Ricerc@Sapienza

Amyotrophic lateral sclerosis (ALS) is a complex genetic, late age-onset, progressive neurodegenerative disorder leading to the death of upper and lower motor neurons. Life expectancy after diagnosis is short due to the ongoing degeneration and to the lack of effective treatments. Axonal alterations, mitochondrial deficits, RNA changes, protein misfolding and turnover, glial dysfunction and hyperexcitability are key players in molecular mechanisms involved in the degeneration of motor neurons.

In astrocytes, the intracellular calcium (Ca2+) signaling mediated by activation of metabotropic glutamate receptor 5 (mGlu5) is crucially involved in the modulation of many aspects of brain physiology, including gliotransmission. Here, we find that the mGlu5-mediated Ca2+ signaling leading to release of glutamate is governed by mGlu5 interaction with Homer1 scaffolding proteins. We show that the long splice variants Homer1b/c are expressed in astrocytic processes, where they cluster with mGlu5 at sites displaying intense local Ca2+ activity.