Characterization of a tight molecular complex between integrin alpha 6 beta 4 and laminin-5 extracellular matrix.

Autor: Falk-Marzillier J; Department of Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA., Domanico SZ, Pelletier A, Mullen L, Quaranta V
Jazyk: angličtina
Zdroj: Biochemical and biophysical research communications [Biochem Biophys Res Commun] 1998 Oct 09; Vol. 251 (1), pp. 49-55.
DOI: 10.1006/bbrc.1998.9400
Abstrakt: In many adult epithelia, e.g., epidermis or intestine, adhesion of epithelial cells to basement membrane requires the integrin alpha6 beta4 and laminin-5 (Ln-5). In the absence of one or the other, extensive blistering and exfoliation occur. While alpha6 beta4 was reported to be a receptor for Ln-5, this interaction is poorly understood. We characterize complexes between alpha6 beta4 and Ln-5 in cell-free preparations of extracellular matrix (ECM) from the epithelial cell line, 804G. By microsequencing, Ln-5 and alpha6 beta4 were the major proteins in this ECM and were likely engaged in receptor/ligand complexes because, by immunofluorescence, alpha6 beta4 was colocalized with Ln-5 both in cell monolayers and in cell-free ECM preparations, but they disappeared after preincubation of the monolayers with alpha6 beta4 or Ln-5 function-blocking antibodies. The alpha6 beta4/Ln-5 complexes were resistant to dissociation by extreme pH, urea, chaotropes, eDTA, non-ionic detergents, and b-mercaptoethanol. They were only dissociated by strong anionic detergents, e.g., 1% SDS, suggesting receptor/ligand interactions based on high affinity or avidity. We propose that these alpha6 beta4/Ln-5 complexes may provide links between plasma membrane and basement membrane that resist mechanical stress and support epithelial integrity.
(Copyright 1998 Academic Press.)
Databáze: MEDLINE
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