Collagen fibrillogenesis: fibronectin, integrins, and minor collagens as organizers and nucleators.
Curr Opin Cell Biol
; 20(5): 495-501, 2008 Oct.
Article
in En
| MEDLINE
| ID: mdl-18640274
ABSTRACT
Collagens are triple helical proteins that occur in the extracellular matrix (ECM) and at the cell-ECM interface. There are more than 30 collagens and collagen-related proteins but the most abundant are collagens I and II that exist as D-periodic (where D = 67 nm) fibrils. The fibrils are of broad biomedical importance and have central roles in embryogenesis, arthritis, tissue repair, fibrosis, tumor invasion, and cardiovascular disease. Collagens I and II spontaneously form fibrils in vitro, which shows that collagen fibrillogenesis is a selfassembly process. However, the situation in vivo is not that simple; collagen I-containing fibrils do not form in the absence of fibronectin, fibronectin-binding and collagen-binding integrins, and collagen V. Likewise, the thin collagen II-containing fibrils in cartilage do not form in the absence of collagen XI. Thus, in vivo, cellular mechanisms are in place to control what is otherwise a protein self-assembly process. This review puts forward a working hypothesis for how fibronectin and integrins (the organizers) determine the site of fibril assembly, and collagens V and XI (the nucleators) initiate collagen fibrillogenesis.
Full text:
1
Database:
MEDLINE
Main subject:
Integrins
/
Collagen
/
Fibronectins
/
Protein Isoforms
Limits:
Animals
/
Humans
Language:
En
Year:
2008
Type:
Article