 In particular, movement of some parts of the kinase domain gives free access to adenosine triphosphate (ATP) and the substrate to the active site.This triggers a cascade of events through phosphorylation of intracellular proteins that ultimately transmit ("transduce") the extracellular signal to the nucleus, causing changes in gene expression.Many RTKs are involved in oncogenesis, either by gene mutation, or chromosome translocation, or simply by over-expression.