摘要：

Mammalian channels form a large family with around thirty members. From sequence similarity, can be divided into three major subfamilies: the classical or canonical subfamily (), the melastatin-related subfamily (TRPM), and the vanilloid-receptor–related subfamily (TRPV) [1]. In addition, there are a number of more distantly related subfamilies: TRPA (ankyrin), TRPP (polycystin), and TRPML () [1–3]. , the first member of the TRPV family and the sensory neuron receptor for vanilloid ligands like , which is also responsive to noxious heat (>42°C), was found by expression cloning [4], as were the more distantly related epithelial Ca(2+) channels [5] and [6]. The other members, [7], (see below), and later [8–10], were found by homology screens. was found by screening expressed sequence tag databases for sequences with similarity to , , and the TRPV isoform -9. Lacking a consensus on nomenclature at the time, was given a variety of names—(-9-like channel 4) [11], (vanilloid receptor–related osmotically activated channel) [12], [13] and (vanilloid receptor–like channel 2) [14]—by the different groups who cloned the channel. has 871 amino acids, and structural features of the channel are N- and C-termini, six spanning segments (S1–S6), a reentrant -forming loop between S5 and S6, and at least three ankyrin domains in the cytosolic N-terminus (see, e.g., Figure 9.2). Even though shows sequence similarity to other members of the TRPV family, particularly to –3, a coexpression study has indicated that preferentially forms homomers [15], and, as yet, there is no evidence for heteromultimeric combinations with other TRPVs.

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