| Autor: |
Sigle RO; Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue, Seattle, WA 98109, USA., Gil SG, Bhattacharya M, Ryan MC, Yang TM, Brown TA, Boutaud A, Miyashita Y, Olerud J, Carter WG |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of cell science [J Cell Sci] 2004 Sep 01; Vol. 117 (Pt 19), pp. 4481-94. Date of Electronic Publication: 2004 Aug 17. |
| DOI: |
10.1242/jcs.01310 |
| Abstrakt: |
In epidermal wounds, precursor laminin 5 (alpha3beta3gamma2) is deposited in the provisional basement membrane (PBM) before other BM components. Precursor laminin 5 contains G4/5 globular domains at the carboxyl terminus of the alpha3 chain. Here, the function of G4/5 was evaluated in deposition of laminin 5. Soluble laminin 5, secreted by keratinocytes in culture, is cleaved by an endogenous protease releasing G4/5. Thrombin, a serum protease, cleaves G4/5 indistinguishably from endogenous protease. Soluble human precursor laminin 5, but not cleaved laminin 5, was bound and deposited by mouse keratinocytes null for mouse alpha3 chain (alpha3-/- MKs). The deposition rescued adhesion and spreading and survival. In a model for PBM assembly, precursor laminin 5 was deposited along fibronectin fibrils at the junction between co-cultures of keratinocytes and fibroblasts. In both models, the deposition of precursor laminin 5 was inhibited by removal of G4/5 with thrombin. To confirm that G4/5 participates in deposition, the human LAMA3A gene was modified to produce alpha3 chains either without or with G4/5 that cannot be cleaved. Both precleaved and noncleavable alpha3 isoforms were expressed in alpha3-/- MKs, where they deposited sufficiently to rescue adhesion via integrins alpha3beta1 and alpha6beta4. Despite this similarity, noncleavable laminin 5 was at least threefold more efficiently deposited than precleaved isoform. We conclude that the G4/5 domain in the alpha3 chain facilitates deposition of precursor laminin 5 into the PBM in epidermal wounds. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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