Membrane curvature and the control of GTP hydrolysis in Arf1 during COPI vesicle formation

2005 ◽  
Vol 33 (4) ◽  
pp. 619-622 ◽  
Author(s):  
B. Antonny ◽  
J. Bigay ◽  
J.-F. Casella ◽  
G. Drin ◽  
B. Mesmin ◽  
...  
Keyword(s):  
Lipid Membranes ◽  
Membrane Curvature ◽  
Gtp Hydrolysis ◽  
Membrane Fission ◽  
Transport Vesicles ◽  
Highly Sensitive ◽  
Copi Vesicle ◽  
Membrane Budding ◽  
Gtpase Cycle ◽  
Adp Ribosylation Factor

The GTP switch of the small G-protein Arf1 (ADP-ribosylation factor 1) on lipid membranes promotes the polymerization of the COPI (coat protein complex I) coat, which acts as a membrane deforming shell to form transport vesicles. Real-time measurements for coat assembly on liposomes gives insights into how the GTPase cycle of Arf1 is coupled in time with the polymerization of the COPI coat and the resulting membrane deformation. One key parameter seems to be the membrane curvature. Arf-GAP1 (where GAP stands for GTPase-activating protein), which promotes GTP hydrolysis in the Arf1–COPI complex is highly sensitive to lipid packing. Its activity on Arf1-GTP increases by two orders of magnitude as the diameter of the liposomes approaches that of authentic transport vesicles (60 nm). This suggests that during membrane budding, Arf1-GTP molecules are progressively eliminated from the coated area where the membrane curvature is positive, but are protected from Arf-GAP1 at the bud neck due to the negative curvature of this region. As a result, the coat should be stable as long as the bud remains attached and should disassemble as soon as membrane fission occurs.

scholarly journals Discrete Determinants in ArfGAP2/3 Conferring Golgi Localization and Regulation by the COPI Coat

2009 ◽  
Vol 20 (3) ◽  
pp. 859-869 ◽  
Author(s):  
Lena Kliouchnikov ◽  
Joëlle Bigay ◽  
Bruno Mesmin ◽  
Anna Parnis ◽  
Moran Rawet ◽  
...  
Keyword(s):  
Lipid Membranes ◽  
Membrane Curvature ◽  
In Vitro Assays ◽  
Minor Role ◽  
Gtp Hydrolysis ◽  
Gtpase Activating Proteins ◽  
Golgi Localization ◽  
Adp Ribosylation Factor ◽  
Fusion Approach

From yeast to mammals, two types of GTPase-activating proteins, ArfGAP1 and ArfGAP2/3, control guanosine triphosphate (GTP) hydrolysis on the small G protein ADP-ribosylation factor (Arf) 1 at the Golgi apparatus. Although functionally interchangeable, they display little similarity outside the catalytic GTPase-activating protein (GAP) domain, suggesting differential regulation. ArfGAP1 is controlled by membrane curvature through its amphipathic lipid packing sensor motifs, whereas Golgi targeting of ArfGAP2 depends on coatomer, the building block of the COPI coat. Using a reporter fusion approach and in vitro assays, we identified several functional elements in ArfGAP2/3. We show that the Golgi localization of ArfGAP3 depends on both a central basic stretch and a carboxy-amphipathic motif. The basic stretch interacts directly with coatomer, which we found essential for the catalytic activity of ArfGAP3 on Arf1-GTP, whereas the carboxy-amphipathic motif interacts directly with lipid membranes but has minor role in the regulation of ArfGAP3 activity. Our findings indicate that the two types of ArfGAP proteins that reside at the Golgi use a different combination of protein–protein and protein–lipid interactions to promote GTP hydrolysis in Arf1-GTP.

scholarly journals Coatomer and dimeric ADP ribosylation factor 1 promote distinct steps in membrane scission

2011 ◽  
Vol 194 (5) ◽  
pp. 765-777 ◽  
Author(s):  
Rainer Beck ◽  
Simone Prinz ◽  
Petra Diestelkötter-Bachert ◽  
Simone Röhling ◽  
Frank Adolf ◽  
...  
Keyword(s):  
Membrane Curvature ◽  
Coated Vesicles ◽  
Cross Linking ◽  
Vesicle Release ◽  
Reconstituted System ◽  
Copi Vesicle ◽  
Membrane Scission ◽  
Adp Ribosylation Factor ◽  
Chemical Cross Linking

