scholarly journals Missing-in-metastasis and IRSp53 deform PI(4,5)P2-rich membranes by an inverse BAR domain–like mechanism

2007 ◽  
Vol 176 (7) ◽  
pp. 953-964 ◽  
Author(s):  
Pieta K. Mattila ◽  
Anette Pykäläinen ◽  
Juha Saarikangas ◽  
Ville O. Paavilainen ◽  
Helena Vihinen ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Membrane Curvature ◽  
Membrane Dynamics ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Tubular Structures ◽  
Membrane Deformation ◽  
Bar Domain ◽  
Membrane Protrusions ◽  
Induce Plasma

The actin cytoskeleton plays a fundamental role in various motile and morphogenetic processes involving membrane dynamics. We show that actin-binding proteins MIM (missing-in-metastasis) and IRSp53 directly bind PI(4,5)P2-rich membranes and deform them into tubular structures. This activity resides in the N-terminal IRSp53/MIM domain (IMD) of these proteins, which is structurally related to membrane-tubulating BAR (Bin/amphiphysin/Rvs) domains. We found that because of a difference in the geometry of the PI(4,5)P2-binding site, IMDs induce a membrane curvature opposite that of BAR domains and deform membranes by binding to the interior of the tubule. This explains why IMD proteins induce plasma membrane protrusions rather than invaginations. We also provide evidence that the membrane-deforming activity of IMDs, instead of the previously proposed F-actin–bundling or GTPase-binding activities, is critical for the induction of the filopodia/microspikes in cultured mammalian cells. Together, these data reveal that interplay between actin dynamics and a novel membrane-deformation activity promotes cell motility and morphogenesis.

scholarly journals Control of actin polymerization via the coincidence of phosphoinositides and high membrane curvature

2017 ◽  
Vol 216 (11) ◽  
pp. 3745-3765 ◽  
Author(s):  
Frederic Daste ◽  
Astrid Walrant ◽  
Mikkel R. Holst ◽  
Jonathan R. Gadsby ◽  
Julia Mason ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Actin Polymerization ◽  
Kinase Inhibitors ◽  
Mammalian Cell Culture ◽  
Membrane Curvature ◽  
Coated Pits ◽  
Bar Domain ◽  
Oculocerebrorenal Syndrome ◽  
Cascade Amplification ◽  
Hydrolysis Of

The conditional use of actin during clathrin-mediated endocytosis in mammalian cells suggests that the cell controls whether and how actin is used. Using a combination of biochemical reconstitution and mammalian cell culture, we elucidate a mechanism by which the coincidence of PI(4,5)P2 and PI(3)P in a curved vesicle triggers actin polymerization. At clathrin-coated pits, PI(3)P is produced by the INPP4A hydrolysis of PI(3,4)P2, and this is necessary for actin-driven endocytosis. Both Cdc42⋅guanosine triphosphate and SNX9 activate N-WASP–WIP- and Arp2/3-mediated actin nucleation. Membrane curvature, PI(4,5)P2, and PI(3)P signals are needed for SNX9 assembly via its PX–BAR domain, whereas signaling through Cdc42 is activated by PI(4,5)P2 alone. INPP4A activity is stimulated by high membrane curvature and synergizes with SNX9 BAR domain binding in a process we call curvature cascade amplification. We show that the SNX9-driven actin comets that arise on human disease–associated oculocerebrorenal syndrome of Lowe (OCRL) deficiencies are reduced by inhibiting PI(3)P production, suggesting PI(3)P kinase inhibitors as a therapeutic strategy in Lowe syndrome.

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 A direct proof that sole actin dynamics drive membrane deformations

2018 ◽  
Author(s):  
Camille Simon ◽  
Rémy Kusters ◽  
Valentina Caorsi ◽  
Antoine Allard ◽  
Majdouline Abou-Ghali ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Actin Polymerization ◽  
Cell Function ◽  
Turgor Pressure ◽  
Direct Proof ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Associated Proteins ◽  
Low Tension ◽  
Membrane Deformations

