Direct observation of molecular arrays in the organized smooth endoplasmic reticulum

<p>Abstract</p> <p>Background</p> <p>Tubules and sheets of endoplasmic reticulum perform different functions and undergo inter-conversion during different stages of the cell cycle. Tubules are stabilized by curvature inducing resident proteins, but little is known about...

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Main Authors: Korkhov Vladimir M, Zuber Benoît
Format: Article
Language:English
Published: BMC 2009-08-01
Series:BMC Cell Biology
Online Access:http://www.biomedcentral.com/1471-2121/10/59
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author Korkhov Vladimir M
Zuber Benoît
author_facet Korkhov Vladimir M
Zuber Benoît
author_sort Korkhov Vladimir M
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Tubules and sheets of endoplasmic reticulum perform different functions and undergo inter-conversion during different stages of the cell cycle. Tubules are stabilized by curvature inducing resident proteins, but little is known about the mechanisms of endoplasmic reticulum sheet stabilization. Tethering of endoplasmic reticulum membranes to the cytoskeleton or to each other has been proposed as a plausible way of sheet stabilization.</p> <p>Results</p> <p>Here, using fluorescence microscopy we show that the previously proposed mechanisms, such as membrane tethering via GFP-dimerization or coiled coil protein aggregation do not explain the formation of the calnexin-induced organized smooth endoplasmic reticulum membrane stacks. We also show that the LINC complex proteins known to serve a tethering function in the nuclear envelope are excluded from endoplasmic reticulum stacks. Finally, using cryo-electron microscopy of vitreous sections methodology that preserves cellular architecture in a hydrated, native-like state, we show that the sheet stacks are highly regular and may contain ordered arrays of macromolecular complexes. Some of these complexes decorate the cytosolic surface of the membranes, whereas others appear to span the width of the cytosolic or luminal space between the stacked sheets.</p> <p>Conclusion</p> <p>Our results provide evidence in favour of the hypothesis of endoplasmic reticulum sheet stabilization by intermembrane tethering.</p>
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spelling doaj.art-a67467cffd614268a5fd9020fcb06a0b2022-12-22T02:59:42ZengBMCBMC Cell Biology1471-21212009-08-011015910.1186/1471-2121-10-59Direct observation of molecular arrays in the organized smooth endoplasmic reticulumKorkhov Vladimir MZuber Benoît<p>Abstract</p> <p>Background</p> <p>Tubules and sheets of endoplasmic reticulum perform different functions and undergo inter-conversion during different stages of the cell cycle. Tubules are stabilized by curvature inducing resident proteins, but little is known about the mechanisms of endoplasmic reticulum sheet stabilization. Tethering of endoplasmic reticulum membranes to the cytoskeleton or to each other has been proposed as a plausible way of sheet stabilization.</p> <p>Results</p> <p>Here, using fluorescence microscopy we show that the previously proposed mechanisms, such as membrane tethering via GFP-dimerization or coiled coil protein aggregation do not explain the formation of the calnexin-induced organized smooth endoplasmic reticulum membrane stacks. We also show that the LINC complex proteins known to serve a tethering function in the nuclear envelope are excluded from endoplasmic reticulum stacks. Finally, using cryo-electron microscopy of vitreous sections methodology that preserves cellular architecture in a hydrated, native-like state, we show that the sheet stacks are highly regular and may contain ordered arrays of macromolecular complexes. Some of these complexes decorate the cytosolic surface of the membranes, whereas others appear to span the width of the cytosolic or luminal space between the stacked sheets.</p> <p>Conclusion</p> <p>Our results provide evidence in favour of the hypothesis of endoplasmic reticulum sheet stabilization by intermembrane tethering.</p>http://www.biomedcentral.com/1471-2121/10/59
spellingShingle Korkhov Vladimir M
Zuber Benoît
Direct observation of molecular arrays in the organized smooth endoplasmic reticulum
BMC Cell Biology
title Direct observation of molecular arrays in the organized smooth endoplasmic reticulum
title_full Direct observation of molecular arrays in the organized smooth endoplasmic reticulum
title_fullStr Direct observation of molecular arrays in the organized smooth endoplasmic reticulum
title_full_unstemmed Direct observation of molecular arrays in the organized smooth endoplasmic reticulum
title_short Direct observation of molecular arrays in the organized smooth endoplasmic reticulum
title_sort direct observation of molecular arrays in the organized smooth endoplasmic reticulum
url http://www.biomedcentral.com/1471-2121/10/59
work_keys_str_mv AT korkhovvladimirm directobservationofmoleculararraysintheorganizedsmoothendoplasmicreticulum
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