TRPP1 channel
| Channel name | TRPP11,2,3,4,5 |
| Description | Nonselective cation channel subunit |
| Other names | PC2, PKD2, TRPP2 |
| Molecular information | Human unigene: Hs0.181272, chr. 4q21–23 |
| Mouse unigene: Mm0.6442, chr. 5 | |
| Associated subunits | PKD1, Hax-1, cortactin, tropomyosin, actin cadherin via PKD1 |
| Functional assays | Patch-clamp, calcium imaging |
| Current | Near linear when coexpressed with PKD1 |
| Conductance | 40pS in high [Ca2+]4, ∼50pS in symmetrical 140 mM K+5 |
| Ion selectivity | PNa/PCa ∼0.7 |
| Activation | Mechanical stress? |
| Inactivation | Not established |
| Gating inhibitors | None |
| Blockers | Amiloride (30 μM), Gd3+, La3+ |
| Radioligands | None |
| Channel distribution | Widely expressed; kidney, pancreas, heart, testis, blood |
| Physiological functions | Mouse cardiac, skeletal, and renal development; kidney and liver cyst formation, with PC2 (PKD2) mechanosensation in cilia (kidney) |
| Mutations and pathophysiology | Not established |
| Comments | Homomeric vs. heteromeric (with PKD1) channel function not clear; note that the nomenclature is not settled by HUGO–here we have grouped only the 6TM subtypes as TRPPs and left the longer (11TMs such as PKD1) polycystins out of the classification |
chr., chromosome; PC2, polycystin-2; PKD2, polycystic kidney disease protein 2; PKD1, polycystin-1.
↵1. Wu G, D'Agati V, Cai Y, Markowitz G, Park JH, Reynolds DM, Maeda Y, Le TC, Hou H Jr, Kucherlapati R, et al. (1998) Somatic inactivation of Pkd2 results in polycystic kidney disease. Cell 93:177-188
↵2. Delmas P (2004) Polycystins: from mechanosensation to gene regulation. Cell 118:145-148
↵3. Tsiokas L, Arnould T, Zhu C, Kim E, Walz G, and Sukhatme VP (1999) Specific association of the gene product of PKD2 with the TRPC1 channel. Proc Natl Acad Sci USA 96:3934-3939
↵4. Gonzalez-Perret S, Kim K, Ibarra C, Damiano AE, Zotta E, Batelli M, Harris PC, Reisin IL, Arnaout MA, and Cantiello HF (2001) Polycystin-2, the protein mutated in autosomal dominant polycystic kidney disease (ADPKD), is a Ca2+-permeable nonselective cation channel. Proc Natl Acad Sci USA 98:1182-1187
↵5. Luo Y, Vassilev PM, Li X, Kawanabe Y, and Zhou J (2003) Native polycystin 2 functions as a plasma membrane Ca2+-permeablecation channel in renal epithelia. Mol Cell Biol 23:2600-2607