Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Mol Biol Cell. 2006 May;17(5):2346-55. Epub 2006 Mar 8.

Type I collagen in Hsp47-null cells is aggregated in endoplasmic reticulum and deficient in N-propeptide processing and fibrillogenesis.

Author information

  • 1Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8397, Japan.

Abstract

Heat-shock protein of 47 kDa (Hsp47) is a molecular chaperone that recognizes collagen triple helices in the endoplasmic reticulum (ER). Hsp47-knockout mouse embryos are deficient in the maturation of collagen types I and IV, and collagen triple helices formed in the absence of Hsp47 show increased susceptibility to protease digestion. We show here that the fibrils of type I collagen produced by Hsp47-/- cells are abnormally thin and frequently branched. Type I collagen was highly accumulated in the ER of Hsp47-/- cells, and its secretion rate was much slower than that of Hsp47+/+ cells, leading to accumulation of the insoluble aggregate of type I collagen within the cells. Transient expression of Hsp47 in the Hsp47-/- cells restored normal extracellular fibril formation and intracellular localization of type I collagen. Intriguingly, type I collagen with unprocessed N-terminal propeptide (N-propeptide) was secreted from Hsp47-/- cells and accumulated in the extracellular matrix. These results indicate that Hsp47 is required for correct folding and prevention of aggregation of type I collagen in the ER and that this function is indispensable for efficient secretion, processing, and fibril formation of collagen.

PMID:
16525016
[PubMed - indexed for MEDLINE]
PMCID:
PMC1446091
Free PMC Article

Images from this publication.See all images (6)Free text

Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk