Actin polymerization and filament. Medical search. Frequent questions

This research led to the discovery of two important cellular proteins, filamin and gelsolin, that regulate the assembly of actin. (wikipedia.org)
Bin/Amphiphysin/Rvs (BAR) proteins are peripheralmembrane proteins (PMP) and play an important role in sculpturingmembranes and in the regulation of actin dynamics. (kth.se)
Thisimplies that BIN1 rather bundles actin than decorates single filaments.Third, we explored a strategy to purify an aggregation prone BAR protein.Aggregation is a property common in Peripheral Membrane Proteins. (kth.se)
Chapter 1 provides an overview of these pathways including the key steps of DSB repair, the regulation of actin nucleation, and the proteins involved in chromatin mobility. (columbia.edu)
A major modulator of actin filament disassembly is the actin-depolymerization factor/cofilin family of proteins (hereafter referred to as cofilin). (rupress.org)
These small highly conserved actin-binding proteins are essential regulators of actin dynamics in living cells. (rupress.org)
Severing increases the number of actin filament pointed ends and, in conjunction with capping of barbed ends by capping proteins, stimulates filament disassembly ( Andrianantoandro and Pollard, 2006 ). (rupress.org)
Rho proteins promote reorganization of the actin cytoskeleton and regulate cell shape, attachment, and motility. (cancerindex.org)
Conserved proteins drive clathrin-mediated endocytosis (CME), which universally involves a burst of actin assembly. (biorxiv.org)
To elucidate the mechanism of actin disassembly, we characterized molecular kinetics of the major filament end-binding proteins Arp2/3 complex and capping protein (CP) using single-molecule speckle microscopy. (silverchair.com)
The contractile ring is made up of structural proteins, including actin filaments and myosin II filaments. (jove.com)
These dual functions provide an intriguing model of how membrane proteins can integrate distinct mechanisms to fine-tune local actin dynamics. (stanford.edu)
In this study, using direct visualization of single actin filament elongation, we show that actin polymerization kinetics at both filament ends are strongly influenced by the binding of proteins to the lateral filament surface. (cipsm.de)
Specific members of the Myosin superfamily of motor proteins are known to transport cargo along actin filaments. (mechanobio.info)
The filamin family of proteins bind to both actin and a number of signaling molecules including Rho GTPases. (mechanobio.info)
and proteins that interact with members of the Arp2/3 complex and hence the actin cytoskeleton (Table 1 ). (biomedcentral.com)
Proteins that regulate actin turnover are also key to cell movement. (ibiology.org)
Studies of EPEC and EHEC O157 show that these pathogens trigger different actin polymerization pathways respectively involving Tir cytoskeleton coupling proteins ( tccP or tccP2 ) ( 5 ). (cdc.gov)

Regulation of actin dynamics and analysis of genomic influences on actin function. (upstate.edu)
Actin Cytoskeletal Dynamics in the leukocyte inflammatory phenotype. (upstate.edu)
The growth cone is the site of axon extension, and it is characterized by a complex morphology wholly dependent on the actin filaments that underlie filopodia and lamellipodia formation and dynamics ( Dent and Gertler, 2003 ). (jneurosci.org)
Synaptic stimulation rapidly changes the actin dynamics and many actin regulators have been shown to play roles in neuron functionality. (nih.gov)
These three methods complement each other, each providing additional information about actin dynamics and organization in dendritic spines. (nih.gov)
and consequently membrane deformation.Second, we clarified BIN1's role in actin dynamics. (kth.se)
The dynamics of the actin-network enable the locomotion of cells, for example during development or wound closure, but also that of spreading cancer cells. (scitechdaily.com)
In this study, we analyzed the dynamics of fluorescently tagged cofilin and the role of cofilin-mediated actin turnover during endocytosis in Saccharomyces cerevisiae . (rupress.org)
However, the role of actin filament disassembly (a key step in actin dynamics) during actin-mediated endocytosis is less clear. (rupress.org)
Cofilin and its role in actin dynamics have been studied extensively in vitro. (rupress.org)
CP dissociates slower from actin stress fibers than from the lamellipodial actin network, suggesting that CP dissociation correlates with actin filament dynamics. (silverchair.com)
Actin filament dynamics govern many key physiological processes from cell motility to tissue morphogenesis. (cipsm.de)
A central feature of actin dynamics is the capacity of filaments to polymerize and depolymerize at their ends in response to cellular conditions. (cipsm.de)
Tuning elongation kinetics by exploiting the malleability of the filament structure may be a ubiquitous mechanism to generate a rich variety of cellular actin dynamics. (cipsm.de)
We addressed this by developing a computational model in which polymerization of actin filaments against a deformable membrane and variable adhesion dynamics support edge motion. (mtu.edu)

