scholarly journals Myosin driven Actin Filament Sliding is Responsible for Endoplasmic Reticulum and Golgi Movement

2018 ◽  
Author(s):  
Joseph F McKenna ◽  
Stephen E D Webb ◽  
Verena Kriechbaumer ◽  
Chris Hawes
Keyword(s):  
Endoplasmic Reticulum ◽  
Actin Cytoskeleton ◽  
Actin Filament ◽  
Secretory Pathway ◽  
Motor Proteins ◽  
In Planta ◽  
Cell Dynamics ◽  
Myosin Motor ◽  
Golgi Bodies ◽  
Early Secretory Pathway

AbstractThe plant secretory pathway is responsible for the production of the majority of proteins and carbohydrates consumed on the planet. The early secretory pathway is composed of Golgi bodies and the endoplasmic reticulum (ER) and is highly mobile in plants with rapid remodelling of the ER network. The dynamics of the ER and Golgi bodies is driven by the actin cytoskeleton and myosin motor proteins play a key role in this. However, exactly how myosin motor proteins drive remodelling in plants is currently a contentious issue. Here, using a combination of live cell microscopy and over-expression of non-functional myosins we demonstrate that myosin motor proteins drive actin filament sliding and subsequently the dynamics of the secretory pathway.SummaryIn plants, the actin cytoskeleton and myosins are fundamental for normal dynamics of the endomembrane system and cytoplasmic streaming. We demonstrate that this is in part due to myosin driven sliding of actin filaments within a bundle. This generates, at least in part, the motive force required for cell dynamics in planta.

The role of microtubules in transport between the endoplasmic reticulum and Golgi apparatus in mammalian cells.

2005 ◽  
Vol 72 ◽  
pp. 1-13 ◽  
Author(s):  
Krysten J. Palmer ◽  
Peter Watson ◽  
David J. Stephens
Keyword(s):  
Endoplasmic Reticulum ◽  
Mammalian Cells ◽  
Secretory Pathway ◽  
Motor Proteins ◽  
Microtubule Cytoskeleton ◽  
Early Secretory Pathway ◽  
Golgi Transport ◽  
Intracellular Compartments ◽  
Retrograde Traffic

The organization of intracellular compartments and the transfer of components between them are central to the correct functioning of mammalian cells. Proteins and lipids are transferred between compartments by the formation, movement and subsequent specific fusion of transport intermediates. These vesicles and membrane clusters must be coupled to the cytoskeleton and to motor proteins that drive motility. Anterograde ER (endoplasmic reticulum)-to-Golgi transport, and the converse step of retrograde traffic from the Golgi to the ER, are now known to involve coupling of membranes to the microtubule cytoskeleton. Here we shall discuss our current understanding of the mechanisms that link membrane traffic in the early secretory pathway to the microtubule cytoskeleton in mammalian cells. Recent data have also provided molecular detail of functional co-ordination of motor proteins to specify directionality, as well as mechanisms for regulating motor activity by protein phosphorylation.

scholarly journals MIA3/TANGO1 enables efficient secretion by constraining COPII vesicle budding

2021 ◽  
Author(s):  
Janine McCaughey ◽  
Judith M. Mantell ◽  
Chris R. Neal ◽  
Kate Heesom ◽  
David J. Stephens
Keyword(s):  
Endoplasmic Reticulum ◽  
Light Microscopy ◽  
Secretory Pathway ◽  
Genome Engineering ◽  
High Volume ◽  
Vesicle Budding ◽  
Early Secretory Pathway ◽  
Copii Vesicle ◽  
Intermediate Compartment ◽  
Golgi Organization

AbstractComplex machinery is required to drive secretory cargo export from the endoplasmic reticulum. In vertebrates, this includes transport and Golgi organization protein 1 (TANGO1), encoded by the Mia3 gene. Here, using genome engineering of human cells light microscopy, secretion assays, and proteomics, we show loss of Mia3/TANGO1 results in formation of numerous vesicles and a loss of early secretory pathway integrity. This restricts secretion not only of large proteins like procollagens but of all types of secretory cargo. Our data shows that Mia3/TANGO1 constrains the propensity of COPII to form vesicles promoting instead the formation of the ER-Golgi intermediate compartment. Thus, Mia3/TANGO1 facilities the secretion of complex and high volume cargoes from vertebrate cells.

