Structural features of the receptor tyrosine kinase ectodomains

Abstract

The receptor tyrosine kinases (RTKs) can be classified in twenty classes on the basis of the structural architecture of their extracellular components (or "ectodomains"). RTK ectodomains are modular in structure and comprise domains drawn from fifteen distinct fold topologies. We present here an overview of this rich domain architecture to provide structural biology reference material for the ensuing chapters. In addition, we describe how the structural biology of ligand binding to the RTK ectodomain and the subsequent nature of signal transduction vary across the RTK superfamily - in particular, four distinct modes of receptor activation are discerned. However, much of the molecular detail of this remarkably broad family of receptors remains only partially understood.