Definition:

Receptor protein tyrosine kinases (RPTK) is a ransmembrane (TM) protein, monitoring a cell s extracellular environment and produce internal cellular responses to external cues. RPTK consists an extracellular ligand binding domain, a hydrophobic TM domain and a cytoplasmic kinase domain. RPTK signal transduction is initiated when a polypeptide ligand binds to the extracellular domain of the receptor. Ligand binding induces receptor oligomerization resulting in autophosphorylation of the cytoplasmic portion of the receptor. Ultimately, interaction of activated RPTK with cytoplasmic proteins leads to changes in metabolism and gene transcription. RPTK play crucial roles in cell-growth regulation, differentiation and development of metazoan organisms.