• "Structure of the insulin receptor, a heterotetramer consisting of two extracellular insulin-binding subunits linked by a disulfide bonds to tow transmembrane beta subunits. The beta subunits contain an intrinsic tyrosine kinase activity that is activated upon insulin binding to the alpha subunit. "
  • courtesy of Robert H. Parsons, Ph.D., Rensselaer Polytechnic Institute, used with permission