scholarly journals Molecular mechanisms of contractile-ring constriction and membrane trafficking in cytokinesis

2018 ◽  
Vol 10 (6) ◽  
pp. 1649-1666 ◽  
Author(s):  
Kenneth S. Gerien ◽  
Jian-Qiu Wu
Keyword(s):  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Contractile Ring ◽  
Ring Constriction

scholarly journals Rab1 interacts with GOLPH3 and controls Golgi structure and contractile ring constriction during cytokinesis in Drosophila melanogaster

Open Biology ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 160257 ◽  
Author(s):  
Stefano Sechi ◽  
Anna Frappaolo ◽  
Roberta Fraschini ◽  
Luisa Capalbo ◽  
Marco Gottardo ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Super Resolution ◽  
Cleavage Furrow ◽  
Contractile Ring ◽  
Cog Complex ◽  
Dividing Cells ◽  
Ring Constriction ◽  
Phosphatidylinositol 4

Cytokinesis requires a tight coordination between actomyosin ring constriction and new membrane addition along the ingressing cleavage furrow. However, the molecular mechanisms underlying vesicle trafficking to the equatorial site and how this process is coupled with the dynamics of the contractile apparatus are poorly defined. Here we provide evidence for the requirement of Rab1 during cleavage furrow ingression in cytokinesis. We demonstrate that the gene omelette ( omt ) encodes the Drosophila orthologue of human Rab1 and is required for successful cytokinesis in both mitotic and meiotic dividing cells of Drosophila melanogaster . We show that Rab1 protein colocalizes with the conserved oligomeric Golgi (COG) complex Cog7 subunit and the phosphatidylinositol 4-phosphate effector GOLPH3 at the Golgi stacks. Analysis by transmission electron microscopy and 3D-SIM super-resolution microscopy reveals loss of normal Golgi architecture in omt mutant spermatocytes indicating a role for Rab1 in Golgi formation. In dividing cells, Rab1 enables stabilization and contraction of actomyosin rings. We further demonstrate that GTP-bound Rab1 directly interacts with GOLPH3 and controls its localization at the Golgi and at the cleavage site . We propose that Rab1, by associating with GOLPH3, controls membrane trafficking and contractile ring constriction during cytokinesis.

The roles of the oncoprotein GOLPH3 in contractile ring assembly and membrane trafficking during cytokinesis

2015 ◽  
Vol 43 (1) ◽  
pp. 117-121 ◽  
Author(s):  
Stefano Sechi ◽  
Anna Frappaolo ◽  
Giorgio Belloni ◽  
Maria Grazia Giansanti
Keyword(s):  
Membrane Trafficking ◽  
Cancer Biology ◽  
Molecular Mechanisms ◽  
Cleavage Furrow ◽  
The Novel ◽  
Ring Assembly ◽  
Dividing Cells ◽  
Ring Constriction ◽  
Phosphatidylinositol 4 ◽  
Cytoskeleton Dynamics

Cytokinesis is an intricate process that requires an intimate interplay between actomyosin ring constriction and plasma membrane remodelling at the cleavage furrow. However, the molecular mechanisms involved in coupling the cytoskeleton dynamics with vesicle trafficking during cytokinesis are poorly understood. The highly conserved Golgi phosphoprotein 3 (GOLPH3), functions as a phosphatidylinositol 4-phosphate (PI4P) effector at the Golgi. Recent studies have suggested that GOLPH3 is up-regulated in several cancers and is associated with poor prognosis and more aggressive tumours. In Drosophila melanogaster, GOLPH3 localizes at the cleavage furrow of dividing cells, is required for successful cytokinesis and acts as a key molecule in coupling phosphoinositide (PI) signalling with actomyosin ring dynamics. Because cytokinesis failures have been linked with pre-malignant disease and cancer, the novel connection between GOLPH3 and cytokinesis imposes new fields of investigation in cancer biology and therapy.

scholarly journals Nine unanswered questions about cytokinesis

2017 ◽  
Vol 216 (10) ◽  
pp. 3007-3016 ◽  
Author(s):  
Thomas D. Pollard
Keyword(s):  
Plasma Membrane ◽  
Cell Membranes ◽  
Daughter Cell ◽  
Molecular Mechanisms ◽  
Model Systems ◽  
Divergent Evolution ◽  
Contractile Ring ◽  
Ring Constriction ◽  
Evolution Understanding ◽  
In Cells