Peroxisomal membrane proteins are properly targeted to peroxisomes in the absence of COPI- and COPII-mediated vesicular transport

2001 ◽  
Vol 114 (11) ◽  
pp. 2199-2204 ◽  
Author(s):  
Tineke Voorn-Brouwer ◽  
Astrid Kragt ◽  
Henk F. Tabak ◽  
Ben Distel
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Secretory Pathway ◽  
Human Fibroblasts ◽  
Vesicle Transport ◽  
Peroxisome Biogenesis ◽  
Peroxisomal Membrane ◽  
Classic Model ◽  
Early Secretory Pathway

The classic model for peroxisome biogenesis states that new peroxisomes arise by the fission of pre-existing ones and that peroxisomal matrix and membrane proteins are recruited directly from the cytosol. Recent studies challenge this model and suggest that some peroxisomal membrane proteins might traffic via the endoplasmic reticulum to peroxisomes. We have studied the trafficking in human fibroblasts of three peroxisomal membrane proteins, Pex2p, Pex3p and Pex16p, all of which have been suggested to transit the endoplasmic reticulum before arriving in peroxisomes. Here, we show that targeting of these peroxisomal membrane proteins is not affected by inhibitors of COPI and COPII that block vesicle transport in the early secretory pathway. Moreover, we have obtained no evidence for the presence of these peroxisomal membrane proteins in compartments other than peroxisomes and demonstrate that COPI and COPII inhibitors do not affect peroxisome morphology or integrity. Together, these data fail to provide any evidence for a role of the endoplasmic reticulum in peroxisome biogenesis.

scholarly journals A New Role for Annexin A11 in the Early Secretory Pathway via Stabilizing Sec31A Protein at the Endoplasmic Reticulum Exit Sites (ERES)

2014 ◽  
Vol 290 (8) ◽  
pp. 4981-4993 ◽  
Author(s):  
Hideki Shibata ◽  
Takashi Kanadome ◽  
Hirofumi Sugiura ◽  
Takeru Yokoyama ◽  
Minami Yamamuro ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Pathway ◽  
Early Secretory Pathway ◽  
Annexin A11

scholarly journals Erv14p Directs a Transmembrane Secretory Protein into COPII-coated Transport Vesicles

2002 ◽  
Vol 13 (3) ◽  
pp. 880-891 ◽  
Author(s):  
Jacqueline Powers ◽  
Charles Barlowe
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Pathway ◽  
Integral Membrane Protein ◽  
Secretory Protein ◽  
Conserved Residues ◽  
Early Secretory Pathway ◽  
Transport Vesicles ◽  
Copii Vesicle ◽  
Copii Vesicles ◽  
Selection Of

Erv14p is a conserved integral membrane protein that traffics in COPII-coated vesicles and localizes to the early secretory pathway in yeast. Deletion of ERV14 causes a defect in polarized growth because Axl2p, a transmembrane secretory protein, accumulates in the endoplasmic reticulum and is not delivered to its site of function on the cell surface. Herein, we show that Erv14p is required for selection of Axl2p into COPII vesicles and for efficient formation of these vesicles. Erv14p binds to subunits of the COPII coat and binding depends on conserved residues in a cytoplasmically exposed loop domain of Erv14p. When mutations are introduced into this loop, an Erv14p-Axl2p complex accumulates in the endoplasmic reticulum, suggesting that Erv14p links Axl2p to the COPII coat. Based on these results and further genetic experiments, we propose Erv14p coordinates COPII vesicle formation with incorporation of specific secretory cargo.

scholarly journals A role for endoplasmic reticulum exit sites in foot-and-mouth disease virus infection

2013 ◽  
Vol 94 (12) ◽  
pp. 2636-2646 ◽  
Author(s):  
Rebecca Midgley ◽  
Katy Moffat ◽  
Stephen Berryman ◽  
Philippa Hawes ◽  
Jennifer Simpson ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Disease Virus ◽  
Secretory Pathway ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Rab Proteins ◽  
Fmdv Infection ◽  
Early Secretory Pathway ◽  
Mouth Disease Virus ◽  
Foot And Mouth

Picornaviruses replicate their genomes in association with cellular membranes. While enteroviruses are believed to utilize membranes of the early secretory pathway, the origin of the membranes used by foot-and-mouth disease virus (FMDV) for replication are unknown. Secretory-vesicle traffic through the early secretory pathway is mediated by the sequential acquisition of two distinct membrane coat complexes, COPII and COPI, and requires the coordinated actions of Sar1, Arf1 and Rab proteins. Sar1 is essential for generating COPII vesicles at endoplasmic reticulum (ER) exit sites (ERESs), while Arf1 and Rab1 are required for subsequent vesicle transport by COPI vesicles. In the present study, we have provided evidence that FMDV requires pre-Golgi membranes of the early secretory pathway for infection. Small interfering RNA depletion of Sar1 or expression of a dominant-negative (DN) mutant of Sar1a inhibited FMDV infection. In contrast, a dominant-active mutant of Sar1a, which allowed COPII vesicle formation but inhibited the secretory pathway by stabilizing COPII coats, caused major disruption to the ER–Golgi intermediate compartment (ERGIC) but did not inhibit infection. Treatment of cells with brefeldin A, or expression of DN mutants of Arf1 and Rab1a, disrupted the Golgi and enhanced FMDV infection. These results show that reagents that block the early secretory pathway at ERESs have an inhibitory effect on FMDV infection, while reagents that block the early secretory pathway immediately after ER exit but before the ERGIC and Golgi make infection more favourable. Together, these observations argue for a role for Sar1 in FMDV infection and that initial virus replication takes place on membranes that are formed at ERESs.

