Developmental roles for Homer: more than just a pretty scaffold

Homer proteins are best known as scaffold proteins at the post-synaptic density where they facilitate synaptic signalling and are thought to be required for learning and memory. Evidence implicating Homer proteins in the development of the nervous system is also steadily accumulating. Homer is highly conserved and is expressed at key developmental time points in the nervous system of several species. Homer regulates intracellular calcium homeostasis, clustering and trafficking of receptors and proteins at the cytosolic surface of the plasma membrane, transcription and translation, and cytoskeletal organization. Each of these functions has obvious potential to regulate neuronal development, and indeed Homer is implicated in several pathologies associated with the developing nervous system. Current data justify more critical experimental approaches to the role of Homer in the developing nervous system and related neurological disorders. Keywords: Homer, mental retardation, mGluR, neuronal development, synaptic signalling. J. Neurochem. (2009) 108, 1–10.