Formation of coated vesicles requires two striking manipulations of the lipid bilayer. First, membrane curvature is induced to drive bud formation. Second, a scission reaction at the bud neck releases the vesicle. Using a reconstituted system for COPI vesicle formation from purified components, we find that a dimerization-deficient Arf1 mutant, which does not display the ability to modulate membrane curvature in vitro or to drive formation of coated vesicles, is able to recruit coatomer to allow formation of COPI-coated buds but does not support scission. Chemical cross-linking of this Arf1 mutant restores vesicle release. These experiments show that initial curvature of the bud is defined primarily by coatomer, whereas the membrane curvature modulating activity of dimeric Arf1 is required for membrane scission.

scholarly journals Cardiolipin-Containing Lipid Membranes Attract the Bacterial Cell Division Protein DivIVA

2021 ◽  
Vol 22 (15) ◽  
pp. 8350
Author(s):  
Naďa Labajová ◽  
Natalia Baranova ◽  
Miroslav Jurásek ◽  
Robert Vácha ◽  
Martin Loose ◽  
...  
Keyword(s):  
Cell Division ◽  
Lipid Bilayers ◽  
Bacterial Cell ◽  
Lipid Membranes ◽  
Model Organism ◽  
Active Role ◽  
Membrane Curvature ◽  
Bacterial Cell Division ◽  
Division Site ◽  
Clostridioides Difficile

DivIVA is a protein initially identified as a spatial regulator of cell division in the model organism Bacillus subtilis, but its homologues are present in many other Gram-positive bacteria, including Clostridia species. Besides its role as topological regulator of the Min system during bacterial cell division, DivIVA is involved in chromosome segregation during sporulation, genetic competence, and cell wall synthesis. DivIVA localizes to regions of high membrane curvature, such as the cell poles and cell division site, where it recruits distinct binding partners. Previously, it was suggested that negative curvature sensing is the main mechanism by which DivIVA binds to these specific regions. Here, we show that Clostridioides difficile DivIVA binds preferably to membranes containing negatively charged phospholipids, especially cardiolipin. Strikingly, we observed that upon binding, DivIVA modifies the lipid distribution and induces changes to lipid bilayers containing cardiolipin. Our observations indicate that DivIVA might play a more complex and so far unknown active role during the formation of the cell division septal membrane.

Single Vesicle Analysis Reveals Nanoscale Membrane Curvature Selective Pore Formation in Lipid Membranes by an Antiviral α-Helical Peptide

Nano Letters ◽  
2012 ◽  
Vol 12 (11) ◽  
pp. 5719-5725 ◽  
Author(s):  
Seyed R. Tabaei ◽  
Michael Rabe ◽  
Vladimir P. Zhdanov ◽  
Nam-Joon Cho ◽  
Fredrik Höök
Keyword(s):  
Lipid Membranes ◽  
Pore Formation ◽  
Membrane Curvature ◽  
Helical Peptide ◽  
Single Vesicle

scholarly journals Septin ring assembly involves cycles of GTP loading and hydrolysis by Cdc42p

2002 ◽  
Vol 156 (2) ◽  
pp. 315-326 ◽  
Author(s):  
Amy S. Gladfelter ◽  
Indrani Bose ◽  
Trevin R. Zyla ◽  
Elaine S.G. Bardes ◽  
Daniel J. Lew
Keyword(s):  
Transcriptional Activation ◽  
Gtpase Activating Protein ◽  
Gtp Hydrolysis ◽  
Septin Ring ◽  
Turn On ◽  
Ring Assembly ◽  
Bud Emergence ◽  
Assembly Factor ◽  
Gtpase Cycle ◽  
Budding Yeast Cell Cycle

