Claudin-16 and claudin-19 interact and form a cation-selective tight junction complex
Jianghui Hou, … , Siegfried Waldegger, Daniel A. Goodenough
Jianghui Hou, … , Siegfried Waldegger, Daniel A. Goodenough
Published January 10, 2008
Citation Information: J Clin Invest. 2008;118(2):619-628. https://doi.org/10.1172/JCI33970.
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Research Article Nephrology

Claudin-16 and claudin-19 interact and form a cation-selective tight junction complex

Abstract

Tight junctions (TJs) play a key role in mediating paracellular ion reabsorption in the kidney. Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is an inherited disorder caused by mutations in the genes encoding the TJ proteins claudin-16 (CLDN16) and CLDN19; however, the mechanisms underlying the roles of these claudins in mediating paracellular ion reabsorption in the kidney are not understood. Here we showed that in pig kidney epithelial cells, CLDN19 functioned as a Cl– blocker, whereas CLDN16 functioned as a Na+ channel. Mutant forms of CLDN19 that are associated with FHHNC were unable to block Cl– permeation. Coexpression of CLDN16 and CLDN19 generated cation selectivity of the TJ in a synergistic manner, and CLDN16 and CLDN19 were observed to interact using several criteria. In addition, disruption of this interaction by introduction of FHHNC-causing mutant forms of either CLDN16 or CLDN19 abolished their synergistic effect. Our data show that CLDN16 interacts with CLDN19 and that their association confers a TJ with cation selectivity, suggesting a mechanism for the role of mutant forms of CLDN16 and CLDN19 in the development of FHHNC.

Authors

Jianghui Hou, Aparna Renigunta, Martin Konrad, Antonio S. Gomes, Eveline E. Schneeberger, David L. Paul, Siegfried Waldegger, Daniel A. Goodenough

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Figure 2

CLDN16 interacts with CLDN19 in yeast.

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CLDN16 interacts with CLDN19 in yeast. (A) Y2H assays showing interactio...
(A) Y2H assays showing interaction of CLDN16-WT with CLDN19-WT and CLDN19-WT with CLDN19-WT, but not of CLDN16-WT with CLDN16-WT. Shown are plates with selective medium lacking leucine and tryptophan (–LW), indicating the transforming of both bait and prey vectors; with SD-LWHA, indicating the expression of reporter genes HIS3 and ADE2; and β-galactosidase assay (A615 values) for quantification of interaction strength. (B) Mutations in CLDN19 affecting its homomeric interaction. (C) Mutations in CLDN19 affecting its heteromeric interaction with CLDN16. (D) Mutations in CLDN16 affecting its heteromeric interaction with CLDN19.