Polarized Expression of HD1: Relationship with the Cytoskeleton in Cultured Human Colonic Carcinoma Cells

• Published in: Experimental cell research Vol. 231; no. 2; pp. 319 - 327
• Main Authors: Fontao, L., Dirrig, S., Owaribe, K., Kedinger, M., Launay, J.F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.03.1997
• Subjects: Actins - analysis; Adenocarcinoma - metabolism; Adenocarcinoma - pathology; Cell Adhesion; Cell Differentiation; Cell Polarity; Colonic Neoplasms - metabolism; Colonic Neoplasms - pathology; Cytochalasin B - pharmacology; Cytoskeleton - drug effects; Cytoskeleton - metabolism; Gene Expression Regulation, Neoplastic; Homeodomain Proteins - biosynthesis; Homeodomain Proteins - genetics; Humans; Intermediate Filament Proteins - biosynthesis; Intermediate Filament Proteins - genetics; Intermediate Filaments - metabolism; Keratins - metabolism; Neoplasm Proteins - biosynthesis; Neoplasm Proteins - genetics; Organelles - metabolism; Organelles - ultrastructure; Tumor Cells, Cultured - drug effects; Vinblastine - pharmacology
• ISSN: 0014-4827; 1090-2422
• DOI: 10.1006/excr.1996.3465

Hemidesmosomes (HDs) mediate adhesion of epithelial cells to the extracellular matrix and have morphological associations with intermediate-size filaments (IFs). Hemidesmosomal molecular components including HD1, the two bullous pemphigoid antigens, and the integrin α6β4 have been identified in HDs of stratified and complex epithelium. In this study, we report that HT29-Fu cells, a human colonic tumor cell line, express two hemidesmosomal components (HD1, α6β4) associated in an adhesion structure termed type II HDs. Immunofluorescence studies showed a colocalization of HD1 and α6β4 in basal patches between actin stress fibers. Using cytochalasin B or vinblastine, two drugs which disrupt the cytoskeleton, we demonstrate that the redistribution of HD1 was probably induced by the reorganization of the basal cytokeratin network. We also show thatin vitroHD1 binds to polymerized cytokeratin intermediate filaments; this suggests that HD1 in intestinal epithelial cells functions as a linker protein connecting cytokeratin filaments to the basal plasma membrane, probably through the β4 subunit of the integrin α6β4.