The most detailed 3-D picture yet has been created of a membrane protein linked to learning, memory, anxiety, pain and brain disorders such as schizophrenia, Parkinson’s, Alzheimer’s and autism. The mGlu1 receptor, which helps regulate the neurotransmitter glutamate, belongs to a superfamily of molecules known as G protein-coupled receptors (GPCRs). GPCRs sit in the cell membrane and sense various molecules outside the cell, including odors, hormones, neurotransmitters and light. After binding these molecules, GPCRs trigger a specific response inside the cell. More than one-third of therapeutic drugs target GPCRs -— including allergy and heart medications, drugs that target the central nervous system and anti-depressants.