Ricerc@Sapienza

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.

Exosomes, small vescicles with a lipid bilayer, are released from many cell types and are part of the cell secretrome that can play a role in intercellular communication. They originate from cytoplasmic multivescicular bodies, fuse with the plasma membrane and release their content of lipids, proteins and RNAs in the extracellular space or in target cells. A growing body of evidence suggests that exosomes contribute to many aspects of healthy and pathological cells, and they may influence the homeostasis of target cells.