At the beginning of the budding yeast cell cycle, the GTPase Cdc42p promotes the assembly of a ring of septins at the site of future bud emergence. Here, we present an analysis of cdc42 mutants that display specific defects in septin organization, which identifies an important role for GTP hydrolysis by Cdc42p in the assembly of the septin ring. The mutants show defects in basal or stimulated GTP hydrolysis, and the septin misorganization is suppressed by overexpression of a Cdc42p GTPase-activating protein (GAP). Other mutants known to affect GTP hydrolysis by Cdc42p also caused septin misorganization, as did deletion of Cdc42p GAPs. In performing its roles in actin polarization and transcriptional activation, GTP-Cdc42p is thought to function by activating and/or recruiting effectors to the site of polarization. Excess accumulation of GTP-Cdc42p due to a defect in GTP hydrolysis by the septin-specific alleles might cause unphysiological activation of effectors, interfering with septin assembly. However, the recessive and dose-sensitive genetic behavior of the septin-specific cdc42 mutants is inconsistent with the septin defect stemming from a dominant interference of this type. Instead, we suggest that assembly of the septin ring involves repeated cycles of GTP loading and GTP hydrolysis by Cdc42p. These results suggest that a single GTPase, Cdc42p, can act either as a ras-like GTP-dependent “switch” to turn on effectors or as an EF-Tu–like “assembly factor” using the GTPase cycle to assemble a macromolecular structure.

Molecular Cloning and Structure Analysis of MpARF, an ADP-Ribosylation Factor in Monascus purpureus

2014 ◽  
Vol 884-885 ◽  
pp. 574-577
Author(s):  
Lan Gao ◽  
Bi Yun Zhu
Keyword(s):  
Homo Sapiens ◽  
Three Dimensional ◽  
Monascus Purpureus ◽  
Protein Fold ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Gtp Hydrolysis ◽  
Adp Ribosylation ◽  
Vesicular Membrane ◽  
Adp Ribosylation Factor

ADP-ribosylation factors (ARF) are ubiquitous regulators of vesicular membrane traffic in all eukaryotic cells. A full-length cDNA encoding an ARF was cloned from the cDNA library ofMonascus purpureus. The cDNA was 1275 bp in length, contains a predicted 555 bp ORF that encodes 184 amino acids, the gene was designated MpARF. The deduced amino acid sequence showed high homology to ARF6 ofHomo sapiens, ARFB ofAspergillus nidulansand ARF3p ofSaccharomyces cerevisiae, including conserved N-terminal myristoylation site, GTP binding and GTP hydrolysis site, suggesting that the MpARF is a member of the ARF6 protein family. A typical G protein fold three-dimensional model of MpARF was built; the structure is similar to the structure of human ARF6. According to the functions of ARFB and ARF3p in fungi, we implicated that the MpARF would involved in hyphal polarized growth.

scholarly journals Accumulation of rab4GTP in the Cytoplasm and Association with the Peptidyl-Prolyl Isomerase Pin1 during Mitosis

2000 ◽  
Vol 11 (7) ◽  
pp. 2201-2211 ◽  
Author(s):  
Lisya Gerez ◽  
Karin Mohrmann ◽  
Marcel van Raak ◽  
Mandy Jongeneelen ◽  
Xiao Zhen Zhou ◽  
...  
Keyword(s):  
Membrane Transport ◽  
Subcellular Fractionation ◽  
Effector Proteins ◽  
Endocytic Pathway ◽  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase ◽  
Transport Vesicles ◽  
Early Endosomes ◽  
Gtpase Cycle ◽  
Mitotic Cells

Transport through the endocytic pathway is inhibited during mitosis. The mechanism responsible for this inhibition is not understood. Rab4 might be one of the proteins involved as it regulates transport through early endosomes, is phosphorylated by p34cdc2 kinase, and is translocated from early endosomes to the cytoplasm during mitosis. We investigated the perturbation of the rab4 GTPase cycle during mitosis. Newly synthesized rab4 was less efficiently targeted to membranes during mitosis. By subcellular fractionation of mitotic cells, we found a large increase of cytosolic rab4 in the active GTP-form, an increase not associated with the cytosolic rabGDP chaperone GDI. Instead, phosphorylated rab4 is in a complex with the peptidyl-prolyl isomerase Pin1 during mitosis, but not during interphase. Our results show that less efficient recruitment of rab4 to membranes and a bypass of the normal GDI-mediated retrieval of rab4GDP from early endosomes reduce the amount of rab4GTP on membranes during mitosis. We propose that phosphorylation of rab4 inhibits both the recruitment of rab4 effector proteins to early endosomes and the docking of rab4-containing transport vesicles. This mechanism might contribute to the inhibition of endocytic membrane transport during mitosis.

