kinaselike

Kinase-like, sometimes written kinaselike, is a descriptive term used in molecular biology to denote proteins or protein domains that resemble protein kinases in sequence or structure but do not perform canonical phosphotransfer reactions. Kinase-like domains may be found as standalone modules or as parts of larger proteins. In many cases they function not as enzymes but as regulators of signaling, acting as scaffolds, allosteric regulators, or readers of phosphate states.

Most active protein kinases share conserved catalytic motifs within the kinase domain, including a lysine in subdomain II required for ATP binding, an HRD motif in the catalytic loop, and a DFG motif coordinating magnesium and substrate positioning. Kinase-like proteins often harbor substitutions or deletions in these regions, which diminishes or abolishes catalytic activity while preserving the overall fold. As a result, they are related to, but distinct from, classical kinases and from true pseudokinases, though terms are sometimes used interchangeably. Some kinase-like proteins retain residual or substrate-specific activity, while others act purely as non-catalytic regulators.

Functional roles attributed to kinase-like proteins include modulating the activity of nearby kinases, participating in signaling networks as molecular switches, guiding subcellular localization, and forming multiprotein complexes. They are studied via comparative genomics, structural biology, and biochemical assays that test phosphorylation, ATP binding, and substrate interactions.

In research and medicine, kinase-like domains are of interest as potential drug targets or biomarkers, especially when they influence signaling pathways implicated in development, cancer, or metabolic regulation. The term’s usage is not fully standardized, and authors may prefer "kinase-like," "kinaselike," or "pseudokinase" depending on context.