scholarly journals Correlative AFM and fluorescence imaging demonstrate nanoscale membrane remodeling and ring-like and tubular structure formation by septins

Nanoscale ◽  
2021 ◽  
Author(s):  
Anthony Vial ◽  
Cyntia Taveneau ◽  
Luca Costa ◽  
brieuc chauvin ◽  
hussein nasrallah ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Division ◽  
Structure Formation ◽  
Fluorescence Imaging ◽  
Tubular Structure ◽  
Membrane Remodeling

Septins are ubiquitous cytoskeletal filaments that interact with the inner plasma membrane and are essential for cell division in eukaryotes. In cellular contexts, septins are often localized at micrometric gaussian...

scholarly journals New interactions of invadopodia scaffold protein TKS5 with proteins that take part in actin cytoskeleton reorganization, endo-/exocytosis and membrane remodeling

2019 ◽  
Vol 16 (2) ◽  
pp. 183-189
Author(s):  
Y. M. Nemesh ◽  
S. V. Kropyvko
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Scaffold Protein ◽  
Scaffold Proteins ◽  
Membrane Remodeling ◽  
Sh3 Domains ◽  
Protein Protein Interaction ◽  
Cytoskeleton Reorganization ◽  
New Interactions ◽  
Cytoskeleton Rearrangement

Aim. TKS5 is a key scaffold protein of invadopodia. In its absence, the cells completely lose the ability to form invadopodia. This fact makes TKS5 a potential target for cancer cure and one of the central proteins in the investigation of cancer cell invasion. Additionally, the question remains about the function of TKS5 in normal cells. Therefore, in order to extend knowledge about TKS5 role in healthy and invasive cells, we tested the TKS5 interaction with the proteins involved in signal transduction: PLCγ1, SRC, CRK, CSK; the proteins involved in plasma membrane remodeling: AMPH1, BIN1, CIN85, ITSN1, ITSN2; the protein involved in the actin cytoskeleton rearrangement: CTTN. Methods. We used the GST Pull-down assay to identify the protein-protein interaction. Results. We revealed that TKS5 SH3 domains interact with CIN85. There were identified TKS5 interactions with SH3 domains of CTTN, ITSN1, ITSN2, AMPH1 and BIN1. Conclusions. TKS5 interacts with CIN85, CTTN, ITSN1, ITSN2, AMPH1 and BIN1, which take part in membrane remodeling, endo-/exocytosis and actin cytoskeleton rearrangement. Keywords: TKS5, scaffold proteins, actin cytoskeleton, plasma membrane.

Ordered Structure Formation of Bacteriorhodopsin-hDHFR in a Plasma Membrane

Langmuir ◽  
1999 ◽  
Vol 15 (1) ◽  
pp. 214-220 ◽  
Author(s):  
S. Nomura ◽  
N. Kajimura ◽  
K. Matoba ◽  
T. Miyata ◽  
R. Ortenberg ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Structure Formation ◽  
Ordered Structure

Abstract 434: A Novel 5-Step Model for the Mechanism of ABCA1-Mediated Nascent HDL Biogenesis

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Shuhui Wang ◽  
Gregory Brubaker ◽  
Kailash Gulshan ◽  
Jonathan D Smith
Keyword(s):  
Plasma Membrane ◽  
Membrane Lipids ◽  
Sodium Taurocholate ◽  
Hek293 Cells ◽  
Membrane Remodeling ◽  
Fluorescent Indicators ◽  
Step Model ◽  
Partial Unfolding ◽  
Cell Membrane Protein ◽  
Partially Unfolded

Objective— Lipid-poor apoA-I acts as an acceptor for cell cholesterol and phospholipids via the cell membrane protein ABCA1, generating nascent HDL. However, the mechanism of this process is not understood at the molecular level. Methods and Results— We propose a novel five-step model of nascent HDL biogenesis: ABCA1 remodeling of the plasma membrane lipids exposing phosphatidylserine and apoA-I binding to ABCA1 are the first two independent steps; third, ABCA1 facilitates apoA-I partial unfolding; forth, partially unfolded apoA-I inserts into the modified plasma membrane resulting in apoA-I lipidation; and fifth, nascent HDL is released from the cell. We created fluorescent apoA-I indicators that can monitor apoA-I unfolding and lipidation states. In cell free assays of reconstituted HDL (rHDL) generation from apoAI and DMPC liposomes, the fluorescent indicators demonstrated apoA-I unfolding and lipidation concurrent with rHDL formation. Next, HEK293 cells were stably transfected with different ABCA1 vectors encoding wild type (WT) and W590S and C1477R Tangier disease mutation isoforms. WT ABCA1 mediated cholesterol efflux to apoA-I (requires all steps) and sodium taurocholate (NaTC, requires only the membrane remodeling step,). Although neither mutant could efflux cholesterol efficiently to apoA-I, they were blocked at different steps. The W590S mutant bound apoAI but could not efflux cholesterol to NaTC, thus it was blocked at the membrane remodeling step. However, the C1477R mutant could not bind apoAI but could efflux cholesterol to NaTC, thus its activity was blocked at the apoAI binding step. When the lipidation indicator apoA-I was incubated with stably transfected HEK cells, we observed cell associated lipidated apoA-I in cells expressing WT ABCA1, but mostly unlipidated apoA-I was associated with the cells expressing W590S ABCA1. Conclusion— Our results support a novel five-step model for nascent HDL biogenesis: 1, 2) ABCA1 remodeling of the plasma membrane and apoA-I binding to ABCA1, which facilitate 3) apoA-I partial unfolding and 4) and lipidation by the remodeled membrane, followed by 5) the release of nascent HDL.