Membrane re-modelling by BAR domain superfamily proteins via molecular and non-molecular factors

2018 ◽  
Vol 46 (2) ◽  
pp. 379-389 ◽  
Author(s):  
Tamako Nishimura ◽  
Nobuhiro Morone ◽  
Shiro Suetsugu
Keyword(s):  
Lipid Membranes ◽  
Intracellular Transport ◽  
Lipid Membrane ◽  
Membrane Curvature ◽  
Membrane Dynamics ◽  
Cytoskeletal Proteins ◽  
Cellular Functions ◽  
High Concentration ◽  
Bar Domain ◽  
Intracellular Organelles

Lipid membranes are structural components of cell surfaces and intracellular organelles. Alterations in lipid membrane shape are accompanied by numerous cellular functions, including endocytosis, intracellular transport, and cell migration. Proteins containing Bin–Amphiphysin–Rvs (BAR) domains (BAR proteins) are unique, because their structures correspond to the membrane curvature, that is, the shape of the lipid membrane. BAR proteins present at high concentration determine the shape of the membrane, because BAR domain oligomers function as scaffolds that mould the membrane. BAR proteins co-operate with various molecular and non-molecular factors. The molecular factors include cytoskeletal proteins such as the regulators of actin filaments and the membrane scission protein dynamin. Lipid composition, including saturated or unsaturated fatty acid tails of phospholipids, also affects the ability of BAR proteins to mould the membrane. Non-molecular factors include the external physical forces applied to the membrane, such as tension and friction. In this mini-review, we will discuss how the BAR proteins orchestrate membrane dynamics together with various molecular and non-molecular factors.

scholarly journals Coordination of the leucine-sensing Rag GTPase cycle by leucyl-tRNA synthetase in the mTORC1 signaling pathway

2018 ◽  
Vol 115 (23) ◽  
pp. E5279-E5288 ◽  
Author(s):  
Minji Lee ◽  
Jong Hyun Kim ◽  
Ina Yoon ◽  
Chulho Lee ◽  
Mohammad Fallahi Sichani ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Trna Synthetase ◽  
Gtp Hydrolysis ◽  
Mtorc1 Signaling ◽  
Amino Acid Sensing ◽  
Gtpase Cycle ◽  
Rag Gtpase ◽  
Cancer Tissues ◽  
Mtorc1 Activation ◽  
Hydrolysis Of

A protein synthesis enzyme, leucyl-tRNA synthetase (LRS), serves as a leucine sensor for the mechanistic target of rapamycin complex 1 (mTORC1), which is a central effector for protein synthesis, metabolism, autophagy, and cell growth. However, its significance in mTORC1 signaling and cancer growth and its functional relationship with other suggested leucine signal mediators are not well-understood. Here we show the kinetics of the Rag GTPase cycle during leucine signaling and that LRS serves as an initiating “ON” switch via GTP hydrolysis of RagD that drives the entire Rag GTPase cycle, whereas Sestrin2 functions as an “OFF” switch by controlling GTP hydrolysis of RagB in the Rag GTPase–mTORC1 axis. The LRS–RagD axis showed a positive correlation with mTORC1 activity in cancer tissues and cells. The GTP–GDP cycle of the RagD–RagB pair, rather than the RagC–RagA pair, is critical for leucine-induced mTORC1 activation. The active RagD–RagB pair can overcome the absence of the RagC–RagA pair, but the opposite is not the case. This work suggests that the GTPase cycle of RagD–RagB coordinated by LRS and Sestrin2 is critical for controlling mTORC1 activation, and thus will extend the current understanding of the amino acid-sensing mechanism.

Sign in / Sign up

Export Citation Format

Share Document