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

This Article Full Text Full Text (PDF, 1240K) PPT slides of all figures Supplemental Material Index Alert me when this article is cited Citation Map Services Email this article Similar articles in this journal Similar articles in PubMed Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Aridor, M. Articles by Balch, W. E. Search for Related Content PubMed PubMed Citation Articles by Aridor, M. Articles by Balch, W. E. Pubmed/NCBI databases Protein Social Bookmarking                            What's this?

© The Rockefeller University Press, 0021-9525/2001//213 $5.00
The Journal of Cell Biology, Volume 152, Number 1, , 2001 213-230

The Sar1 Gtpase Coordinates Biosynthetic Cargo Selection with Endoplasmic Reticulum Export Site Assembly

^a Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California 92037
^b The Institute of Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, California 92037
^c The Harold L. Dorris Neurological Research Center, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
^d Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
Department of Cell and Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037.858-784-9126858-784-2310

webalch{at}scripps.edu

Cargo selection and export from the endoplasmic reticulum is mediated by the COPII coat machinery that includes the small GTPase Sar1 and the Sec23/24 and Sec13/31 complexes. We have analyzed the sequential events regulated by purified Sar1 and COPII coat complexes during synchronized export of cargo from the ER in vitro. We find that activation of Sar1 alone, in the absence of other cytosolic components, leads to the formation of ER-derived tubular domains that resemble ER transitional elements that initiate cargo selection. These Sar1-generated tubular domains were shown to be transient, functional intermediates in ER to Golgi transport in vitro. By following cargo export in live cells, we show that ER export in vivo is also characterized by the formation of dynamic tubular structures. Our results demonstrate an unanticipated and novel role for Sar1 in linking cargo selection with ER morphogenesis through the generation of transitional tubular ER export sites.

Key Words: Sar1 • COPII • endoplasmic reticulum • vesicle • cargo export

© 2001 The Rockefeller University Press

Dr. Aridor's current address is Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, 3500 Terrace Street, BST South 362, Pittsburgh, PA 15251.

Abbreviations used in this paper: BIP, immunoglobulin binding protein; DIC, differential interference contrast; DTSSP, 3'-dithiobissulfosuccimidylpropionate; GFP, green fluorescent protein; GST, glutathione-S-transferase; Man II, 1,2-mannosidase II; MT, microtubule; NRK, normal rat kidney; VTC, vesicular tubular cluster.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Facebook

Reddit

Technorati

Twitter

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