scholarly journals The proteasome controls ESCRT-III–mediated cell division in an archaeon

Science ◽  
2020 ◽  
Vol 369 (6504) ◽  
pp. eaaz2532 ◽  
Author(s):  
Gabriel Tarrason Risa ◽  
Fredrik Hurtig ◽  
Sian Bray ◽  
Anne E. Hafner ◽  
Lena Harker-Kirschneck ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Replication ◽  
Division Ring ◽  
Cell Cycle Control ◽  
Sulfolobus Acidocaldarius ◽  
Cyclin Dependent Kinase ◽  
Membrane Remodeling

Sulfolobus acidocaldarius is the closest experimentally tractable archaeal relative of eukaryotes and, despite lacking obvious cyclin-dependent kinase and cyclin homologs, has an ordered eukaryote-like cell cycle with distinct phases of DNA replication and division. Here, in exploring the mechanism of cell division in S. acidocaldarius, we identify a role for the archaeal proteasome in regulating the transition from the end of one cell cycle to the beginning of the next. Further, we identify the archaeal ESCRT-III homolog, CdvB, as a key target of the proteasome and show that its degradation triggers division by allowing constriction of the CdvB1:CdvB2 ESCRT-III division ring. These findings offer a minimal mechanism for ESCRT-III–mediated membrane remodeling and point to a conserved role for the proteasome in eukaryotic and archaeal cell cycle control.

scholarly journals Transcriptome Analysis of Sorbic Acid-Stressed Bacillus subtilis Reveals a Nutrient Limitation Response and Indicates Plasma Membrane Remodeling

2007 ◽  
Vol 190 (5) ◽  
pp. 1751-1761 ◽  
Author(s):  
Alex Ter Beek ◽  
Bart J. F. Keijser ◽  
Andre Boorsma ◽  
Anna Zakrzewska ◽  
Rick Orij ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Plasma Membrane ◽  
Nutrient Limitation ◽  
Fatty Acid Biosynthesis ◽  
Sorbic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Transcriptional Profiling ◽  
Acid Stress ◽  
Resistance Mechanisms ◽  
Membrane Remodeling

ABSTRACT The weak organic acid sorbic acid is a commonly used food preservative, as it inhibits the growth of bacteria, yeasts, and molds. We have used genome-wide transcriptional profiling of Bacillus subtilis cells during mild sorbic acid stress to reveal the growth-inhibitory activity of this preservative and to identify potential resistance mechanisms. Our analysis demonstrated that sorbic acid-stressed cells induce responses normally seen upon nutrient limitation. This is indicated by the strong derepression of the CcpA, CodY, and Fur regulon and the induction of tricarboxylic acid cycle genes, SigL- and SigH-mediated genes, and the stringent response. Intriguingly, these conditions did not lead to the activation of sporulation, competence, or the general stress response. The fatty acid biosynthesis (fab) genes and BkdR-regulated genes are upregulated, which may indicate plasma membrane remodeling. This was further supported by the reduced sensitivity toward the fab inhibitor cerulenin upon sorbic acid stress. We are the first to present a comprehensive analysis of the transcriptional response of B. subtilis to sorbic acid stress.

scholarly journals Cargo induces retromer-mediated membrane remodeling on membranes

2018 ◽  
Vol 29 (22) ◽  
pp. 2709-2719 ◽  
Author(s):  
Latha Kallur Purushothaman ◽  
Christian Ungermann
Keyword(s):  
Plasma Membrane ◽  
Simple Model ◽  
Membrane Proteins ◽  
Golgi Complex ◽  
Exact Order ◽  
Membrane Remodeling ◽  
Sorting Nexin ◽  
Low Concentrations ◽  
Sorting Station ◽  
Specific Trigger

Endosomes serve as a central sorting station of lipids and proteins that arrive via vesicular carrier from the plasma membrane and the Golgi complex. At the endosome, retromer complexes sort selected receptors and membrane proteins into tubules or vesicles that bud off the endosome. The mature endosome finally fuses with the lysosome. Retromer complexes consist of a cargo selection complex (CSC) and a membrane remodeling part (sorting nexin [SNX]-Bin/amphiphysin/Rvs [BAR], or Snx3 in yeast) and different assemblies of retromer mediate recycling of different cargoes. Due to this complexity, the exact order of events that results in carrier formation is not yet understood. Here, we reconstituted this process on giant unilamellar vesicles together with purified retromer complexes from yeast and selected cargoes. Our data reveal that the membrane remodeling activity of both Snx3 and the SNX-BAR complex is strongly reduced at low concentrations, which can be reactivated by CSC. At even lower concentrations, these complexes still associate with membranes, but only remodel membranes in the presence of their specific cargoes. Our data thus favor a simple model, where cargo functions as a specific trigger of retromer-mediated sorting on endosomes.

