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Seminars in Cancer Biology Feb 2008Increased motile activity, increased rate of cell proliferation and removal of growth inhibiting cell-cell contacts are hallmarks of tumorigenesis. Activation of cell... (Review)
Review
Increased motile activity, increased rate of cell proliferation and removal of growth inhibiting cell-cell contacts are hallmarks of tumorigenesis. Activation of cell motility and migration is caused by activation of receptors, turning on the growth cycle. Increased expression of metalloproteinases, breaking cell:cell contacts and organ confines, allows the spread of malignant cancer cells to other sites in the organism. It has become increasingly clear that most transmembrane proteins (growth factor receptors, adhesion proteins and ion channels) are either permanently or transiently associated with the sub-membraneous system of actin microfilaments (MF), whose force generating capacity they control. Although there has been great progress in our understanding of the physiological importance of the MF-system, as will be exemplified in this issue of SCB, many aspects of actin microfilament formation and its regulation are still unclear. Redox control of the actin (MF)-system in cell motility and migration and its perturbations in pathophysiology, including cancer, is an emerging field of research.
Topics: Actin Cytoskeleton; Actins; Animals; Cell Movement; Focal Adhesions; Humans; Hydrogen Peroxide; Membrane Proteins; Microfilament Proteins; Neoplasms; Phosphatidylinositols; Pseudopodia
PubMed: 18024149
DOI: 10.1016/j.semcancer.2007.10.002 -
Journal of Plant Research Mar 2017ACTIN DEPOLYMERIZING FACTOR (ADF) is a conserved protein among eukaryotes. The main function of ADF is the severing and depolymerizing filamentous actin (F-actin), thus... (Review)
Review
ACTIN DEPOLYMERIZING FACTOR (ADF) is a conserved protein among eukaryotes. The main function of ADF is the severing and depolymerizing filamentous actin (F-actin), thus regulating F-actin organization and dynamics and contributing to growth and development of the organisms. Mammalian genomes contain only a few ADF genes, whereas angiosperm plants have acquired an expanding number of ADFs, resulting in the differentiation of physiological functions. Recent studies have revealed functions of ADFs in plant growth and development, and various abiotic and biotic stress responses. In biotic stress responses, ADFs are involved in both susceptibility and resistance, depending on the pathogens. Furthermore, recent studies have highlighted a new role of ADF in the nucleus, possibly in the regulation of gene expression. In this review, I will summarize the current status of plant ADF research and discuss future research directions.
Topics: Actin Cytoskeleton; Destrin; Plant Proteins; Plants
PubMed: 28044231
DOI: 10.1007/s10265-016-0899-8 -
Proceedings of the National Academy of... Jul 2019The tracheary system of plant leaves is composed of a cellulose skeleton with diverse hierarchical structures. It is built of polygonally bent helical microfilaments of...
The tracheary system of plant leaves is composed of a cellulose skeleton with diverse hierarchical structures. It is built of polygonally bent helical microfilaments of cellulose-based nanostructures coated by different layers, which provide them high compression resistance, elasticity, and roughness. Their function includes the transport of water and nutrients from the roots to the leaves. Unveiling details about local interactions of tracheary elements with surrounding material, which varies between plants due to adaptation to different environments, is crucial for understanding ascending fluid transport and for tracheary mechanical strength relevant to potential applications. Here we show that plant tracheary microfilaments, collected from and leaves, have different surface morphologies, revealed by nematic liquid crystal droplets. This results in diverse interactions among microfilaments and with the environment; the differences translate to diverse mechanical properties of entangled microfilaments and their potential applications. The presented study also introduces routes for accurate characterization of plants' microfilaments.
Topics: Actin Cytoskeleton; Amaryllidaceae; Biomechanical Phenomena; Nanostructures; Ornithogalum; Plant Leaves; Plants; Xylem
PubMed: 31196953
DOI: 10.1073/pnas.1901118116 -
Current Opinion in Cell Biology Feb 1994The cortical actin cytoskeleton participates in various membrane-based processes which necessitate a large amount of plasticity in the molecular components involved in... (Comparative Study)
Comparative Study Review
The cortical actin cytoskeleton participates in various membrane-based processes which necessitate a large amount of plasticity in the molecular components involved in these interactions. A family of proteins homologous to band 4.1 is involved in the reorganization of the actin cytoskeleton in response to various stimuli, and probably plays a role in transmembrane signalling. This family includes tyrosine phosphatases, substrates of tyrosine kinases and a candidate for a tumor-suppressor gene.
