Enzyme-Linked Receptors

Enzyme-linked receptors are a group of multi-subunit transmembrane proteins that contain either intrinsic enzyme activity on their intracellular domain or associate directly with an intracellular enzyme. Upon ligand binding a conformational change is transmitted via a transmembrane helix which activates the enzyme, initiating signaling cascades.


There are five main types of enzyme-linked receptors:

  1. Receptor Tyrosine Kinase (RTK): Contains intrinsic tyrosine kinase activity (EGFR, VEGFR)
  2. Receptor Serine/Threonine Kinase: Contains intrinsic serine/threonine kinase activity (TGF-βR)
  3. Receptor Guanylyl Cyclases: Contain intrinsic cyclase activity (ANP)
  4. Tyrosine-Kinase Associated Receptors: Receptors that associate with proteins that have tyrosine kinase activity (Cytokine Receptors)
  5. Receptor Tyrosine Phosphatases
Physiology and Disease

Enzyme-linked receptors are the receptors for many growth factors, cytokines and hormones and have a major role in regulation of cell growth, proliferation and differentiation. Mutations in receptor tyrosine kinases are responsible for a wide array of diseases, including cancers, neurodegeneration, achondroplasia and atherosclerosis.