Double feature at the signalplex

In this issue of Molecular Pharmacology, Oliveras-Reyes et al. (p. 356) describe the agonist-stimulated formation of a caveolin-dependent signalplex that includes both the angiotensin AT₁ receptor and the epidermal growth factor receptor, and probably also a number of other signal transduction intermediates. The signalplex is thought to facilitate the action of protein kinases that mediate angiotensin II-induced transactivation of the epidermal growth factor receptor and activation of extracellular signal-regulated kinase, and epidermal growth factor-induced inositol phosphate accumulation and phosphorylation/desensitization of the AT₁ receptor. This work contributes to an emerging view of the complexity and nonlinearity of signaling via G protein-coupled receptors and receptor tyrosine kinases, and of the importance of membrane compartmentalization to signal transduction.