Rabbit Anti-Human IR/IGF1R (phospho Tyr1162, Tyr1163) monoclonal antibody for ELISA, WB. Biological actions of insulin and IGF-1 are mediated by their respective cell surface receptor tyrosine kinases that regulate multiple signaling pathways through activation of a series of phosphorylation cascades. The insulin receptor. Insulin/IGF-1 binding to the extracellular domain leads to autophosphorylation of downstream target proteins. These two receptors differ in sequence in regions that confer specificity for the designated ligand as well as in certain intracellular signaling domains, resulting in significant differences in the functional consequences of activation of each receptor. Defects in IR are the cause of various insulin resistance syndromes and IGF-1R defects may cause some forms of growth retardation. Both these signaling cascades are also important for the development of cancer.