The interlaced structure of the cell cytoskeleton, constituted by actin and intermediate filaments and microtubules which continuously change their spatial organization and pre-stresses through polymerization/depolymerization, seems to steer migration, adhesion and cell division by obeying the tensegrity construct. (arxiv.org)
Actin forms the dendritic nucleation network and undergoes rapid polymerization-depolymerization cycles in lamellipodia. (silverchair.com)
Binding to the barbed end requires ICD dimerization and inhibits both actin polymerization and depolymerization, resembling the actin capping protein CapZ. (stanford.edu)

Nucleation, the rate-limiting step, is stimulated by a complex of actin-related protein Arp2/3 and WASp. (medscape.com)
The Arp2/3 complex generates propulsive forces by nucleating a highly branched network of actin filaments. (columbia.edu)
Using Xenopus laevis cell-free extracts and mammalian cells, we show that actin nucleation machinery (WASP, Arp2/3, and actin) is recruited to damaged chromatin undergoing HDR. (columbia.edu)
In this complex, the claudin-like transmembrane protein HPO-30 recruits the WAVE regulatory complex (WRC) to dendrite branching sites, stimulating the Arp2/3 complex to polymerize actin. (stanford.edu)

Next, gelsolin (activated by Ca ++ ) severs actin filaments to create barbed ends, but then must be uncapped from the filament by phosphatidylinositol 4,5-bisphosphonate and Rac to proceed with polymerization. (medscape.com)
This binding induces a twist in the filament, accelerates the release of Pi from ADP-Pi subunits, and severs actin filaments ( Pollard and Borisy, 2003 ). (rupress.org)

CryoEM reveals that themuscular BIN1 isoform does not bind to single actin filaments, althoughBIN1 can be co-sedimented with actin after polymerization of actin. (kth.se)

Latrunculin A disturbs Red Blood Cell actin filament assembly/disassembly. (agscientific.com)
In living cells, cofilin is not necessary for actin assembly on endocytic membranes but is recruited to molecularly aged adenosine diphosphate actin filaments and is necessary for their rapid disassembly. (rupress.org)
Genetic and biochemical analysis of a conditional allele of cofilin showed that the actin filament disassembly activity of cofilin is essential for fluid-phase endocytosis ( Lappalainen and Drubin, 1997 ). (rupress.org)
A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of cytoskeletal structures comprising actin filaments. (systemsbiology.net)

Formation of axonal F-actin bundles was independent of myosin II, but partially required RhoA-kinase activity. (biologists.com)
Collectively, these observations suggest that guidance cues cause axon retraction through the coordinated activation of myosin II and the formation of intra-axonal F-actin bundles for myosin-II-based force generation. (biologists.com)
Myosin II interacts with F-actin to generate contractile forces that result in axon retraction. (biologists.com)
how can myosin II drive axon retraction if the major source of the required substratum for force generation, growth cone F-actin, has been depleted? (biologists.com)
In combination with myosin motors, actin aids in transport by providing the roads and pathways for cellular cargo[ 13 ]. (biorxiv.org)
RhoA activity results in the assembly of myosin II and anti-parallel actin filaments into the structure of the contractile ring. (jove.com)
Here, myosin filaments move toward the plus end of adjacent antiparallel actin filaments. (jove.com)
Myosin-X step size corresponds to a single twist of the actin filament helix. (mechanobio.info)

