Regulation of biological functions by an insulin receptor monoclonal antibody in insulin receptor beta-subunit mutants

Transmembrane signalling in cell lines transfected with and expressing both normal human insulin receptors and receptors mutated in their beta-subunit tyrosine kinase domains was investigated. The effect of MA-5, a human-specific monoclonal antibody to the insulin receptor alpha-subunit, on these cell lines was determined. The results suggest that there may be multiple signal transduction pathways for the biological action of insulin. Moreover, some of these pathways may not require the activation of receptor tyrosine kinase.