Cells don't operate in isolation. They constantly receive and respond to signals from their surroundings.This communication is often mediated by receptors - proteins on the cell surface that bind to specific molecules, triggering a cascade of events inside the cell.Among these receptors, G protein-coupled receptors (GPCRs) stand out as a especially crucial and versatile family.
GPCRs are characterized by their structure: seven transmembrane domains (segments that span the cell membrane) and a binding site for a G protein. When a signaling molecule, like a hormone or neurotransmitter, binds to the GPCR, it activates the associated G protein. This activation initiates a signaling pathway, ultimately leading to a cellular response.