major phospholipids, phosphatidylcholine and phosphatidylethanolamine and the amino acids, threonine, methionine, and isoleucine. The APH/ChoK family is part of a larger superfamily that includes the catalytic domains of other kinases, such as the typical serine/threonine/tyrosine protein kinases (PKs), RIO kinases, actin-fragmin kinase (AFK), and phosphoinositide 3-kinase (PI3K).