Experiments on model systems have revealed that cytokinesis in cells with contractile rings (amoebas, fungi, and animals) depends on shared molecular mechanisms in spite of some differences that emerged during a billion years of divergent evolution. Understanding these fundamental mechanisms depends on identifying the participating proteins and characterizing the mechanisms that position the furrow, assemble the contractile ring, anchor the ring to the plasma membrane, trigger ring constriction, produce force to form a furrow, disassemble the ring, expand the plasma membrane in the furrow, and separate the daughter cell membranes. This review reveals that fascinating questions remain about each step.

scholarly journals Divergence of a genomic island leads to the evolution of melanization in a halophyte root fungus

2021 ◽  
Author(s):  
Zhilin Yuan ◽  
Irina S. Druzhinina ◽  
John G. Gibbons ◽  
Zhenhui Zhong ◽  
Yves Van de Peer ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Genomic Island ◽  
Population Genomics ◽  
Growth Yield ◽  
Fixation Index ◽  
Nucleotide Polymorphisms ◽  
Evolutionary Mechanisms ◽  
Melanin Biosynthesis ◽  
Two Populations

AbstractUnderstanding how organisms adapt to extreme living conditions is central to evolutionary biology. Dark septate endophytes (DSEs) constitute an important component of the root mycobiome and they are often able to alleviate host abiotic stresses. Here, we investigated the molecular mechanisms underlying the beneficial association between the DSE Laburnicola rhizohalophila and its host, the native halophyte Suaeda salsa, using population genomics. Based on genome-wide Fst (pairwise fixation index) and Vst analyses, which compared the variance in allele frequencies of single-nucleotide polymorphisms (SNPs) and copy number variants (CNVs), respectively, we found a high level of genetic differentiation between two populations. CNV patterns revealed population-specific expansions and contractions. Interestingly, we identified a ~20 kbp genomic island of high divergence with a strong sign of positive selection. This region contains a melanin-biosynthetic polyketide synthase gene cluster linked to six additional genes likely involved in biosynthesis, membrane trafficking, regulation, and localization of melanin. Differences in growth yield and melanin biosynthesis between the two populations grown under 2% NaCl stress suggested that this genomic island contributes to the observed differences in melanin accumulation. Our findings provide a better understanding of the genetic and evolutionary mechanisms underlying the adaptation to saline conditions of the L. rhizohalophila–S. salsa symbiosis.

scholarly journals Genetic analysis of amyotrophic lateral sclerosis identifies contributing pathways and cell types

2021 ◽  
Vol 7 (3) ◽  
pp. eabd9036
Author(s):  
Sara Saez-Atienzar ◽  
Sara Bandres-Ciga ◽  
Rebekah G. Langston ◽  
Jonggeol J. Kim ◽  
Shing Wan Choi ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Polygenic Risk Score ◽  
Genome Wide ◽  
Genome Wide Data ◽  
Data Driven Approach ◽  
Single Nucleus ◽  
Lateral Sclerosis

Despite the considerable progress in unraveling the genetic causes of amyotrophic lateral sclerosis (ALS), we do not fully understand the molecular mechanisms underlying the disease. We analyzed genome-wide data involving 78,500 individuals using a polygenic risk score approach to identify the biological pathways and cell types involved in ALS. This data-driven approach identified multiple aspects of the biology underlying the disease that resolved into broader themes, namely, neuron projection morphogenesis, membrane trafficking, and signal transduction mediated by ribonucleotides. We also found that genomic risk in ALS maps consistently to GABAergic interneurons and oligodendrocytes, as confirmed in human single-nucleus RNA-seq data. Using two-sample Mendelian randomization, we nominated six differentially expressed genes (ATG16L2, ACSL5, MAP1LC3A, MAPKAPK3, PLXNB2, and SCFD1) within the significant pathways as relevant to ALS. We conclude that the disparate genetic etiologies of this fatal neurological disease converge on a smaller number of final common pathways and cell types.

