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Laminin forms an independent network in basement membranes
P D Yurchenco1, Y S Cheng, H Colognato
1Department of Pathology, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854.
The Journal of Cell Biology
|June 1, 1992
Summary
Laminin forms a self-assembled polymer crucial for basement membrane structure. This laminin network is independent of collagen, with most laminin anchored non-covalently.
Area of Science:
- Biochemistry
- Cell Biology
- Extracellular Matrix Research
Background:
- Laminin is a key component of basement membranes, essential for tissue structure.
- The self-assembly process of laminin and its role in basement membrane organization are not fully understood.
Purpose of the Study:
- To investigate the role of laminin self-assembly in basement membrane integrity.
- To determine how laminin is anchored within basement membranes, particularly in relation to collagen.
Main Methods:
- Investigated laminin self-assembly and basement membrane dissolution using low temperature and EDTA treatments.
- Utilized laminin elastase fragments (E4, E1') as competitive ligands to assess laminin-laminin and laminin-collagen interactions.
- Analyzed supramolecular architecture using freeze-etching and platinum/carbon replication.
- Degraded collagenous networks with bacterial collagenase to study residual laminin anchoring.
Main Results:
- Laminin self-assembly into a polymer is vital for basement membrane structural integrity in embryonal carcinoma cells (ECC).
- Approximately 80% of laminin in Engelbreth-Holm-Swarm (EHS) tumor basement membranes is reversibly anchored via non-covalent interactions.
- Laminin forms a network independent of type IV collagen, with 80% anchored non-covalently and 20% involving laminin-collagen interactions.
Conclusions:
- Laminin self-assembly creates a polymer network essential for basement membrane structure.
- Basement membrane laminin is anchored through both non-covalent interactions and, to a lesser extent, interactions with collagen.