Dynamics of Contacts between Lamellae of Fibroblasts: Essential Role of the Actin Cytoskeleton

• Published in: Proceedings of the National Academy of Sciences - PNAS 1998-04, Vol.95 (8), p.4362-4367
• Main Authors: Gloushankova, N. A., Krendel, M. F., Alieva, N. O., Bonder, E. M., Feder, H. H., Vasiliev, J. M., Gelfand, I. M.
• Format: Article
• Language: English
• Subjects: Actins; Actins - physiology; Animals; beta Catenin; Biological Sciences; Cadherins - analysis; Cell adhesion; Cell Communication - physiology; Cell Line; Cell lines; Cells; Cellular biology; Cytoskeletal Proteins - analysis; Cytoskeleton - physiology; Diacetyl - analogs & derivatives; Diacetyl - pharmacology; Epithelial cells; Fibroblasts; Fibroblasts - cytology; Fibroblasts - physiology; Fibrosis; Humans; Intercellular Junctions - physiology; Intercellular Junctions - ultrastructure; Microfilaments; Microscopy; Molecules; Myosins - antagonists & inhibitors; Myosins - physiology; Rats; Trans-Activators
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.95.8.4362

We investigated actin cytoskeletal and adhesion molecule dynamics during collisions of leading lamellae of nontransformed and oncogene-transformed fibroblasts. By using real-time video microscopy, it was found that during lamellar collision there was considerable overlapping of leading lamellae followed by subsequent retraction. Overlapping of nontransformed fibroblasts was accompanied by formation of β -catenin-positive contact structures organized into strands oriented parallel to the long axis of the cell that were associated with bundles of actin filaments. Maintenance of such cell-cell contact structures critically depended on the contractility of actin cytoskeleton, as inhibition of contractility with serum-free medium or 2,3-butanedione 2-monoxime (BDM) resulted in loss of strand formation. Strand formation was recovered when cells in serum-free medium were incubated with the microtubule inhibitor nocodazole, which is known to increase contractility. Oncogene-transformed fibroblasts reacted to collisions with responses similar to non-transformed fibroblasts but did not develop well-organized cell-cell contacts. A model is presented to describe how differences in the organization of the actin cytoskeleton could account for the structurally distinct responses to cell-cell contact by polarized fibroblastic cells versus nonpolarized epithelial cells.