Pseudokinase domain of STE20-related kinase adapter protein beta
The pseudokinase domain shows similarity to protein kinases but lacks crucial residues for catalytic activity.STRAD-beta is also referred to as ALS2CR2 (Amyotrophic lateral sclerosis 2 chromosomal region candidate gene 2 protein), since the human gene encoding it is located within the juvenile ALS2 critical region on chromosome 2q33-q34. It is not linked to the development of ALS2. STRAD forms a complex with the scaffolding protein MO25, and the serine/threonine kinase (STK), LKB1, resulting in the activation of the kinase. In the complex, LKB1 phosphorylates and activates adenosine monophosphate-activated protein kinases (AMPKs), which regulate cell energy metabolism and cell polarity. LKB1 is a tumor suppressor linked to the rare inherited disease, Peutz-Jeghers syndrome, which is characterized by a predisposition to benign polyps and hyperpigmentation of the buccal mucosa. The STRAD-beta subfamily is part of a larger superfamily that includes the catalytic domains of STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.