| First Author | Krug SM | Year | 2012 |
| Journal | Cell Mol Life Sci | Volume | 69 |
| Issue | 16 | Pages | 2765-78 |
| PubMed ID | 22402829 | Mgi Jnum | J:345439 |
| Mgi Id | MGI:7606440 | Doi | 10.1007/s00018-012-0949-x |
| Citation | Krug SM, et al. (2012) Claudin-17 forms tight junction channels with distinct anion selectivity. Cell Mol Life Sci 69(16):2765-78 |
| abstractText | Barrier properties of tight junctions are determined by the claudin protein family. Many claudins seal this barrier, but others form paracellular channels. Among these, no claudins with general and clear-cut anion selectivity have yet been described, while for claudin-10a and claudin-4, only circumstantial or small anion selectivities have been shown. A claudin with unknown function and tissue distribution is claudin-17. We characterized claudin-17 by overexpression and knock-down in two renal cell lines. Overexpression in MDCK C7 cell layers caused a threefold increase in paracellular anion permeability and switched these cells from cation- to anion-selective. Knockdown in LLC-PK(1) cells indorsed the finding of claudin-17-based anion channels. Mutagenesis revealed that claudin-17 anion selectivity critically depends on a positive charge at position 65. Claudin-17 expression was found in two organs: marginal in brain but abundant in kidney, where expression was intense in proximal tubules and gradually decreased towards distal segments. As claudin-17 is predominantly expressed in proximal nephrons, which exhibit substantial, though molecularly not defined, paracellular chloride reabsorption, we suggest that claudin-17 has a unique physiological function in this process. In conclusion, claudin-17 forms channels within tight junctions with distinct anion preference. |