scholarly journals CYK-4 regulates Rac, but not Rho, during cytokinesis

2017 ◽  
Vol 28 (9) ◽  
pp. 1258-1270 ◽  
Author(s):  
Yelena Zhuravlev ◽  
Sophia M. Hirsch ◽  
Shawn N. Jordan ◽  
Julien Dumont ◽  
Mimi Shirasu-Hiza ◽  
...  
Keyword(s):  
Alternative Model ◽  
Single Cell Analysis ◽  
Myosin Ii ◽  
Small Gtpases ◽  
Nucleotide Exchange ◽  
Filamentous Actin ◽  
Contractile Ring ◽  
Division Plane ◽  
Ring Constriction

Cytokinesis is driven by constriction of an actomyosin contractile ring that is controlled by Rho-family small GTPases. Rho, activated by the guanine-nucleotide exchange factor ECT-2, is upstream of both myosin-II activation and diaphanous formin-mediated filamentous actin (f-actin) assembly, which drive ring constriction. The role for Rac and its regulators is more controversial, but, based on the finding that Rac inactivation can rescue cytokinesis failure when the GTPase-activating protein (GAP) CYK-4 is disrupted, Rac activity was proposed to be inhibitory to contractile ring constriction and thus specifically inactivated by CYK-4 at the division plane. An alternative model proposes that Rac inactivation generally rescues cytokinesis failure by reducing cortical tension, thus making it easier for the cell to divide when ring constriction is compromised. In this alternative model, CYK-4 was instead proposed to activate Rho by binding ECT-2. Using a combination of time-lapse in vivo single-cell analysis and Caenorhabditis elegans genetics, our evidence does not support this alternative model. First, we found that Rac disruption does not generally rescue cytokinesis failure: inhibition of Rac specifically rescues cytokinesis failure due to disruption of CYK-4 or ECT-2 but does not rescue cytokinesis failure due to disruption of two other contractile ring components, the Rho effectors diaphanous formin and myosin-II. Second, if CYK-4 regulates cytokinesis through Rho rather than Rac, then CYK-4 inhibition should decrease levels of downstream targets of Rho. Inconsistent with this, we found no change in the levels of f-actin or myosin-II at the division plane when CYK-4 GAP activity was reduced, suggesting that CYK-4 is not upstream of ECT-2/Rho activation. Instead, we found that the rescue of cytokinesis in CYK-4 mutants by Rac inactivation was Cdc42 dependent. Together our data suggest that CYK-4 GAP activity opposes Rac (and perhaps Cdc42) during cytokinesis.

Retrograde trafficking of both Golgi complex and TGN markers to the ER induced by nordihydroguaiaretic acid and cyclofenil diphenol

1998 ◽  
Vol 111 (7) ◽  
pp. 951-965 ◽  
Author(s):  
D. Drecktrah ◽  
P. de Figueiredo ◽  
R.M. Mason ◽  
W.J. Brown
Keyword(s):  
Golgi Complex ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Nordihydroguaiaretic Acid ◽  
Retrograde Transport ◽  
Lipoxygenase Inhibitor ◽  
Golgi Stack ◽  
Golgi Network ◽  
In Vivo Effects

Previous studies have shown that the Golgi stack and the trans-Golgi network (TGN) may play a role in capturing escaped resident endoplasmic reticulum (ER) proteins, and directing their retrograde transport back to that organelle. Whether this retrograde movement represents a highly specific or more generalized membrane trafficking pathway is unclear. To better understand both the retrograde and anterograde trafficking pathways of the secretory apparatus, we examined more closely the in vivo effects of two structurally unrelated compounds, the potent lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA), and the non-steroidal estrogen cyclofenil diphenol (CFD), both of which are known to inhibit secretion. In the presence of these compounds, transport of vesicular stomatitis virus G membrane glycoprotein from the ER to the Golgi complex, and from the TGN to the cell surface, was inhibited potently and rapidly. Surprisingly, we found that NDGA and CFD stimulated the rapid, but not concomitant, retrograde movement of both Golgi stack and TGN membrane proteins back to the ER until both organelles were morphologically absent from cells. Both NDGA- and CFD-stimulated TGN and Golgi retrograde membrane trafficking were inhibited by microtubule depolymerizing agents and energy poisons. Removal of NDGA and CFD resulted in the complete, but not concomitant, reformation of both Golgi stacks and their closely associated TGN compartments. These studies suggest that NDGA and CFD unmask a generalized bulk recycling pathway to the ER for both Golgi and TGN membranes and, further, that NDGA and CFD are useful for investigating the molecular mechanisms that control the formation and maintenance of both the Golgi stack proper and the TGN.

