Insulin receptor,molecular model. The insulin receptor is a transmembrane protein,that is it spans the cellular membrane. The part of the receptor that sits on the outside of the cell,the ectodomain,is seen here,complexed with the antigen-binding fragment (Fab) of an antibody. Binding of insulin to the extracellular part of the protein activates a number of changes inside the cell that lead to the uptake of glucose,the synthesis of glycogen and fatty acids and glycolysis,the production of energy from glucose |