The retrograde flow of microtubules oriented perpendicular to the leading edge in the lamellipodium is coupled to the movement of immediately adjacent lamellum f-actin speckles. (ucsd.edu)
The cytoskeleton is typically divided into three distinct components: microtubules, intermediate filaments and actin[ 4 , 5 ]. (biorxiv.org)
Unlike the globular units of microtubules and actin filaments, intermediate filaments are themselves constructed from filamentous sub-units, and confer strength as well as stress resistance to the cell[ 10 ]. (biorxiv.org)
Even though rough calculations lead to estimate discrepancies when comparing axial stiffness of actin filaments and microtubules and recent works have shown bent microtubules, no one has yet tried to remove the hypothesis of rigid struts in tensegrities when used to idealize the cytoskeleton mechanics. (arxiv.org)

Includes processes that control the spatial distribution of actin filaments, such as organizing filaments into meshworks, bundles, or other structures, as by cross-linking. (systemsbiology.net)
In all systems, these GTPases are best known for their effects on the polymerization and distribution of actin in the cell cortex [ 1 ]. (biomedcentral.com)

By regulating filamentous actin, Cdc42 and Rac exert a profound effect on cell shape, polarity, migration, cell:cell and cell:matrix adhesion, protein traffic, and cytokinesis. (biomedcentral.com)
Mapping synaptic transmission between identified neurons, they usually allow to record only one caused lysis to occur in some cases (S2B Fig and S1 Text) exhibit similar PCC trends, suggesting that DCP1 overexpression in naive cultures does not affect the formation of filamentous actin polymerisation. (storiedellaltromondo.com)

Furthermore, semaphorin 3A promotes the formation of intra-axonal F-actin bundles in concert with the loss of F-actin in growth cone lamellipodia and filopodia. (biologists.com)
The transport of components along filopodial shafts is crucial to the continued growth of actin filaments and the formation of adhesions at the tips of filopodia. (mechanobio.info)

Finally, actin filaments, also known as microfilaments, are the narrowest components of the cytoskeleton and are constructed from globular actin sub-units (G-actin) that assemble to form a helical structure 5-7nm in diameter[ 12 ]. (biorxiv.org)
Actin microfilaments are present as both individual filaments and bundled into thicker filaments, and play a key role in plant cell growth and internal transport[ 14 ]. (biorxiv.org)

Under conditions of suppressed oxidative phosphorylation and glycolysis actin turnover in developing neurons consumes ∼50% of the available ATP ( Bernstein and Bamburg, 2003 ), indicating that actin filament turnover is a major bioenergetic drain. (jneurosci.org)
Instead, to know how tightly actin filaments are bundled together, and how fast the filaments turnover, we need to use advanced microscopy techniques, such as fluorescence recovery after photobleaching (FRAP), photoactivatable green fluorescent protein (PAGFP) fluorescence decay and fluorescence anisotropy. (nih.gov)
Cofilin is the major mediator of actin filament turnover in vivo. (rupress.org)

In a certain parameter range of neutral pressure, power and magnetic field, a regime of individual filaments with rotating spiral arms has been identified by visible imaging from the top of the machine. (troy.edu)

The actin cytoskeleton is responsible for cellular functions such as growth, endocytosis, exocytosis, and cytokinesis. (medscape.com)
In contrast to budding yeast, WASP-mediated actin nucleation activity plays an essential role in fission yeast endocytosis. (biorxiv.org)

During the last decade, numerous studies have demonstrated that the actin cytoskeleton plays a pivotal role in the control of dendritic spine shape. (nih.gov)
Reorganization of the actin cytoskeleton plays crucial roles in many cellular functions, including morphology, motility, and adhesion. (biomedcentral.com)

We report here our biochemical and structural analysis of this interaction, revealing that the intracellular domain (ICD) of HPO-30 is intrinsically disordered and employs two distinct mechanisms to regulate the actin cytoskeleton. (stanford.edu)
Pospich S, Kumpula EP, von der Ecken J, Vahokoski J, Kursula I & Raunser S (2017) Near-atomic structure of jasplakinolide-stabilized malaria parasite F-actin reveals the structural basis of filament instability. (uib.no)