Role of membrane trafficking in plasma membrane solute transport

1994 ◽  
Vol 267 (1) ◽  
pp. C1-C24 ◽  
Author(s):  
N. A. Bradbury ◽  
R. J. Bridges
Keyword(s):  
Plasma Membrane ◽  
Solute Transport ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Glucose Transporter ◽  
Water Channel ◽  
Transport Proteins ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Regulated Trafficking

Cells can rapidly and reversibly alter solute transport rates by changing the kinetics of transport proteins resident within the plasma membrane. Most notably, this can be brought about by reversible phosphorylation of the transporter. An additional mechanism for acute regulation of plasma membrane transport rates is by the regulated exocytic insertion of transport proteins from intracellular vesicles into the plasma membrane and their subsequent regulated endocytic retrieval. Over the past few years, the number of transporters undergoing this regulated trafficking has increased dramatically, such that what was once an interesting translocation of a few transporters has now become a widespread modality for regulating plasma membrane solute permeabilities. The aim of this article is to review the models proposed for the regulated trafficking of transport proteins and what lines of evidence should be obtained to document regulated exocytic insertion and endocytic retrieval of transport proteins. We highlight four transporters, the insulin-responsive glucose transporter, the antidiuretic hormone-responsive water channel, the urinary bladder H(+)-ATPase, and the cystic fibrosis transmembrane conductance regulator Cl- channel, and discuss the various approaches taken to document their regulated trafficking. Finally, we discuss areas of uncertainty that remain to be investigated concerning the molecular mechanisms involved in regulating the trafficking of proteins.

scholarly journals Polar relaxation by dynein-mediated removal of cortical myosin II

2020 ◽  
Vol 219 (8) ◽  
Author(s):  
Bernardo Chapa-y-Lazo ◽  
Motonari Hamanaka ◽  
Alexander Wray ◽  
Mohan K. Balasubramanian ◽  
Masanori Mishima
Keyword(s):  
Recent Work ◽  
Molecular Mechanism ◽  
Molecular Mechanisms ◽  
Myosin Ii ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Contractile Ring ◽  
C Elegans ◽  
Polar Cell

Nearly six decades ago, Lewis Wolpert proposed the relaxation of the polar cell cortex by the radial arrays of astral microtubules as a mechanism for cleavage furrow induction. While this mechanism has remained controversial, recent work has provided evidence for polar relaxation by astral microtubules, although its molecular mechanisms remain elusive. Here, using C. elegans embryos, we show that polar relaxation is achieved through dynein-mediated removal of myosin II from the polar cortexes. Mutants that position centrosomes closer to the polar cortex accelerated furrow induction, whereas suppression of dynein activity delayed furrowing. We show that dynein-mediated removal of myosin II from the polar cortexes triggers a bidirectional cortical flow toward the cell equator, which induces the assembly of the actomyosin contractile ring. These results provide a molecular mechanism for the aster-dependent polar relaxation, which works in parallel with equatorial stimulation to promote robust cytokinesis.

scholarly journals Mitochondrial morphology and activity regulate furrow ingression and contractile ring dynamics in Drosophila cellularization

2020 ◽  
Vol 31 (21) ◽  
pp. 2331-2347
Author(s):  
Sayali Chowdhary ◽  
Somya Madan ◽  
Darshika Tomer ◽  
Manos Mavrakis ◽  
Richa Rikhy
Keyword(s):  
Mitochondrial Fission ◽  
Cell Formation ◽  
Mitochondrial Morphology ◽  
Contractile Ring ◽  
Drosophila Embryogenesis ◽  
Ring Dynamics ◽  
Mitochondrial Distribution ◽  
Ring Constriction

Drp1-regulated mitochondrial fission is essential for mitochondrial distribution across the cell in cellularization during Drosophila embryogenesis. Loss of mitochondrial fission in Drp1 mutant embryos leads to defects in morphogenetic events of cell formation and contractile ring constriction in cellularization.

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