AbstractCell membrane deformations are crucial for proper cell function. Specialized protein assemblies initiate inward or outward membrane deformations that turn into, for example, filopodia or endocytic intermediates. Actin dynamics and actin-binding proteins are involved in this process, although their detailed role remains controversial. We show here that a dynamic, branched actin network is sufficient, in absence of any membrane-associated proteins, to initiate both inward and outward membrane deformation. With actin polymerization triggered at the membrane of liposomes, we produce inward filopodia-like structures at low tension, while outward endocytosis-like structures are robustly generated regardless of tension. Our results are reminiscent of endocytosis in mammalian cells, where actin polymerization forces are required when membrane tension is increased, and in yeast, where they are always required to overcome the opposing turgor pressure. By combining experimental observations with physical modeling, we propose a mechanism for actin-driven endocytosis under high tension or high pressure conditions.

scholarly journals Dimerization is necessary for MIM-mediated membrane deformation and endocytosis

2012 ◽  
Vol 446 (3) ◽  
pp. 469-475 ◽  
Author(s):  
Meng Cao ◽  
Tailan Zhan ◽  
Min Ji ◽  
Xi Zhan
Keyword(s):  
Metastasis Suppressor ◽  
Intracellular Protein ◽  
High Potency ◽  
Membrane Deformation ◽  
Bar Domain ◽  
Membrane Protrusions ◽  
Metastasis Suppressor 1 ◽  
Intrinsic Capacity ◽  
Transferrin Uptake

MIM [missing in metastasis; also called MTSS1 (metastasis suppressor 1)] is an intracellular protein that binds to actin and cortactin and has an intrinsic capacity to sense and facilitate the formation of protruded membranous curvatures implicated in cell-ular polarization, mobilization and endocytosis. The N-terminal 250 amino acids of MIM undergo homodimerization and form a structural module with the characteristic of an I-BAR [inverse BAR (Bin/amphiphysin/Rvs)] domain. To discern the role of the dimeric configuration in the function of MIM, we designed several peptides able to interfere with MIM dimerization in a manner dependent upon their lengths. Overexpression of one of the peptides effectively abolished MIM-mediated membrane protrusions and transferrin uptake. However, a peptide with a high potency inhibiting MIM dimerization failed to affect its binding to actin and cortactin. Thus the results of the present study indicate that the dimeric configuration is essential for MIM-mediated membrane remodelling and serves as a proper target to develop antagonists specifically against an I-BAR-domain-containing protein.

scholarly journals Regulation of membrane scission in yeast endocytosis

2021 ◽  
Author(s):  
Deepikaa Menon ◽  
Marko Kaksonen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mammalian Cells ◽  
Genetic Manipulation ◽  
Sh3 Domain ◽  
Membrane Curvature ◽  
Yeast Cells ◽  
Vesicle Formation ◽  
Type I ◽  
Bar Domain ◽  
Membrane Scission

During clathrin-mediated endocytosis, a flat plasma membrane is shaped into an invagination that undergoes scission to form a vesicle. In mammalian cells, the force that drives the transition from invagination to vesicle is primarily provided by the GTPase dynamin that acts in concert with crescent-shaped BAR domain proteins. In yeast cells, the mechanism of endocytic scission is unclear. The yeast BAR domain protein complex Rvs161/167 (Rvs) nevertheless plays an important role in this process: deletion of Rvs dramatically reduces scission efficiency. A mechanistic understanding of the influence of Rvs on scission however, remains incomplete. We used quantitative live-cell imaging and genetic manipulation to understand the recruitment and function of Rvs and other late-stage proteins at yeast endocytic sites. We found that arrival of Rvs at endocytic sites is timed by interaction of its BAR domain with specific membrane curvature. A second domain of Rvs167- the SH3 domain- affects localization efficiency of Rvs. We show that Myo3, one of the two type-I myosins in Saccharomyces cerevisiae, has a role in recruiting Rvs167 via the SH3 domain. Removal of the SH3 domain also affects assembly and disassembly of actin and impedes membrane invagination. Our results indicate that both BAR and SH3 domains are important for the role of Rvs as a regulator of scission. We tested other proteins implicated in vesicle formation in Saccharomyces cerevisiae , and found that neither synaptojanins nor dynamin contribute directly to membrane scission. We propose that recruitment of Rvs BAR domains delays scission and allows invaginations to grow by stabilizing them. We also propose that vesicle formation is dependent on the force exerted by the actin network component of the endocytic machinery.

scholarly journals Role of Phosphoinositides in Cellular Signaling, Functions and Diseases