We validate the method in U2OS cell line where the actin structures can be clearly distinguished and apply to analyze how actin filament organization in dendritic spines changes during neuronal maturation. (nih.gov)
In cells, F-actin assumes specific types of organization depending on its functions. (biologists.com)

The WAVE regulatory complex (WRC) drives the polymerisation of actin filaments located beneath the plasma membrane to generate lamellipodia that are pivotal to cell architecture and movement. (biodiversityhotspot.org)

Defects in cofilin function alter the morphology of actin networks in vivo and reduce the rate of actin flux through actin networks. (rupress.org)

The intrinsically disordered cytoplasmic tail of a dendrite branching receptor uses two distinct mechanisms to regulate the actin cytoskeleton. (stanford.edu)

However, the molecular mechanism of cofilin recruitment to actin networks during dynamic actin-mediated processes in living cells and cofilin's precise in vivo functions have not been determined. (rupress.org)
Genetics and live-cell imaging revealed core CME spatiodynamic similarities between the two yeasts, though two-zone actin assembly is a fission yeast-specific mechanism, which is not essential for CME. (biorxiv.org)
A two-step actin polymerization mechanism drives dendrite branching. (stanford.edu)
Our model showed that adhesions' control of protrusion persistence originates from the Brownian ratchet mechanism for actin filament polymerization. (mtu.edu)
We propose a mechanism for cell edge protrusion in which adhesion strength regulates actin filament polymerization to control the periods of leading edge protrusion. (mtu.edu)

FMNL2 (green) induces the polymerization of actin filaments (white) at the vesicle, propelling it forward. (scitechdaily.com)

2010 suggested that additional unknown factors are required to facilitate WRC-dependent actin polymerisation (Davidson and Insall 2011 We showed that active Rac1 was indeed insufficient for recruitment and activation of the WRC at the membrane in mammalian cell extract (Koronakis et al. (biodiversityhotspot.org)
Formed from polymerisation of discrete protein sub-units, the cytoskeleton connects to various organelles (including the nucleus) and the plasma membrane. (biorxiv.org)
The consequences of decreasing actin flux are manifested by decreased but not blocked endocytic internalization at the plasma membrane and defects in late steps of membrane trafficking to the vacuole. (rupress.org)
Previous studies on the highly branched Caenorhabditis elegans PVD sensory neuron identified a membrane co-receptor complex that links extracellular signals to intracellular actin remodeling machinery, promoting high-order dendrite branching. (stanford.edu)
Filamin forms a vital scaffolding adaptor and regulatory component that contributes to the mechanical stability of cells by linking the internal actin network with membrane receptors and mechanosensitive components. (mechanobio.info)
Actin polymerization against the membrane and adhesions control edge motion, but the exact mechanisms that determine protrusion period remain elusive. (mtu.edu)
With longer adhesion lifetime or increased adhesion density, the proportion of actin filaments tethered to the substrate increased, maintaining filaments against the cell membrane. (mtu.edu)
The reduced filament-membrane distance generated pushing force for high edge velocity, but limited further polymerization needed for protrusion duration. (mtu.edu)

Considering filament polymerization requires ATP, inhibition of glycolysis results in a paradoxical increase in axonal actin filament levels. (jneurosci.org)

Consistent with previous reports, our model showed that actin polymerization and adhesion lifetime power protrusion velocity. (mtu.edu)

Reference: "Vesicle-Associated Actin Assembly by Formins Promotes TGFβ-Induced ANGPTL4 Trafficking, Secretion and Cell Invasion" by Dennis Frank, Jessica Christel Moussie, Svenja Ulferts, Lina Lorenzen, Carsten Schwan and Robert Grosse, 24 January 2023, Advanced Science . (scitechdaily.com)

Salamun J, Kallio JP, Daher W, Soldati-Favre D & Kursula I (2014) Structure of Toxoplasma gondii coronin - an actin-binding protein that relocalizes to the posterior pole of invasive parasites and contributes to invasion and egress. (uib.no)

Vahokoski J, Calder L, Lopez AJ, Molloy JE, Kursula I & Rosenthal PB (2022) High-resolution structures of malaria parasite actomyosin and actin filaments. (uib.no)

