Transient receptor potential channel superfamily

The mammalian transient receptor potential (TRP) superfamily of six transmembrane domain cation channels encompasses 28 members divided into six subfamilies (TRPA, TRPC, TRPM, TRPV, TRPML and TRPP) on the basis of amino acid sequence homology (Clapham et al. 2005 Nilius and Voets 2005 Ramsey et al. 2006). 

A superfamily of cation channels conserved in mammals, flies, worms and yeast. The various TRP-proteins bear-sequence and predicted structural similarities to the founding member of this superfamily, transient receptor-potential (TRP), a light activated cation channel in the Dmsophila photoreceptor. 

Sour taste detects acids, i.e., protons. Several different sour taste receptor candidates such as acid-sensing ion channels (ASICs) (57), hyperpolarization-activated cyclic nucleotide-gated channels (HCNs) (58), and two pore domain potassium channels (K2PS) (59, 60) have been described in the past. In addition, recent research identified two members of the polycystic kidney disease (PKD) family of the transient receptor potential superfamily (TRP) as strong sour taste receptor candidates or as part thereof. Immunohistochemistry and in situ hybridization revealed the presence of the polycystic-kidney-disease-like ion channel PKD2L1 in subsets of taste receptor cells of mouse fungiform, vallate, and foliate papillae. These cells differ from... 

Vitamin D-mediated transcellular calcium transport also involves entry and extmsion. Calcium influx from the intestine or bone is propelled by a steep electrochemical gradient mediated by the superfamily of Transient Receptor Potential (TRP) ion channels noted above. TRP channel ion selectivity and mode of activation are extremely variable. Some are activated or regulated by ligands such as amino acid amines or small peptides, others by physical stimuli (e.g., heat), and still others by as yet unknown mechanisms. All TRP channels are Ca2+ and Na+ selective, but the selectivity for Ca2+ versus Na+ (Ca/Na ratio) varies enormously from >100 1, to <0.05 1. This variability has contributed to a confusing TRP channel nomenclature. 

Arguably one of the most interesting targets in the past decade has been the family known as the transient receptor potential (TRP) channels (Figure 108.1). They compose a superfamily of ion channels that play important roles in the transmission... 

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