Insulin receptor tyrosine kinase structure and function.

Six years have now elapsed since efforts to establish heterologous cell expression systems for studies of the human insulin receptor were begun. As is apparent from the results summarized in Figs. 1 and 2, a significant number of studies have been devoted to the analysis of receptor mutations, both experimentally derived (i.e. by mutagenesis) and those identified in human patients, as well as to the generation of soluble derivatives of the major functional domains of the receptor for use in biophysical studies. While it is certainly clear that these methods can be expected to yield an ever-increasing body of data concerning insulin receptor structure/function, it is equally apparent that attention to a number of basic experimental limitations inherent in these approaches will be required to resolve a number of fundamental questions and disagreements concerning particular receptor mutations. Given the level of interest in the insulin receptor that has persisted over the past several decades, one expects that these efforts will be forthcoming, and that our understanding of this complex transmembrane receptor will, with time, improve.