reseptortyrosinkinase

Resepetortyrosinkinase is a term used to describe receptor tyrosine kinases (RTKs), a large family of cell-surface receptors that regulate many fundamental cellular processes by phosphorylating tyrosine residues on themselves and on downstream signaling proteins. RTKs respond to extracellular cues such as growth factors, cytokines, and hormones, translating external signals into intracellular responses that control growth, differentiation, metabolism, and survival.

Structurally, most RTKs are single-pass transmembrane proteins with an extracellular ligand-binding domain, a single transmembrane helix, and an intracellular tyrosine kinase domain. Upon ligand binding, RTKs typically dimerize, either as homodimers or heterodimers, and undergo autophosphorylation. The phosphotyrosines in the cytoplasmic tail serve as docking sites for adaptor and effector proteins, initiating downstream signaling cascades.

Common signaling pathways activated by RTKs include the RAS–MAPK pathway, the PI3K–AKT/mTOR pathway, PLCγ–calcium signaling, and, in some contexts, JAK–STAT. Through these pathways RTKs regulate cell cycle progression, differentiation, survival, migration, and metabolism. RTKs are essential for normal development and tissue homeostasis, and their activity is tightly regulated.

Dysregulation of RTKs is associated with numerous diseases, notably cancer, where mutations, gene amplification, overexpression, autocrine ligand production, or chromosomal rearrangements can drive oncogenesis. Because of their central role in signaling, RTKs are important therapeutic targets. Treatments include monoclonal antibodies that block ligand binding or receptor activation and small-molecule tyrosine kinase inhibitors that block kinase activity. Examples span the EGFR, VEGFR, FGFR, and ALK families.