Lab Overview
The vertebrate sensory nervous system enables fine detection of varied external
information. The sense of touch consists of the perception of multiple discrete
types of stimuli, including temperature, pain, position, and pressure. A great
deal remains unknown about the molecular pathways that lead to the diversity
of somatic neurons that sense "touch" and their ability to detect
various stimuli. We are using genomics, imaging, and transgenic technologies
to identify and characterize proteins involved in the development and function
of these sensory neurons.
Highlight
Noxious compounds activate TRPA1 ion channel via covalent modification of
cysteines
Lindsey J. Macpherson (TSRI graduate student), Adrienne E. Dubin, Michael J.
Evans, Felix Marr, Peter G. Schultz, Benjamin F. Cravatt, Ardem Patapoutian
The nervous system senses peripheral damage through nociceptive neurons that
transmit a pain signal. TRPA1 is a member of the Transient Receptor Potential
(TRP) family of ion channels and is expressed in nociceptive neurons. TRPA1
is activated by a variety of noxious stimuli including cold temperatures, pungent
natural compounds, and environmental irritants. How such diverse stimuli activate
TRPA1 is not known. We observed that most compounds known to activate TRPA1
are able to covalently bind cysteine residues. We used click chemistry to show
that derivatives of two such compounds, mustard oil and cinnamaldehyde, indeed
covalently bind the channel. Structurally unrelated cysteine-modifying agents
such as iodoacetamide (IA) and (2-aminoethyl)methanethiosulfonate (MTSEA) also
bind and activate TRPA1. We identified by mass spectroscopy (MS) fourteen cytosolic
TRPA1 cysteines labeled by IA, three of which are required for normal channel
function. In excised patches, reactive compounds activated TRPA1 currents that
were maintained at least 10 min after washout of compound in calcium free solutions.
Finally, activation of TRPA1 by disulfide bond-forming MTSEA is blocked by
the reducing agent dithiothreitol (DTT). Collectively, our data suggest that
covalent modification of reactive cysteines within TRPA1 can cause channel
activation, rapidly signaling potential tissue damage via the pain pathway.
2006 Publications
Macpherons, L.J., Dubin, A.E., Evans, M.J., Marr F., Schultz, P.G., Cravatt,
B.F., Patapoutian, A. (2007) Noxious compounds activate TRPA1 ion channels
through covalent modification of cysteines. Nature 445:541-5
McCleverty CJ, Koesema E, Patapoutian A, Lesley SA, Kreusch A. (2006) Crystal
structure of the human TRPV2 channel ankyrin repeat domain. Protein Sci. 15:2201-6.
Saghatelian A., McKinney, M. K., Bandell, M., Patapoutian, A., Cravatt, B.
F. (2006) A FAAH-regulated class of N-acyl taurines that activates TRP ion
channels. Biochemistry, 45:9007-15.
Macpherson, L.J., Hwang, S.W., Miyamoto, T., Dubin, A. E., Patapoutian, A.,
Story, G.M. (2006) More than cool: Promiscuous relationships of menthol and
other sensory compounds. Molecular and Cellular Neuroscience, 32:335-43.
Bandell, M., Dubin, A.E., Petrus, M.J., Orth, A., Mathur, J., Sun Wook Hwang,
S.W., Patapoutian, A. (2006) High-throughput random mutagenesis screen reveals
TRPM8 residues specifically required for activation by menthol. Nature Neuroscience,
9:493-500.
