Actin monomers. Medical search. Frequent questions

In budding yeast, the actin-binding protein Bud6 cooperates with formins Bni1 and Bnr1 to catalyze the assembly of actin filaments. (nih.gov)
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)
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)
Treadmilling of actin filaments via Brownian dynamics simulations. (mpg.de)
Self-assembly of actin monomers into long filaments: brownian dynamics simulations. (mpg.de)
[ 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)
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)
Pre-formed actin filaments (PAFs) are supplied as a lyophilized powder. (cytoskeleton.com)
These stringently quality controlled filaments provide highly reliable and reproducible results in assays that require actin filament substrates. (cytoskeleton.com)
Filopodia are finger-like projections supported by a cytoskeleton of bundled actin filaments ( Gallo and Letourneau, 2000 ). (jneurosci.org)
These domains cross-link actin filaments into bundles and networks. (embl.de)
Interestingly, FH2 domains induce unbranched actin filaments unlike the Arp 2/3 complex which initiates branched actin filaments. (mshri.on.ca)
Eukaryotic cells rely on de novo nucleation mechanisms to generate actin filaments in order to elicit spatial and temporal remodeling of their actin cytoskeleton. (biomedcentral.com)
During differentiation, upon exit from stem-cell-containing crypts, enterocytes build thousands of microvilli, each supported by a parallel bundle of actin filaments several microns in length. (vanderbilt.edu)
Intracellular L. monocytogenes replicate in the cytoplasm of host cells and induce the polymerization of host actin filaments at the bacterial surface. (silverchair.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)
Cofilin binds preferentially to ADP-actin subunits within actin filaments. (rupress.org)
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)
The molecular determinants of cofilin recruitment to actin filaments in vivo have not been fully investigated. (rupress.org)
This localization was found to be unaffected by manipulations that were expected to change polymerization rates at the leading edge, which should alter the relative abundance of ATP-, ADP-Pi-, and ADP-actin subunits within the filaments. (rupress.org)
Phalloidin binds to actin filaments much more tightly than to actin monomers, leading to a decrease in the rate constant for the dissociation of actin subunits from filament ends, essentially stabilizing actin filaments through the prevention of filament depolymerization. (aatbio.com)
The property of phalloidin is a useful tool for investigating the distribution of F-actin in cells by labeling phalloidin with fluorescent analogs and using them to stain actin filaments for light microscopy. (aatbio.com)
Fluorescent derivatives of phalloidin have turned out to be enormously useful in localizing actin filaments in living or fixed cells as well as for visualizing individual actin filaments in vitro. (aatbio.com)
Tpm3.1/2 forms a co-polymer with mitotic cortical actin filaments, and its inhibition prevents rescue of multipolar spindles induced by anti-microtubule chemotherapeutics. (bvsalud.org)
Central to this mechanism is the dependence of NM2A on Tpm3.1/2 to produce the functional engagement of actin filaments responsible for cortical tension. (bvsalud.org)

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)
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)
In addition, this problem is by far the most acute for actin, the narrowest element of the cytoskeleton, which is ubiquitous throughout eukaryotic cells. (biorxiv.org)
[ 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)
The actin cytoskeleton is responsible for cellular functions such as growth, endocytosis, exocytosis, and cytokinesis. (medscape.com)
Upregulation of Tβ 4 by cDNA-mediated transfection was found to cause actin depolymerization in fibroblast cells ( 1 ), which demonstrated that the modulation of Tβ 4 affected the polymerization state of actin cytoskeleton, as well as other cell processes associated with the organization of actin cytoskeleton, such as cell migration. (spandidos-publications.com)
The Rho family of GTPases regulate the actin cytoskeleton. (jneurosci.org)
We conclude that clusters of three integrin-binding ligands are necessary and sufficient for coupling to and translocating with the actin cytoskeleton. (biologists.com)
These links are used in cell motility as the actin cytoskeleton generates force pulling the integrin and attached matrix molecules towards the cell center. (biologists.com)
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)
The actin cytoskeleton is a complex structure that performs a wide range of cellular functions. (edu.au)
In particular, 1) the structure of actin was resolved from crystals in the absence of cocrystallized actin binding proteins (ABPs), 2) the prokaryotic ancestral gene of actin was crystallized and its function as a bacterial cytoskeleton was revealed, and 3) the structure of the Arp2/3 complex was described for the first time. (edu.au)
Encodes profilin3, a low-molecular weight, actin monomer-binding protein that regulates the organization of actin cytoskeleton. (or.jp)

