Format

Send to

Choose Destination
Curr Biol. 2017 Dec 18;27(24):3783-3795.e8. doi: 10.1016/j.cub.2017.11.014. Epub 2017 Dec 5.

Tension-Dependent Stretching Activates ZO-1 to Control the Junctional Localization of Its Interactors.

Author information

1
Department of Cell Biology, Faculty of Sciences, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland; Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland.
2
Department of Physics, National University of Singapore, 5A Engineering Drive 1, Singapore 117411, Singapore; Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore 117411, Singapore.
3
EPFL School of Life Sciences PTBIOP, Station 19, 1015 Lausanne, Switzerland.
4
Department of Cell Biology, Faculty of Sciences, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland; Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland. Electronic address: sandra.citi@unige.ch.

Abstract

Tensile forces regulate epithelial homeostasis, but the molecular mechanisms behind this regulation are poorly understood. Using structured illumination microscopy and proximity ligation assays, we show that the tight junction protein ZO-1 exists in stretched and folded conformations within epithelial cells, depending on actomyosin-generated force. We also show that ZO-1 and ZO-2 regulate the localization of the transcription factor DbpA and the tight junction membrane protein occludin in a manner that depends on the organization of the actin cytoskeleton, myosin-II activity, and substrate stiffness, resulting in modulation of gene expression, cell proliferation, barrier function, and cyst morphogenesis. Pull-down experiments show that interactions between N-terminal (ZPSG) and C-terminal domains of ZO-1 prevent binding of DbpA to the ZPSG, suggesting that force-dependent intra-molecular interactions regulate ZPSG binding to ligands within cells. In vivo and in vitro experiments also suggest that ZO-1 heterodimerization with ZO-2 promotes the stretched conformation and ZPSG interaction with ligands. Magnetic tweezers single-molecule experiments suggest that pN-scale tensions (∼2-4 pN) are sufficient to maintain the stretched conformation of ZO-1, while keeping its structured domains intact, and that 5-20 pN force is required to disrupt the interaction between the extreme C-terminal and the ZPSG domains of ZO-1. We propose that tensile forces regulate epithelial homeostasis by activating ZO proteins through stretching, to control the junctional recruitment and downstream signaling of their interactors.

KEYWORDS:

DbpA; ZO-1; ZO-2; ZO-3; ZONAB; actomyosin; conformation; force; occludin; tight junction

PMID:
29199076
DOI:
10.1016/j.cub.2017.11.014
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center