|MadSci Network: Cell Biology|
Olfactory receptors are located on modified cilia (projections) extending from the surface of olfactory neurons. Olfactory receptors are members of the G-protein coupled receptor superfamily of proteins. Each olfactory receptor has a domain on the extracellular surface of the neuron which binds to odarants. The receptor possesses seven transmembrane domains which keep the receptor in the neuronal plasma membrane. On the intracellular side of the olfactory neuron the receptor has a domain which can bind to another protein called a G protein. An odorant binds to the receptor and the signal is transferred (transduced) to its intacellular domain and activates the G protein which initiates a cascade of events leading to the generation of a nerve impulse down the axon of the olfactory neuron to the brain. All olfactory receptors have this basic structure and function. They can recognize over 10,000 different smells.
For more information, see Molecular Biology of the Cell, pp752-3, B. Alberts, editor, Garland Publishing Inc, 1994.
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