AKF99 is also an excellent substrate for detecting actin binding proteins, see Fig. 2. (cytoskeleton.com)
This unambiguously demonstrates that the overall structure of monomeric actin is not significantly affected by a multitude of actin-binding proteins and toxins. (rcsb.org)
Actin binding domains present in duplicate at the N-termini of spectrin-like proteins (including dystrophin, alpha-actinin). (embl.de)
A number of actin-binding proteins, including spectrin, alpha-actinin and fimbrin, contain a 250 amino acid stretch called the actin binding domain (ABD). (embl.de)
In addition, the CH domain occurs also in a number of proteins not known to bind actin, a notable example being the vav protooncogene. (embl.de)
Gelation factor (ABP120) is one of the principal actin-cross-linking proteins of Dictyostelium discoideum. (embl.de)
Formins are multidomain proteins defined by a conserved FH2 (formin homology 2) domain with actin nucleation activity preceded by a proline-rich FH1 (formin homology 1) domain. (biomedcentral.com)
In vitro, the FH2 domain competes with barbed-end capping proteins and is necessary and sufficient to nucleate actin polymerization, but the FH1 domain, which interacts with profilin-actin, funnels actin to the nucleation vicinity and confers full activity to the molecule [ 1 ]. (biomedcentral.com)
Trisoxazole macrolide toxins mimic the binding of actin-capping proteins to actin. (expasy.org)
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)
The filamin family of proteins bind to both actin and a number of signaling molecules including Rho GTPases. (mechanobio.info)

Nucleation, the rate-limiting step, is stimulated by a complex of actin-related protein Arp2/3 and WASp. (medscape.com)
PAFs have been prepared from rabbit skeletal muscle actin protein that is greater than 99% pure (Cat. (cytoskeleton.com)
Effects on brush border growth were rescued by treatment with the G-actin sequestering drug, latrunculin A. G-actin binding protein, profilin-1, colocalized in the terminal web with G-actin, and knockdown of this factor compromised brush border growth in a concentration-dependent manner. (vanderbilt.edu)
The Listeria monocytogenes ActA protein mediates actin-based motility by recruiting and stimulating the Arp2/3 complex. (silverchair.com)
Actin is the most abundant cytoskeletal protein, accounting for 20% of the total protein content in all eukaryotic cells, especially muscle cells. (projectsparadise.com)

The nucleation-enhancing activity of Bud6 requires both a "core" domain that binds to the formin and a "flank" domain that binds monomeric actin. (nih.gov)
one binds in a groove at the barbed end of the actin monomer in a manner closely resembling the helix of WH2 domains, a motif found in many actin nucleation factors. (nih.gov)
Filamin binds all actin isoforms (e.g. (mechanobio.info)
This red fluorescent phalloidin conjugate (equivalent to Alexa Fluor® 594-labeled phalloidin) selectively binds to F-actins. (aatbio.com)

To examine this possibility, we inhibited Arp2/3, the ubiquitous branched actin nucleator, to increase G-actin availability during brush border assembly. (vanderbilt.edu)
Furthermore, purified VASP enhances the actin-nucleating activity of wild-type ActA and the Arp2/3 complex while also reducing the frequency of actin branch formation. (silverchair.com)

Many of these are likely to help us understand and distinguish between the structural models of actin microfilaments. (edu.au)
When introduced into the cytoplasm at low concentrations, phalloidin recruits the less polymerized forms of cytoplasmic actin as well as filamin into stable 'islands' of aggregated actin polymers, yet it does not interfere with stress fibers, i.e. thick bundles of microfilaments. (aatbio.com)

it also led to a redistribution of F-actin from cortical lateral networks into the brush border. (vanderbilt.edu)
An unbiased screen of 150 small molecules that impact actin organization and 32 anti-mitotic drugs identified two molecular targets, Rho kinase (ROCK) and tropomyosin 3.1/2 (Tpm3.1/2), whose inhibition has the greatest impact on mitotic cortical tension. (bvsalud.org)

Polarized polymerization of actin propels the bacteria through the cytoplasm and into pseudopod-like structures that are engulfed by neighboring cells. (silverchair.com)

The ability of VASP to contribute to actin filament nucleation and to regulate actin filament architecture highlights the central role of VASP in actin-based motility. (silverchair.com)

Formins act as profilin-modulated processive actin nucleators conserved throughout a wide range of eukaryotes. (biomedcentral.com)
Thus, brush border assembly is limited by G-actin availability, and profilin-1 directs unallocated actin monomers into microvillar core bundles during enterocyte differentiation. (vanderbilt.edu)

