The Dermal-Epidermal Junction of Human Skin Contains a Novel Laminin Variant

• Published in: The Journal of cell biology 1992-11, Vol.119 (3), p.695-703
• Main Authors: Marinkovich, M. Peter, Lunstrum, Gregory P., Keene, Douglas R., Burgeson, Robert E.
• Format: Article
• Language: English
• Subjects: Antibodies; Basement membrane; Basement Membrane - chemistry; Basement Membrane - ultrastructure; Biological and medical sciences; Blotting, Western; Cells, Cultured; Cellular biology; Cross Reactions; Cultured cells; Epidermal Cells; Epidermis - chemistry; Epithelial cells; Epitopes - analysis; Fundamental and applied biological sciences. Psychology; Gels; Genetic Variation; Humans; Infant, Newborn; Keratinocytes; Keratinocytes - chemistry; Keratinocytes - cytology; Laminin - analysis; Laminin - genetics; Laminin - immunology; Macromolecular Substances; Male; Molecular chains; Molecular Weight; Molecules; Organ Specificity; Peripheral Nerves - cytology; Skin; Skin - chemistry; Skin - cytology; Squamous cell carcinoma; Vertebrates: skin, associated glands, phaneres, light organs, various exocrine glands (salt gland, uropygial gland...), adipose tissue, connective tissue
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.119.3.695

We report the identification of a novel laminin variant that appears to be unique to a subset of epithelial basement membranes. The variant contains two chains electrophoretically and immunologically identical to the B1 and B2 chains. Epitopes contained in the laminin A chain are absent from the molecule, and a 190-kD chain substitutes for the A chain. V8 protease analysis and Western blotting studies indicate that the variant 190-kD chain shows structural and immunological similarity to the 200-kD chain of kalinin. Rotary shadowing analysis indicates that the 190-kD chain contributes a large globular structure to the variant long arm, but lacks the short arm contributed to laminin by the A chain. The variant is produced by cultured skin explants, human keratinocytes and a squamous cell carcinoma line, and is present in human amniotic fluid. Polyclonal antibodies raised to kalinin, a recently characterized novel component of anchoring filaments, and mAb BM165 which recognizes a subunit of kalinin (Rousselle et al., 1991) cross react with the variant under nonreducing conditions. Immuno-histological surveys of human tissues using the cross-reacting antikalinin antiserum indicate that the distribution of this laminin variant is at least restricted to anchoring filament containing basement membranes. We propose the name K-laminin for this variant.