Regulation of receptor tyrosine kinase hetero-interactions

Abstract

Receptor tyrosine kinases (RTKs) control myriads of cellular functions. RTKs are paradigmatic examples of receptors where activity is directly dependent on quaternary structure. In most cases, the monomeric RTK is inactive, and function arises only after a ligand binding event leads the RTK to bind to another copy of itself, activating trans-autophosphorylation of tyrosine residues. Such RTK homodimerization can be accompanied by the formation of homomers of higher stoichiometry. However, RTK monomers can also bind to a second type of RTK, forming heterodimers. RTK heteromerization is believed to result in different signaling than homomerization. Despite its importance, we have a poor understanding of the factors that define if an RTK will form homomers or heteromers. This short review covers recent discoveries on the heteromerization of RTK, in what is called the RTK interactome. We discuss its translational potential, and how ligands and membrane lipids affect heteromer formation.