Laminin 2026-11-05
A laminin is a large extracellular glycoprotein of the basement membrane, the specialized extracellular matrix underlying many epithelial sheets and surrounding some individual cells. A laminin molecule contains three different polypeptide chains, conventionally called alpha, beta and gamma, assembled into an extended cross-like or related shape. Different chain combinations produce distinct laminins.[ref]
Molecular Biology of the Cell, 4th edition by Bruce Alberts and others. Chapter 19, Basal Laminae Are Composed Mainly of Type IV Collagen, Laminin, Nidogen, and a Heparan Sulfate Proteoglycan
Laminin links matrix organization to cellular behaviour: binding to cell adhesion receptors such as integrins helps a cell attach to its surroundings and orient its surfaces. Its location was established experimentally, not inferred from the name. In 1979, R. Timpl and colleagues isolated laminin from a mouse tumour producing abundant basement membrane material, then used antibodies to localize the isolated component in basement membranes.[ref]
Laminin--a glycoprotein from basement membranes by R. Timpl and others. Abstract and pp. 9933–9937
R. Timpl 2026-11-05
R. Timpl coauthored the 1979 isolation and characterization of laminin, a large glycoprotein associated with basement membranes. The researchers isolated it from a mouse tumour producing abundant basement-membrane material and used antibodies to investigate its distribution.[ref]
Laminin--a glycoprotein from basement membranes by R. Timpl and others. Abstract and pp. 9933–9937: isolation, biochemical characterization and immunological localization
Purification and localization answer complementary questions. Purification establishes a distinguishable molecular component; localization connects that component with a tissue structure. Finding both laminin and type IV collagen in the material helped show that a basement membrane is an organized extracellular assembly, rather than a layer made of one interchangeable protein.