Five years have passed since the first cloning and sequencing of a large family of G protein-coupled receptors from the olfactory epithelium. These receptors are believed to be the initial sites of odor transduction. Although direct experimental evidence concerning the properties of these molecules is still limited, a variety of studies has provided fascinating insights into a range of possible functions, extending beyond olfactory transduction to include functions as diverse as sperm navigation and neural and cardiac development. To serve these functions, the olfactory receptors appear to express interesting adaptations of the basic seven transmembrane domain structures found in the neurotransmitter members of the G protein-coupled receptor superfamily. We review here this evidence and propose hypotheses for the molecular mechanisms underlying several distinct functions for this receptor family as guides for future experimental testing. NEUROSCIENTIST 2:262-271, 1996
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