JCB logo
MBL International Tel: 800.200.5459 CLICK HERE
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
Published online 24 January 2005. doi:10.1083/jcb.200407078
The Rockefeller University Press, 0021-9525 $8.00
JCB, Volume 168, Number 3, 465-476
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 5682K)
Right arrow PPT slides of all figures
Right arrow Supplemental Material Index
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kirkham, M.
Right arrow Articles by Parton, R. G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kirkham, M.
Right arrow Articles by Parton, R. G.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

Article

 Ultrastructural identification of uncoated caveolin-independent early endocytic vehicles

Matthew Kirkham1,2,3, Akikazu Fujita1,2,3, Rahul Chadda6, Susan J. Nixon1,2,3, Teymuras V. Kurzchalia4, Deepak K. Sharma5, Richard E. Pagano5, John F. Hancock1, Satyajit Mayor6, and Robert G. Parton1,2,3

1 Institute for Molecular Bioscience, University of Queensland, Queensland 4072, Australia
2 Centre for Microscopy and Microanalysis, University of Queensland, Queensland 4072, Australia
3 School of Biomedical Sciences, University of Queensland, Queensland 4072, Australia
4 Max Planck Institute for Molecular Cell Biology and Genetics, Dresden D-01307, Germany
5 Department of Biochemistry and Molecular Biology, Mayo Clinic and Foundation, Rochester, MN 55905
6 National Centre for Biological Sciences, Bangalore, 560 065, India

Correspondence to Robert G. Parton: R.Parton{at}imb.uq.edu.au

Using quantitative light microscopy and a modified immunoelectron microscopic technique, we have characterized the entry pathway of the cholera toxin binding subunit (CTB) in primary embryonic fibroblasts. CTB trafficking to the Golgi complex was identical in caveolin-1null (Cav1–/–) mouse embryonic fibroblasts (MEFs) and wild-type (WT) MEFs. CTB entry in the Cav1–/– MEFs was predominantly clathrin and dynamin independent but relatively cholesterol dependent. Immunoelectron microscopy was used to quantify budded and surface-connected caveolae and to identify noncaveolar endocytic vehicles. In WT MEFs, a small fraction of the total Cav1-positive structures were shown to bud from the plasma membrane (2% per minute), and budding increased upon okadaic acid or lactosyl ceramide treatment. However, the major carriers involved in initial entry of CTB were identified as uncoated tubular or ring-shaped structures. These carriers contained GPI-anchored proteins and fluid phase markers and represented the major vehicles mediating CTB uptake in both WT and caveolae-null cells.

D.K. Sharma's present address is Photometrics, Roper Scientific, Tucson, AZ 85706.

Abbreviations used in this paper: AA, ascorbic acid; Cav1, caveolin-1; CT, cholera toxin; CTB, CT binding subunit; DN, dominant-negative; GEEC, GPI-AP–enriched early endosomal compartment; GPI-AP, GPI-anchored protein; LacCer, lactosyl ceramide; MEF, mouse embryonic fibroblast; OA, okadaic acid; PM, plasma membrane; SV40, simian virus 40; Tf, transferrin; TfR, transferrin receptor; WT, wild-type.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents