Evaluating Physiological and Organizational Properties of the Tight Junction ZO-1 ZU-5 Domain in MDCK Cells

Abstract

Zonula occludens-1 (ZO-1) is an essential TJ component contributing to junctional formation by mediating interactions between junctional proteins and the actomyosin cytoskeleton. MDCK II cells, a model epithelial cell line, with ZO-1 knocked-out (ZO-1 KO) have observable phenotypic changes such as alterations in the actin cytoskeletal organization and physiological barrier properties. This study focuses on the ZO-1-ZU5 domain by rescuing ZO-1 with full-length and a panel of ZO-1-ZU5 mutants. ZO-1-ZU-5 is known to bind cingulin and through this interaction ZO-1 adopts an extended conformation. We examined actomyosin cytoskeleton organization, ZO-1 mobility, gene expression and barrier function to determine whether the ZO-1-ZU5 mutants rescue full-length activity. We found that the ZO-1- ZU5 truncation mutant cell line rescued transepithelial electrical resistance (TER) but did not rescue tight junction distribution or the amount of total gamma-actin. We will present evaluation of additional ZU5 mutants. This study expands our understanding of how extended ZO-1 regulates the mechanical, genetic, and phenotypic properties of epithelial cells. Trinity University Biology Summer Undergraduate Research Fellowship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.