2020 ◽  
Author(s):  
Kalpana Mandal
Keyword(s):  
Cell Signaling ◽  
Transmembrane Proteins ◽  
Adaptor Proteins ◽  
Membrane Curvature ◽  
Membrane Dynamics ◽  
Actin Binding ◽  
Coated Pits ◽  
Cytoskeletal Dynamics ◽  
Actin Cytoskeletal Dynamics

In this review we summarize the recent development in understanding the role of PIP2 in cellular function and signaling. We first discuss the effect of PIP2 on actin binding proteins addressing the mechanism of the actin cytoskeletal dynamics such as polymerization or depolymerization of the filamentous network or the coupling to membrane to generate forces. Next, we outline the role of PIP2 in membrane dynamics. We summarized how the membrane organization depends upon PIP2 in the presence of ions or transmembrane proteins that are sensitive to membrane curvature. We discuss how clathrin coated pits interact with adaptor proteins during the endocytosis process, which is facilitated by PIP2. Finally, we discuss the role of PIP2 in cell signaling and diseases.

scholarly journals Ezrin enrichment on curved membranes requires a specific conformation or interaction with a curvature-sensitive partner

2018 ◽  
Author(s):  
Feng-Ching Tsai ◽  
Aurélie Bertin ◽  
Hugo Bousquet ◽  
John Manzi ◽  
Yosuke Senju ◽  
...  
Keyword(s):  
Cell Biology ◽  
Membrane Curvature ◽  
Bar Domain ◽  
Negatively Curved ◽  
Current Cell ◽  
Bar Domain Proteins ◽  
Membrane Protrusions ◽  
Curved Membranes ◽  
Curved Membrane

AbstractOne challenge in current cell biology is to decipher the biophysical mechanisms governing protein enrichment on curved membranes and the resulting membrane deformation. The ERM protein ezrin is abundant and associated with cellular membranes that are flat or with positive or negative curvatures. Using in vitro and cell biology approaches, we assess mechanisms of ezrin’s enrichment on curved membranes. We evidence that ezrin (ezrinWT) and its phosphomimetic mutant T567D (ezrinTD) do not deform membranes but self-assemble anti-parallelly, zipping adjacent membranes. EzrinTD’s specific conformation reduces intermolecular ezrin interactions, allows binding to actin filaments, and promotes ezrin binding to positively curved membranes. While neither ezrinTD nor ezrinWT senses negative membrane curvature alone, we demonstrate that interacting with curvature sensors I-BAR-domain proteins facilitates ezrin enrichment in negatively curved membrane protrusions. Overall, our work reveals new mechanisms, specific conformation or binding to a curvature sensor partner, for targeting curvature insensitive proteins to curved membranes.

scholarly journals Light-inducible generation of membrane curvature in live cells with engineered BAR domain proteins

2020 ◽  
Author(s):  
Taylor Jones ◽  
Aofei Liu ◽  
Bianxiao Cui
Keyword(s):  
Blue Light ◽  
Intracellular Signaling ◽  
Positive Curvature ◽  
Membrane Curvature ◽  
Actin Dynamics ◽  
Live Cells ◽  
Light Illumination ◽  
List Type ◽  
Bar Domain ◽  
Bar Domain Proteins

AbstractNanoscale membrane curvature is now understood to play an active role in essential cellular processes such as endocytosis, exocytosis and actin dynamics. Previous studies have shown that membrane curvatures directly affect protein functions and intracellular signaling. However, few methods are able to precisely manipulate membrane curvature in live cells. Here, we report the development of a new method of generating nanoscale membrane curvature in live cells that is controllable, reversible, and capable of precise spatial and temporal manipulation. For this purpose, we make use of BAR domain proteins, a family of well-studied membrane-remodeling and membrane-sculpting proteins. Specifically, we engineered two optogenetic systems, opto-FBAR and opto-IBAR, that allow light-inducible formation of positive and negative membrane curvature respectively. Using opto-FBAR, blue light activation results in the formation of tubular membrane invaginations (positive curvature), controllable down to the subcellular level. Using opto-IBAR, blue light illumination results in the formation of membrane protrusions or filopodia (negative curvature). These systems present a novel approach for light-inducible manipulation of nanoscale membrane curvature in live cells.HighlightsOpto-FBAR enables light-inducible positive membrane curvature formation.Opto-IBAR enables light-inducible negative membrane curvature formation.Light-inducible activation enables precise spatial and temporal control.Opto-BAR systems present a new approach for studying membranes in live cells.