scholarly journals Differential disruption of autoinhibition and defect in assembly of cytoskeleton during cell division decide the fate of human DIAPH1-related cytoskeletopathy

2019 ◽  
Vol 56 (12) ◽  
pp. 818-827 ◽  
Author(s):  
Bong Jik Kim ◽  
Takehiko Ueyama ◽  
Takushi Miyoshi ◽  
Seungmin Lee ◽  
Jin Hee Han ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Plasma Membrane ◽  
Cell Division ◽  
Blood Cell ◽  
Clinical Severity ◽  
Hydrophobic Pocket ◽  
Constitutive Activation ◽  
Whole Exome ◽  
Differential Cell ◽  
Inhibitory Domain

BackgroundDiaphanous-related formin 1 (DIA1), which assembles the unbranched actin microfilament and microtubule cytoskeleton, is encoded by DIAPH1. Constitutive activation by the disruption of autoinhibitory interactions between the N-terminal diaphanous inhibitory domain (DID) and C-terminal diaphanous autoregulatory domain (DAD) dysregulates DIA1, resulting in both hearing loss and blood cell abnormalities.Methods and resultsHere, we report the first constitutively active mutant in the DID (p.A265S) of humans with only hearing loss and not blood cell abnormality through whole exome sequencing. The previously reported DAD mutants and our DID mutant (p.A265S) shared the finding of diminished autoinhibitory interaction, abnormally upregulated actin polymerisation activity and increased localisations at the plasma membrane. However, the obvious defect in the DIA1-driven assembly of cytoskeleton ‘during cell division’ was only from the DAD mutants, not from p.A265S, which did not show any blood cell abnormality. We also evaluated the five DID mutants in the hydrophobic pocket since four of these five additional mutants were predicted to critically disrupt interaction between the DID and DAD. These additional pathogenic DID mutants revealed varying degrees of defect in the DIA1-driven cytoskeleton assembly, including nearly normal phenotype during cell division as well as obvious impaired autoinhibition, again coinciding with our key observation in DIA1 mutant (p.A265S) in the DID.ConclusionHere, we report the first mutant in the DID of humans with only hearing loss. The differential cell biological phenotypes of DIA1 during cell division appear to be potential determinants of the clinical severity of DIAPH1-related cytoskeletopathy in humans.

scholarly journals TOR complex 2 (TORC2) signaling and the ESCRT machinery cooperate in the protection of plasma membrane integrity in yeast

2020 ◽  
Vol 295 (34) ◽  
pp. 12028-12044
Author(s):  
Oliver Schmidt ◽  
Yannick Weyer ◽  
Simon Sprenger ◽  
Michael A. Widerin ◽  
Sebastian Eising ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Integrity ◽  
Homeostatic Regulation ◽  
Membrane Tension ◽  
Membrane Remodeling ◽  
Plasma Membrane Integrity ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Evolutionarily Conserved ◽  
Calcineurin Activity

The endosomal sorting complexes required for transport (ESCRT) mediate evolutionarily conserved membrane remodeling processes. Here, we used budding yeast (Saccharomyces cerevisiae) to explore how the ESCRT machinery contributes to plasma membrane (PM) homeostasis. We found that in response to reduced membrane tension and inhibition of TOR complex 2 (TORC2), ESCRT-III/Vps4 assemblies form at the PM and help maintain membrane integrity. In turn, the growth of ESCRT mutants strongly depended on TORC2-mediated homeostatic regulation of sphingolipid (SL) metabolism. This was caused by calcineurin-dependent dephosphorylation of Orm2, a repressor of SL biosynthesis. Calcineurin activity impaired Orm2 export from the endoplasmic reticulum (ER) and thereby hampered its subsequent endosome and Golgi-associated degradation (EGAD). The ensuing accumulation of Orm2 at the ER in ESCRT mutants necessitated TORC2 signaling through its downstream kinase Ypk1, which repressed Orm2 and prevented a detrimental imbalance of SL metabolism. Our findings reveal compensatory cross-talk between the ESCRT machinery, calcineurin/TORC2 signaling, and the EGAD pathway important for the regulation of SL biosynthesis and the maintenance of PM homeostasis.

scholarly journals Omega-3 Fatty Acids Modulate TRPV4 Function through Plasma Membrane Remodeling

Cell Reports ◽  
2017 ◽  
Vol 21 (1) ◽  
pp. 246-258 ◽  
Author(s):  
Rebeca Caires ◽  
Francisco J. Sierra-Valdez ◽  
Jonathan R.M. Millet ◽  
Joshua D. Herwig ◽  
Esra Roan ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Plasma Membrane ◽  
Omega 3 Fatty Acids ◽  
Membrane Remodeling ◽  
Omega 3
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