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Review
. 2011 Dec 9;147(6):1226-31.
doi: 10.1016/j.cell.2011.11.022.

Weaving the web of ER tubules

Junjie Hu  1 , William A Prinz, Tom A Rapoport
Affiliations
Review

Weaving the web of ER tubules

Junjie Hu et al. Cell. .

Erratum in

  • Cell. 2012 Feb 17;148(4):832

Abstract

How is the characteristic shape of an organelle generated? Recent work has provided insight into how the tubular network of the endoplasmic reticulum (ER) is formed. The tubules themselves are shaped by the reticulons and DP1/Yop1p, whereas their fusion into a network is brought about by membrane-bound GTPases that include the atlastins, Sey1p, and RHD3.

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Figures

Figure 1
Figure 1. The Reticulons and DP1/Yop1p Shape ER Tubules
The cut-away view shows the double hairpin structure of the proteins proposed to form a wedge. Several of these molecules would form an arc-like structure around the tubule (indicated by yellow strips).
Figure 2
Figure 2. The Fusion Reaction Mediated by the Atlastins
The mechanism of membrane tethering and fusion is based on two crystal structures (state 1 [PDB 3QOF] and state 5 [3QNU]) and biochemical experiments. The atlastin (ATL) molecule in one membrane is colored with its GTPase domain in green and the helix bundle in yellow. The ATL molecule in the apposing membrane is colored with its GTPase domain in purple and the helix bundle in cyan. Upon GTP binding, the two ATL molecules dimerize and tether the membranes. GTP hydrolysis then causes conformational changes that pull the membranes together. Finally, GDP is released to reset the fusion machinery.
See this image and copyright information in PMC

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