The Role of BAR Domain Proteins in the Regulation of Membrane Dynamics

Acta Naturae ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 60-69 ◽  
Author(s):  
T. B. Stanishneva-Konovalova ◽  
N. I Derkacheva ◽  
S. V. Polevova ◽  
O. S. Sokolova
Keyword(s):  
Membrane Dynamics ◽  
Actin Dynamics ◽  
Membrane Remodeling ◽  
Bar Domain ◽  
Cellular Processes ◽  
Functional Differences ◽  
Bar Domain Proteins ◽  
Domain Protein ◽  
Bar Domains

Many cellular processes are associated with membrane remodeling. The BAR domain protein family plays a key role in the formation and detection of local membrane curvatures and in attracting other proteins, including the regulators of actin dynamics. Based on their structural and phylogenetic properties, BAR domains are divided into several groups which affect membrane in various ways and perform different functions in cells. However, recent studies have uncovered evidence of functional differences even within the same group. This review discusses the principles underlying the interactions of different groups of BAR domains, and their individual representatives, with membranes.

scholarly journals Coactosin Phosphorylation Controls Entamoeba histolytica Cell Membrane Protrusions and Cell Motility

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Muhammad M. Hasan ◽  
José E. Teixeira ◽  
Ying-Wai Lam ◽  
Christopher D. Huston
Keyword(s):  
Extracellular Matrix ◽  
Cell Membrane ◽  
Cell Motility ◽  
Protein Phosphorylation ◽  
Entamoeba Histolytica ◽  
Membrane Dynamics ◽  
Actin Binding ◽  
Content Type ◽  
Phosphorylated Proteins ◽  
Membrane Protrusions

ABSTRACT Invasion of the colon wall by Entamoeba histolytica during amoebic dysentery entails migration of trophozoites through tissue layers that are rich in extracellular matrix. Transcriptional silencing of the E. histolytica surface metalloprotease EhMSP-1 produces hyperadherent less-motile trophozoites that are deficient in forming invadosomes. Reversible protein phosphorylation is often implicated in regulation of cell motility and invadosome formation. To identify such intermediaries of the EhMSP-1-silenced phenotype, here we compared the phosphoproteomes of EhMSP-1-silenced and vector control trophozoites by using quantitative tandem mass spectrometry-based proteomics. Six proteins were found to be differentially phosphorylated in EhMSP-1-silenced and control cells, including EhCoactosin, a member of the ADF/cofilin family of actin-binding proteins, which was more frequently phosphorylated at serine 147. Regulated overexpression of wild-type, phosphomimetic, and nonphosphorylatable EhCoactosin variants was used to test if phosphorylation functions in control of E. histolytica actin dynamics. Each of the overexpressed proteins colocalized with F-actin during E. histolytica phagocytosis. Nonetheless, trophozoites overexpressing an EhCoactosin phosphomimetic mutant formed more and poorly coordinated cell membrane protrusions compared to those in control or cells expressing a nonphosphorylatable mutant, while trophozoites overexpressing nonphosphorylatable EhCoactosin were significantly more motile within a model of mammalian extracellular matrix. Therefore, although EhCoactosin’s actin-binding ability appeared unaffected by phosphorylation, EhCoactosin phosphorylation helps to regulate amoebic motility. These data help to understand the mechanisms underlying altered adherence and motility in EhMSP-1-silenced trophozoites and lay the groundwork for identifying kinases and phosphatases critical for control of amoebic invasiveness. IMPORTANCE Invasive amoebiasis, caused by the intestinal parasite Entamoeba histolytica, causes life-threatening diarrhea and liver abscesses, but, for unknown reasons, only approximately 10% of E. histolytica infections become symptomatic. A key requirement of invasion is the ability of the parasite to migrate through tissue layers. Here, we systematically looked for differences in protein phosphorylation between control parasites and a previously identified hyperadherent E. histolytica cell line that has reduced motility. We identified EhCoactosin, an actin-binding protein not previously known to be phosphoregulated, as one of the differentially phosphorylated proteins in E. histolytica and demonstrated that EhCoactosin phosphorylation functions in control of cell membrane dynamics and amoebic motility. This and the additional differentially phosphorylated proteins reported lay the groundwork for identifying kinases and phosphatases that regulate tissue invasiveness.

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