Cofilin binds preferentially to ADP-actin subunits within actin filaments. (rupress.org)
Second, HPO-30 ICD directly binds to the sides and barbed end of actin filaments. (stanford.edu)
Filamin binds all actin isoforms (e.g. (mechanobio.info)

Due to the small size of spines, it is difficult to detect changes in the actin structures in dendritic spines by conventional light microscopy imaging. (nih.gov)
Being able to extract spatial networks composed of one-dimensional structures, from road networks to sub-cellular biological filaments, is a recurring theme throughout many research areas. (biorxiv.org)

It was rapidly demonstrated that the toxins target the cytoskeleton and inhibit the actin polymerization by specifically sequestering the G-actin monomers with a high affinity [4] , unlike cytochalasin D that targets the actin filament [5] . (beilstein-journals.org)
Binding sites are represented by red and dark blue actin monomers. (mechanobio.info)

Actin is an ATPase and must be loaded with ATP to polymerize and subsequently hydrolyzes the ATP once incorporated into a filament. (jneurosci.org)

Actin filaments are part of the cell skeleton and essential for stability and motility. (scitechdaily.com)
Moreau CA, Quadt KA, Piirainen H, Kumar H, Bhargav SP, Strauss L, Tolja NH, Wade RC, Spatz JP, Kursula I & Frischknecht F (2020) Optical tweezers uncover a function of profilin in force generation during malaria parasite motility independent of actin binding. (uib.no)
Jacot D, Tosetti N, Pires IP, Stock J, Graindorge A, Hung YF, Han H, Tewari R, Kursula I & Soldati-Favre D (2016) An apicomplexan actin-binding protein serves as a connector and lipid sensor to coordinate motility and invasion. (uib.no)
Julie Theriot explains how the polymerization of actin into filaments drives cell motility. (ibiology.org)

Based on the microscopic observations and genetic analyses, the scientists conclude that the vesicles' movement is controlled by the formin-like molecule FMNL2 by initiating polymerization - i.e. elongation - of actin filaments directly at the vesicle. (scitechdaily.com)

Lartrunculin A inhibits actin polymerization. (agscientific.com)

2011 This led to our discovery that Arf family GTPases directly recruit and activate the WRC which is enhanced when Arf and Rac1 work together to trigger actin polymerisation. (biodiversityhotspot.org)
Genotoxic agents trigger actin polymerization in the nucleus. (columbia.edu)

Comparison of actin speckle microscopy with phalloidin staining. (ucsd.edu)
Part of the problem lies in the difficulty of extracting high-quality, three-dimensional, quantitative measures of actin network features from microscopy data. (biorxiv.org)

The precise coupling of f-actin and parallel MT movements occurrs in all four zones of f-actin dynamic behavior: the lamellipodium,lamellum, convergence zone, and cell body. (ucsd.edu)
At the leading edge and throughout the lamellipodium, f-actin s. (ucsd.edu)

F-actin is concentrated at the growth cone and sparse in the axon ( Letourneau, 1983 ). (biologists.com)
Importantly, repellent guidance cues cause growth cone collapse and depolymerize growth cone F-actin while promoting axon retraction ( Gallo and Letourneau, 2004 ). (biologists.com)

