Receptor tyrosine kinase family

Like the G protein-coupled receptors (GPCRs,
see p. 268) and their effectors, the receptor tyrosine
kinases (RTKs) are a major class of cell
surface receptors. Their ligands are soluble or
membrane-bound growth factor proteins. RTK
signaling pathways involve a wide variety of
other functions. Mutations in RTKs may send a
proliferative signal even in the absence of a
growth factor, resulting in errors in embryonic
development and differentation (congenital
malformation) or cancer.