Display Settings:


Send to:

Choose Destination
See comment in PubMed Commons below
Autophagy. 2009 Nov;5(8):1180-5. Epub 2009 Nov 8.

3D tomography reveals connections between the phagophore and endoplasmic reticulum.

Author information

  • 1University of Helsinki, Department of Biological and Environmental Sciences, Division of Biochemistry, Helsinki, Finland.


Autophagosomes have been reported to form in the vicinity of the endoplasmic reticulum (ER). In many cases, the phagophore membrane is observed between two cisternae of rough ER, but it is not known whether these two membranes are directly connected. To investigate the relationship of the phagophore membrane and the ER, we used electron microscopic tomography of serum and amino acid starved normal rat kidney cells. The cells were fixed in glutaraldehyde and reduced osmium tetroxide and embedded in Epon. Dual axis tilt image series were acquired from two successive 250-nm sections. To analyze the three-dimensional (3D) morphology of phagophores and the associated rough ER, 3D tomograms were used to model the ER and phagophore membranes. The tomographic reconstructions revealed connections between the phagophore/autophagosome membrane and the closely located ER cisternae, especially with the ER located inside the autophagosome. The connections were typically formed by narrow extensions from the phagophore/autophagosome to the ER. This finding has potential implications on the origin of autophagosome membranes, and on the mechanism of phagophore membrane extension. In addition, we observed lipid droplets in very close contact with the phagophores/autophagosomes.

[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Landes Bioscience
    Loading ...
    Write to the Help Desk