While Arf79F was predominantly found at the perinuclear Golgi apparatus Arf79F was also observed enriched at the actin-rich cell edge where it colocalised with the WRC component Sra1 (inset). (biodiversityhotspot.org)
Like endogenous Arf79F recombinant RFP-tagged Arf79F was also detected by immunoblotting with Arf1 antibody (supplementary material Fig. S2B) and was visualised at the cell edge where it colocalised with Sra1 and actin (insets) (Fig.?1B). (biodiversityhotspot.org)
Actin also plays a role in the transport of substances within the cell. (scitechdaily.com)
With fluorescent markers, the prometastatic factor ANGPTL4 is labeled in magenta, the molecule FMNL2 in green, and the actin cell skeleton in white. (scitechdaily.com)
We observed that ANGPTL4-loaded vesicles are conveyed to the periphery of the cell by means of dynamic and localized polymerization of actin filaments," says Grosse, who is a member of the Cluster of Excellence CIBSS - Centre for Integrative Biological Signalling Studies at the University of Freiburg. (scitechdaily.com)
The actin cytoskeleton is essential in eukaryotes, not least in the plant kingdom where it plays key roles in cell expansion, cell division, environmental responses and pathogen defence. (biorxiv.org)
Yet, the precise structure-function relationships of properties of the actin network in plants are still to be unravelled, including details of how the network configuration depends upon cell type, tissue type and developmental stage. (biorxiv.org)
To address this problem, we have developed DRAGoN, a novel image analysis algorithm that can automatically extract the actin network across a range of cell types, providing seventeen different quantitative measures that describe the network at a local level. (biorxiv.org)
Latrunculins are marine toxins used in cell biology to block actin polymerization. (beilstein-journals.org)

Conversely, RhoA-kinase activity was required to shut down F-actin polymerization underlying protrusive activity. (biologists.com)
I suggest that in the context of semaphorin 3A signaling, RhoA-kinase serves as a switch to change the function of the F-actin cytoskeleton from promoting protrusive activity to generating contractile forces. (biologists.com)

Bendes ÁÁ, Kursula P & Kursula I (2022) Structure and function of an atypical homodimeric actin capping protein from the malaria parasite. (uib.no)
Malaria parasite actin polymerization and filament structure. (storiedellaltromondo.com)

[ 3 ] The exact function of WASp is not fully elucidated, but it seems to function as a bridge between signaling and movement of the actin filaments in the cytoskeleton. (medscape.com)

Cdc42 and Rac - ancient, highly conserved, small GTPases - mediate extracellular signals, triggering changes in transcription and in the actin cytoskeleton. (biomedcentral.com)

Kumpula EP, Lopez AJ, Tajedin L, Han H & Kursula I (2019) Atomic view into Plasmodium actin polymerization, ATP hydrolysis, and fragmentation. (uib.no)

Accordingly, defects in the regulation of the actin cytoskeleton in neurons have been implicated in memory disorders. (nih.gov)

Using this algorithm, we then studied a number of cases in Arabidopsis thaliana , including several different tissues, a variety of actin-affected mutants, and cells responding to powdery mildew. (biorxiv.org)
In addition to these results, our algorithm is designed to be easily adaptable to other tissues, mutants and plants, and so will be a valuable asset for the study and future biological engineering of the actin cytoskeleton in globally-important crops. (biorxiv.org)

RhoA promotes localized actin filament polymerization which is necessary for the contractile ring formation. (jove.com)

[ 4 ] that interfere with the protein binding to Cdc42 and Rac GTPases, among other binding partners, most of which are involved in regulation of the actin cytoskeleton of lymphocytes. (medscape.com)

It is currently thought that filament kinetics can be described by a single rate constant for each end. (cipsm.de)

Anatomy36

Organisms16

Diseases1

Chemicals and Drugs133

Analytical, Diagnostic and Therapeutic Techniques and Equipment22

Phenomena and Processes44

Disciplines and Occupations1

Technology, Industry, Agriculture3

Information Science5

Health Care1

Proteins18

Dynamics15

Depolymerization3

Arp24

Severs actin filaments2

Single actin filaments1

Disassembly4

Myosin8

Microtubules4

Distribution of actin2

Filamentous2

Filopodia2

Microfilaments2

Turnover3

Individual filaments1

Endocytosis2

Cytoskeleton plays2

Structural2

Organization2

Lamellipodia1

Morphology1

Regulate1

Mechanism5

Induces1

Membrane8

Axonal1

Adhesion1

Assembly1

Toxoplasma1

Actomyosin1

Binds3

Structures2

Monomers2

Polymerize1

Motility4

Elongation1

Inhibits1

Trigger2

Microscopy2

Lamellipodium2

Growth cone2

Cell9

Kinase2

Malaria2

WASp1

Extracellular1

Plasmodium1

Neurons1

Mutants2

Formation1

Binding1

Kinetics1