TRP Channels


The first member of the transient receptor potential (TRP) ion channels was identified as a key component of phototransduction in the fly photoreceptor. Since that time, 28 mammalian members of the family have been identified, many of which play important roles in sensory physiology. Most remarkably, some of these channels are directly gated by temperature.

Keywords: ion channel; temperature; sensory; phospholipase C; calcium

Figure 1.

Sensory transduction with TRPs. (a) G protein‐coupled receptor activates phospholipase C (PLC), which catalyses the hydrolysis of phosphatidyl inositol(4,5)bisphosphate to inositol trisphosphate (IP3) and DAG. In the photoreceptor, TRP and TRPL channels are activated downstream of this signalling pathway, and they carry inward current that depolarizes the cell. In the VNO‐sensory neuron, TRPC2 is activated downstream of this signalling cascade. In both cases, transduction occurs on microvilli devoid of Ca2+ store. (b) In taste cells, a similar signalling pathway leads to release of Ca2+ from intracellular stores. TRPM5 channels are distributed throughout the plasma membrane and are gated by the elevation of intracellular Ca2+.

Figure 2.

Family of TRP channels. Homology relationships among the 28 mammalian TRP channels. For comparison, the relationship with the two Drosophila channels and the TRPN channel from zebrafish is shown. Colours indicate the grouping of subfamily members.

Figure 3.

Thermo TRPs. (a) Approximate temperature range over which different thermo TRPs are active. (b) Bottom panel shows the electrical response of a cold‐activated channel (TRPM8) and warm‐activated channel (TRPV1). Both channels carry an inward current at the resting potential of the cell, but have opposite responses to temperature.



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Further Reading

Dhaka A, Viswanath V and Patapoutian A (2006) Trp ion channels and temperature sensation. Annual Review of Neuroscience 29: 135–161.

Hardie RC and Raghu P (2001) Visual transduction in Drosophila. Nature 413: 186–193.

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Stowers L, Holy TE, Meister M et al. (2002) Loss of sex discrimination and male–male aggression in mice deficient for TRP2. Science 295: 1493–1500.

Voets T, Droogmans G, Wissenbach U et al. (2004) The principle of temperature‐dependent gating in cold‐ and heat‐sensitive TRP channels. Nature 430: 748–754.

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How to Cite close
Liman, Emily R(Sep 2007) TRP Channels. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0020292]