Molecular mechanisms of taste transduction*
Robert F. Margolskee
Howard Hughes Medical Institute, Department of Physiology
and Biophysics, 1425 Madison Avenue, Box 1677, Mount Sinai School of
Medicine, New York, NY 10029, USA
Abstract: Taste transduction is a specialized form
of signal transduction by which taste receptor cells (TRCs) encode at
the cellular level information about chemical substances encountered
in the oral environment (so-called tastants). Bitter and sweet taste
transduction pathways convert chemical information into a cellular second
messenger code utilizing cyclic nucleotides, inositol trisphosphate,
and/or diacyl glycerol. These messengers are components of signaling
cascades that lead to TRC depolarization and Ca++ release. Bitter and
sweet taste transduction pathways typically utilize taste-specific or
taste-selective seven transmembrane-helix receptors, G proteins, effector
enzymes, second messengers, and ion channels. The structural and chemical
diversity of tastants has led to the need for multiple transduction
mechanisms. Through molecular cloning and data mining, many of the receptors,
G proteins, and effector enzymes involved in transducing responses to
bitter and sweet compounds are now known. New insights into taste transduction
and taste coding underlying sweet and bitter taste qualities have been
gained from molecular cloning of the transduction elements, biochemical
elucidation of the transduction pathways, electrophysiological analysis
of the function of taste cell ion channels, and behavioral analysis
of transgenic and knockout models.
* A special topic issue on the
science of sweeteners.
E-mail: [email protected]**
Corresponding author.
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