In combination with myosin motors, actin aids in transport by providing the roads and pathways for cellular cargo[ 13 ]. (biorxiv.org)

Our analysis allows some preliminary insight into the functionality of Dictyostelium formins: all isoforms might display actin nucleation activity and, with the exception of ForI, might also be susceptible to autoinhibition and to regulation by Rho GTPases. (biomedcentral.com)

Mutational analysis verifies the importance of these Bud6-actin contacts for nucleation-enhancing activity. (nih.gov)

Cofilin and its role in actin dynamics have been studied extensively in vitro. (rupress.org)

Fluorescence microscopy showed that the trimer and pentamer bound strongly to the cell surface, and within 5 minutes were prominently localized to actin fiber bundles. (biologists.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)
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)

The approximately 400 amino acid FH2 domain promotes filamentous actin growth by catalyzing the nucleation of actin chains. (mshri.on.ca)

They have been shown to move cargoes such as vesicles along actin filament tracks. (cytoskeleton.com)

The Bud6 binding site on actin overlaps with that of the formin FH2 domain and is also incompatible with inter-subunit contacts in F-actin, suggesting that Bud6 interacts only transiently with actin monomers during filament nucleation. (nih.gov)

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)

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)

Latrunculins are marine toxins used in cell biology to block actin polymerization. (beilstein-journals.org)

Here, we provide genetic and biochemical evidence that vasodilator-stimulated phosphoprotein (VASP) recruitment by ActA can bypass defects in actin monomer-binding. (silverchair.com)

In contrast to the much more open conformation of the ECP-actin's nucleotide binding cleft in solution, the crystal structure of uncomplexed ECP-actin contains actin in a typical closed conformation similar to the complexed actin structures. (rcsb.org)

All actin crystal structures reported to date represent actin complexed or chemically modified with molecules that prevent its polymerization. (rcsb.org)

Beads coated with a low concentration (probably one complex per bead) of trimer or pentamer showed prolonged binding and rearward translocation, presumably with the translocating actin cytskeleton. (biologists.com)
Beads containing monomer or dimer showed only brief binding and diffusive movements. (biologists.com)

The invariance of actin crystal structures suggests that the salt and precipitants necessary for crystallization stabilize actin in only one of its possible conformations. (rcsb.org)

This lasso and post interface is thought to mediate actin binding. (mshri.on.ca)

Cofilin is the major mediator of actin filament turnover in vivo. (rupress.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)
These results suggest that cofilin-mediated actin filament flux is required for the multiple steps of endocytic trafficking. (rupress.org)

In addition, symmetry-related actin-actin contacts form a head to tail dimer that is strikingly similar to the longitudinal dimer predicted by the Holmes F-actin model, including a rotation of the monomers relative to each other not observed previously in actin crystal structures. (rcsb.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)

We also show a critical role for the actin regulator Tropomyosin 4 in the final steps of platelet formation in lung vasculature. (bvsalud.org)

Each single ABD, comprising two CH domains, is able to bind one actin monomer in the filament. (embl.de)
The N-terminal CH domain has the intrinsic ability to bind actin, albeit with lower affinity than the complete ABD, whereas the C-terminal CH bind actin extremely weakly or not at all. (embl.de)

Here, we describe the structure of the Bud6 flank domain in complex with actin. (nih.gov)

Thymosin β 4 (Tβ 4 ), an oligopeptide consisting of 43 amino acids, is known to sequester G-actin monomers. (spandidos-publications.com)

Moreover, phalloidin is found to inhibit the ATP hydrolysis activity of F-actin. (aatbio.com)

Anatomy19

Organisms8

Chemicals and Drugs103

Analytical, Diagnostic and Therapeutic Techniques and Equipment27

Phenomena and Processes47

Disciplines and Occupations2

Technology, Industry, Agriculture8

Information Science5

Health Care1

Filaments27

Cytoskeleton13

Proteins13

Protein5

Binds4

Arp22

Microfilaments2

Cortical2

Polymerization of actin1

Regulate1

Profilin2

Myosin1

Isoforms1

Nucleation-enhancin1

Vitro1

Bundles1

Endocytosis3

Filamentous1

Vesicles1

Interacts1

Processes1

Filamin1

Cell biology1

VASP1

Nucleotide1

Molecules1

Beads2

Stabilize1

Mediate1

Cofilin3

Structures1

Defects1

Regulator1

Bind2

Complex1

Amino1

Inhibit1