The cloning of the insulin receptor not only established the primary s
tructure of this membrane-bound glycoprotein but also offered the mate
rial necessary for the study of the molecular functions of this tyrosi
ne-kinase receptor using molecular biology tools. This short review wi
ll summarize the actual knowledge of the structure, the functions (mol
ecular structure of the binding site, tyrosine-kinazse functions and r
ole of autophosphorylation) and of the pathology of this receptor in e
xtreme insulin resistances and type II diabetes.