scholarly journals Organizational Diversity among Distinct Glycoprotein Endoplasmic Reticulum-associated Degradation Programs

2002 ◽  
Vol 13 (8) ◽  
pp. 2639-2650 ◽  
Author(s):  
Christopher M. Cabral ◽  
Yan Liu ◽  
Kelley W. Moremen ◽  
Richard N. Sifers
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Pathway ◽  
Degradation Process ◽  
Secretory Protein ◽  
Human Embryonic Kidney ◽  
Apparent Lack ◽  
Human Embryonic Kidney Cells ◽  
Early Secretory Pathway ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Pathway Function

Protein folding and quality control in the early secretory pathway function as posttranslational checkpoints in eukaryote gene expression. Herein, an aberrant form of the hepatic secretory protein α1-antitrypsin was stably expressed in a human embryonic kidney cell line to elucidate the mechanisms by which glycoprotein endoplasmic reticulum-associated degradation (GERAD) is administered in cells from higher eukaryotes. After biosynthesis, genetic variant PI Z underwent alternative phases of secretion and degradation, the latter of which was mediated by the proteasome. Degradation required release from calnexin- and asparagine-linked oligosaccharide modification by endoplasmic reticulum mannosidase I, the latter of which occurred as PI Z was bound to the molecular chaperone grp78/BiP. That a distinct GERAD program operates in human embryonic kidney cells was supported by the extent of PI Z secretion, apparent lack of polymerization, inability of calnexin to participate in the degradation process, and sequestration of the glycoprotein folding sensor UDP-glucose:glycoprotein glucosyltransferase in the Golgi complex. Because UDP-glucose:glycoprotein glucosyltransferase sustains calnexin binding, its altered distribution is consistent with a GERAD program that hinders the reentry of substrates into the calnexin cycle, allowing grp78/BiP to partner with a lectin, other than calnexin, in the recognition of a two-component GERAD signal to facilitate substrate recruitment. How the processing of a mutant protein, rather than the mutation itself, can contribute to disease pathogenesis, is discussed.

scholarly journals HtrA2 Regulates β-Amyloid Precursor Protein (APP) Metabolism through Endoplasmic Reticulum-associated Degradation

2007 ◽  
Vol 282 (38) ◽  
pp. 28285-28295 ◽  
Author(s):  
Henri J. Huttunen ◽  
Suzanne Y. Guénette ◽  
Camilla Peach ◽  
Christopher Greco ◽  
Weiming Xia ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Pathway ◽  
Proteasome Inhibition ◽  
Precursor Protein ◽  
Amyloid Peptide ◽  
Early Secretory Pathway ◽  
App Metabolism ◽  
Microsomal Membranes ◽  
Β Amyloid

Alzheimer disease-associated β-amyloid peptide is generated from its precursor protein APP. By using the yeast two-hybrid assay, here we identified HtrA2/Omi, a stress-responsive chaperone-protease as a protein binding to the N-terminal cysteinerich region of APP. HtrA2 coimmunoprecipitates exclusively with immature APP from cell lysates as well as mouse brain extracts and degrades APP in vitro. A subpopulation of HtrA2 localizes to the cytosolic side of the endoplasmic reticulum (ER) membrane where it contributes to ER-associated degradation of APP together with the proteasome. Inhibition of the proteasome results in accumulation of retrotranslocated forms of APP and increased association of APP with HtrA2 and Derlin-1 in microsomal membranes. In cells lacking HtrA2, APP holoprotein is stabilized and accumulates in the early secretory pathway correlating with elevated levels of APP C-terminal fragments and increased Aβ secretion. Inhibition of ER-associated degradation (either HtrA2 or proteasome) promotes binding of APP to the COPII protein Sec23 suggesting enhanced trafficking of APP out of the ER. Based on these results we suggest a novel function for HtrA2 as a regulator of APP metabolism through ER-associated degradation.

scholarly journals KMS1 and KMS2, two plant endoplasmic reticulum proteins involved in the early secretory pathway

2011 ◽  
Vol 66 (4) ◽  
pp. 613-628 ◽  
Author(s):  
Pengwei Wang ◽  
Eric Hummel ◽  
Anne Osterrieder ◽  
Andreas J. Meyer ◽  
Lorenzo Frigerio ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Pathway ◽  
Early Secretory Pathway ◽  
Endoplasmic Reticulum Proteins
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