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Morphologic determinant of tight junctions revealed by claudin-3 structures.
Shun Nakamura1,2, Katsumasa Irie1,2, Hiroo Tanaka3
1Cellular and Structural Physiology Institute, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan.
Nature Communications
|February 20, 2019
Summary
The crystal structure of claudin-3 reveals a bent third transmembrane helix, impacting tight junction strand morphology and adhesiveness. This finding provides a model for diverse tight junction strand formations in epithelia.
Area of Science:
- Cell Biology
- Structural Biology
- Biochemistry
Background:
- Tight junctions are crucial cell adhesion structures in epithelia, regulating paracellular transport.
- Claudins are the primary protein components of tight junctions, forming polymerised strands with varied structures and functions.
Purpose of the Study:
- To determine the crystal structure of mammalian claudin-3.
- To investigate the structural basis for tight junction strand morphology and function.
Main Methods:
- X-ray crystallography at 3.6 Å resolution.
- Structural analysis of claudin-3 and its mutants.
Main Results:
- The crystal structure of claudin-3 shows a distinct bent conformation in its third transmembrane helix.
- Mutational analysis indicates that helix conformation (bent or straight) is residue-dependent.
- Helix conformation influences claudin-claudin interactions and the resulting tight junction strand morphology and adhesiveness.
Conclusions:
- The study presents a structural model for tight junction strand formation, explaining the observed straight and curvy morphologies.
- The findings highlight the role of claudin helix structure in regulating tight junction barrier and channel functions.
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