IBIS-Flora

Angiosperm Flora of India

Effects of Endosomal Photodamage on Membrane Recycling and Endocytosis

Publication Type:Journal Article
Year of Publication:2011
Authors:Andrzejak, M, Santiago, M, Kessel, D
Journal:Photochemistry and Photobiology
Volume:87
Issue:3
Date Published:2011
ISBN Number:1751-1097
Abstract:

The flux of receptor-independent endocytosis can be estimated by addition of wortmannin to cell cultures. Membrane influx is unaffected but traffic out of late endosomes is impaired, resulting in a substantial enlargement of these organelles. Using the 1c1c7 murine hepatoma, we investigated the effect of endosomal photodamage on this endocytic pathway. We previously reported that photodamage catalyzed by the lysosomal photosensitizer NPe6 prevented wortmannin-induced endosomal swelling, indicating an earlier block in the process. In this study, we show that endosomal photodamage, initiated by photodamage from an asymmetrically substituted porphine or a phthalocyanine also prevents wortmannin-induced endosomal swelling, even when the photodynamic therapy (PDT) dose is insufficient to cause endosomal disruption. As the PDT dose is increased, endosomal breakage occurs, as does apoptosis and cell death. Very high PDT doses result in necrosis. We propose that photodamage to endosomes results in alterations in the endosomal structure such that influx of new material is inhibited and receptor-independent endocytosis is prevented. In an additional series of studies, we found that the swollen late endosomes induced by wortmannin are unable to retain previously accumulated fluorescent probes or photosensitizers.

URL:http://dx.doi.org/10.1111/j.1751-1097.2011.00890.x
Short Title:Photochemistry and Photobiology
Fri, 2014-01-24 22:09 -- admin
https://secure.gravatar.com/avatar/5ade1b012674ce3dd941e2ea5dd15cc1.jpg?d=https%3A//flora.indianbiodiversity.org/sites/all/modules/patches/contrib/gravatar/avatar.png&s=100&r=G
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith