Human amnion contains a novel laminin variant, laminin 7, which like laminin 6, covalently associates with laminin 5 to promote stable epithelial-stromal attachment.
J Cell Biol
; 132(6): 1189-98, 1996 Mar.
Article
em En
| MEDLINE
| ID: mdl-8601594
ABSTRACT
Stable attachment of external epithelia to the basement membrane and underlying stroma is mediated by transmembrane proteins such as the integrin alpha6beta4 and bullous pemphigoid antigen 2 within the hemidesmosomes along the basolateral surface of the epithelial cell and their ligands that include a specialized subfamily of laminins. The laminin 5 molecule (previously termed kalinin/nicein/epiligrin) is a member of this epithelial-specific subfamily. Laminin 5 chains are not only considerably truncated within domains III-VI, but are also extensively proteolytically processed in vitro and in vivo. As a result, the domains expected to be required for the association of laminins with other basement membrane components are lacking in the mature laminin 5 molecule. Therefore, the tight binding of laminin 5 to the basement membrane may occur by a unique mechanism. To examine laminin 5 in tissue, we chose human amnion as the source, because of its availability and the similarity of the amniotic epithelial basement membrane with that of skin. We isolated the laminin 5 contained within the basement membrane of human amnion. In addition to monomeric laminin 5, we find that much of the laminin 5 isolated is covalently adducted with laminin 6 (alpha3beta1gamma1) and a novel laminin isotype we have termed laminin 7 (alpha3beta2gamma1). We propose that the association between laminin 5 and laminins 6 and 7 is a mechanism used in amnion to allow stable association of laminin 5 with the basement membrane. The beta2 chain is seen at the human amniotic epithelial-stromal interface and at the dermal-epidermal junction of fetal and adult bovine skin by immunofluorescence, but is not present, or only weakly present, in neonatal human skin.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Adesão Celular
/
Laminina
/
Âmnio
Tipo de estudo:
Risk_factors_studies
Limite:
Adult
/
Animals
/
Humans
/
Newborn
Idioma:
En
Revista:
J Cell Biol
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Estados Unidos