Cell-to-cell adherens junction formation and actin filament organization: similarities and differences between non-polarized fibroblasts and polarized epithelial cells

S Yonemura, M Itoh, A Nagafuchi… - Journal of cell …, 1995 - journals.biologists.com
S Yonemura, M Itoh, A Nagafuchi, S Tsukita
Journal of cell science, 1995journals.biologists.com
Cadherin has an intimate spatial relationship with actin filaments (AF) in various types of
cells, forming the cell-to-cell adherens junction (AJ). We compared the AJ/AF rela-tionship
between non-polarized fibroblasts (NRK cells) and polarized epithelial cells (MTD-1A cells).
E/P-cadherin, α-catenin, ZO-1 and vinculin were localized with reference to AF in these cells
using laser scan microscopy as well as conventional light and electron microscopy. NRK
cells adhered to each other at the tips of thin cellular processes, where spot-like AJ were …
Abstract
Cadherin has an intimate spatial relationship with actin filaments (AF) in various types of cells, forming the cell-to-cell adherens junction (AJ). We compared the AJ/AF rela-tionship between non-polarized fibroblasts (NRK cells) and polarized epithelial cells (MTD-1A cells). E/P-cadherin, α-catenin, ZO-1 and vinculin were localized with reference to AF in these cells using laser scan microscopy as well as conventional light and electron microscopy. NRK cells adhered to each other at the tips of thin cellular processes, where spot-like AJ were formed, where P-cadherin, α-catenin, ZO-1 and vinculin were concentrated. Some stress-fiber-like AF bundles ran axially in these processes and terminated at spot-like AJ on their tips. At the electron micro-scopic level these spot-like AJ were seen as aggregates of small ‘units’ of AJ, where AF were densely and perpendicularly associated with the plasma membrane. In MTD-1A cells, the AJ/AF relationship was investigated during the cell polarization process after replating or wounding. At the early stage, the AJ/AF relationship was quite similar to that in NRK cells. As polarization proceeded, the spot-like AJs were gradually fused side by side with the concomitant shortening of the associated stress-fiber-like AF bundles. Finally, the belt-like AJ was established, which was lined with circumferential AF bundles. The similarities and differences in the AJ/AF relationship between non-polarized fibroblasts and polarized epithelial cells are discussed.
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