Protein kinase domain (PK domain) (PK domain)

The protein kinase domain is a highly conserved structural motif responsible for the catalytic activity of protein kinases, which transfer a phosphate group from ATP to specific substrates such as serine, threonine, or tyrosine residues (Manning et al., 2002, Science). This domain consists of a small N-terminal lobe and a larger C-terminal lobe, with an ATP-binding cleft situated between them (Taylor & Kornev, 2011, Trends in Biochemical Sciences). As central mediators of intracellular signaling, kinases regulate nearly every aspect of cellular life, including growth, differentiation, and metabolism (Roskoski, 2016, Pharmacological Research). Dysregulation of kinase activity, often through mutation or overexpression, is a hallmark of numerous diseases, particularly cancer and inflammatory disorders (Bhullar et al., 2018, Molecular Cancer). Consequently, the protein kinase domain is one of the most important classes of drug targets in modern pharmacology, with hundreds of small-molecule inhibitors designed to bind within the ATP-binding pocket or at allosteric sites to modulate signaling pathways (Ferguson & Gray, 2018, Nature Reviews Drug Discovery). The high degree of structural conservation across the human kinome presents both opportunities for broad-spectrum therapy and challenges regarding off-target toxicity and selectivity.

Other names

PkinaseEukaryotic protein kinase domainCatalytic kinase domainProtein kinase catalytic domain

Inhibition of protein phosphorylation through ATP-competitive binding, allosteric modulation, or covalent modification of the catalytic domain (Roskoski, 2016, Pharmacological Research).