Identification of a specialized adenylyl cyclase that may mediate odorant detection.
The mammalian olfactory system may transduce odorant information via a G protein-mediated adenosine 3',5'-monophosphate (cAMP) cascade. A newly discovered adenylyl cyclase, termed type III, has been cloned, and its expression was localized to olfactory neurons. The type III protein resides in the sensory neuronal cilia, which project into the nasal lumen and are accessible to airborne odorants. The enzymatic activity of the type III adenylyl cyclase appears to differ from nonsensory cyclases. The large difference seen between basal and stimulated activity for the type III enzyme could allow considerable modulation of the intracellular cAMP concentration. This property may represent one mechanism of achieving sensitivity in odorant perception.
Bakalyar
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HA
Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Reed
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RR
D000262:Adenylyl Cyclases / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology / Q000502:physiology; D002460:Cell Line; D002999:Clone Cells; D003001:Cloning, Molecular; D015723:Gene Library; D006031:Glycosylation; D007527:Isoenzymes / Q000235:genetics / Q000502:physiology*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009475:Neurons, Afferent / Q000201:enzymology / Q000502:physiology; D009666:Nose / Q000201:enzymology / Q000502:physiology; D009812:Odorants; D011487:Protein Conformation; D051381:Rats; D015398:Signal Transduction
D007527:Isoenzymes; D046911:Macromolecular Substances; D000262:Adenylyl Cyclases