kinase-linked receptor

A kinase-linked receptor turns a signal at the cell surface into a chemical tag inside the cell. A kinase is an enzyme that attaches phosphate groups to proteins, and these phosphate tags act like sticky notes that recruit other proteins and switch pathways on. When the receptor's ligand binds, this tagging machinery springs to life.

Most of these receptors span the membrane just once. Binding of a ligand — typically a growth factor, cytokine or insulin — causes two receptor molecules to pair up, so their intracellular tails come close enough to phosphorylate each other and then phosphorylate downstream signalling proteins. Some receptors carry the kinase activity within their own structure (receptor tyrosine kinases), while others recruit a separate kinase such as a JAK enzyme.

Because these pathways control cell growth, survival and metabolism, they are central targets in cancer and inflammation. The therapeutic caveat is that the same growth-promoting circuitry exists in healthy tissues, so drugs blocking these receptors or their kinases often cause on-target side effects such as skin rash, diarrhoea or impaired wound healing.