Assembly of laminin polymers is dependent on beta1-integrins

Exp Cell Res. 2001 Apr 15;265(1):135-44. doi: 10.1006/excr.2001.5170.


Recent reports suggest that laminin deposition is controlled by the cell via specific receptors, one of which is dystroglycan. In this study, the involvement of beta1-integrins in this process was investigated by comparing beta1-integrin-deficient cells of different phenotypes with their normal counterparts. Normal embryonic stem (ES) cells and embryoid bodies (EBs) derived from them were found to deposit cell-associated laminin into fibrillar networks, and in the EBs a basement membrane was assembled under the primitive endoderm. beta1-deficient ES cells and their EBs formed only small amounts of dot-like laminin deposits. Skeletal myotubes formed after prolonged differentiation in EBs were found to be surrounded by laminin, nidogen, and perlecan by immunofluorescent staining irrespective of the presence of beta1-integrins on the myotubes. However, at the electron microscope level only very thin sheet-like structures were detected close to the beta1-deficient myotubes, while the wt myotubes formed thick basement membranes. An epithelial cell line, GE11, derived from the beta1-integrin-deficient ES cells was also unable to assemble laminin on the cell surface, while transfection of the cells with the integrin beta1 subunit resulted in formation of a dense laminin network. Taken together, these results suggest that dystroglycan and beta1-integrins can both contribute to the recruitment of laminin to cell surfaces and that integrins are required at a subsequent step in the formation of basement membranes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism
  • Humans
  • Integrin beta1 / metabolism*
  • Integrin beta1 / physiology
  • Laminin / metabolism*
  • Polymers


  • Integrin beta1
  • Laminin
  • Polymers