Kinasecontaining

Kinase-containing refers to proteins that possess a kinase domain capable of catalyzing the transfer of a phosphate group to substrates, typically on serine, threonine, or tyrosine residues, often using ATP as the phosphate donor. These proteins are central to a wide range of signaling pathways that regulate cell growth, differentiation, metabolism, and apoptosis.

Most kinase-containing proteins fall into two broad structural classes: receptor-type kinases, which span the plasma membrane and have an extracellular ligand-binding region, a single transmembrane helix, and an intracellular kinase domain; and cytoplasmic or non-receptor kinases, which function within the cytosol or nucleus. Many kinases are modular, combining catalytic domains with regulatory motifs (such as SH2, SH3, PH, or PDZ domains) that control activity and localization.

Classification typically distinguishes serine/threonine kinases, tyrosine kinases, and dual-specificity kinases. A subset known as pseudokinases resembles kinases but lacks catalytic activity, yet can regulate signaling by scaffolding or allosteric effects.

Functionally, phosphorylation by kinase-containing proteins modulates enzyme activity, protein interactions, stability, and cellular localization, thereby propagating and regulating signaling networks. Dysregulation of kinase signaling is linked to numerous diseases, particularly cancer, diabetes, and inflammatory disorders. Kinases are major therapeutic targets, with inhibitors used clinically to treat various conditions.

Examples of well-known kinase-containing proteins include MAP kinases (such as ERK1/2), cyclin-dependent kinases (CDKs), protein kinase B (AKT), Src-family kinases, JAKs, and epidermal growth factor receptor (EGFR). In humans, the kinome comprises roughly 500 protein kinases, reflecting the diverse roles of kinase-containing proteins across biology.