Topics: Actin Cytoskeleton; Animals; Blood Proteins; Cell Membrane; Cytoskeletal Proteins; Cytoskeleton; Erythrocyte Membrane; Humans; Membrane Proteins; Microfilament Proteins; Neuropeptides; Phosphoproteins; Protein Structure, Secondary; Proteins
PubMed: 8167019
DOI: 10.1016/0955-0674(94)90127-9 -
Current Opinion in Plant Biology Dec 2007Actin microfilaments are highly organized and essential intracellular components of organelle movement and cell morphogenesis in plants. The organization of these... (Review)
Review
Actin microfilaments are highly organized and essential intracellular components of organelle movement and cell morphogenesis in plants. The organization of these microfilaments undergoes dynamic changes during cell division, elongation, and differentiation. Recent live-cell imaging of plant actin microfilaments has revealed their native organization and remarkable dynamics. In addition, characterization of plant actin side-binding proteins has progressed rapidly by genetic, biochemical, and bioinformatic approaches. The gathering and integration of microscopy-based information from actin microfilament dynamics and the molecular identification of actin side-binding proteins have provided considerable insights into actin microfilament-dependent events and actin microfilament organization in plants.
Topics: Actin Cytoskeleton; Arabidopsis; Arabidopsis Proteins; Chloroplast Proteins; Galactosyltransferases; Green Fluorescent Proteins; Membrane Glycoproteins; Microfilament Proteins; Myosins
PubMed: 17936064
DOI: 10.1016/j.pbi.2007.08.012 -
Biomolecular Concepts Dec 2016Matrix metalloproteinases (MMPs) are implicated in many physiological and pathological processes, including contraction, migration, differentiation, and proliferation.... (Review)
Review
Matrix metalloproteinases (MMPs) are implicated in many physiological and pathological processes, including contraction, migration, differentiation, and proliferation. These processes all involve cell phenotype changes, known to be accompanied by reorganization of actin cytoskeleton. Growing evidence indicates a correlation between MMP activity and the dynamics of actin system, suggesting their mutual regulation. Here, data on the influence of MMPs on the actin microfilament system, on the one hand, and the dependence of MMP expression and activation on the organization of actin structures, on the other hand, are reviewed. The different mechanisms of putative actin-MMP regulation are discussed.
Topics: Actin Cytoskeleton; Actins; Cell Differentiation; Cell Movement; Cell Proliferation; Enzyme Activation; Gene Expression Regulation; Humans; Matrix Metalloproteinases; Protein Binding
PubMed: 27763882
DOI: 10.1515/bmc-2016-0022 -
IUBMB Life May 2012Parasites from the phylum Apicomplexa are responsible for several major diseases of man, including malaria and toxoplasmosis. These highly motile protozoa use a... (Review)
Review
Parasites from the phylum Apicomplexa are responsible for several major diseases of man, including malaria and toxoplasmosis. These highly motile protozoa use a conserved actomyosin-based mode of movement to power tissue traversal and host cell invasion. The mode termed as 'gliding motility' relies on the dynamic turnover of actin, whose polymerisation state is controlled by a markedly limited number of identifiable regulators when compared with other eukaryotic cells. Recent studies of apicomplexan actin regulator structure-in particular those of the core triad of monomer-binding proteins, actin-depolymerising factor/cofilin, cyclase-associated protein/Srv2, and profilin-have provided new insights into possible mechanisms of actin regulation in parasite cells, highlighting divergent structural features and functions to regulators from other cellular systems. Furthermore, the unusual nature of apicomplexan actin itself is increasingly coming into the spotlight. Here, we review recent advances in understanding of the structure and function of actin and its regulators in apicomplexan parasites. In particular we explore the paradox between there being an abundance of unpolymerised actin, its having a seemingly increased potential to form filaments relative to vertebrate actin, and the apparent lack of visible, stable filaments in parasite cells.
Topics: Actin Cytoskeleton; Animals; Apicomplexa; Humans; Microfilament Proteins; Protein Binding; Protein Structure, Quaternary; Protozoan Proteins
PubMed: 22454107
DOI: 10.1002/iub.1014 -
Brain Research Bulletin Jul 2019Intracellular mechanical tension plays a vital role in maintaining neuronal function and is generated steerablely by motor proteins along microfilaments (MFs) and...
Intracellular mechanical tension plays a vital role in maintaining neuronal function and is generated steerablely by motor proteins along microfilaments (MFs) and microtubules (MTs). To explore the interaction between these subcellular tensions and elucidate their underlying mechanisms, we constructed MF- and MT-dependent tension probes using the Förster resonance energy transfer technique. Hypotonic stress activated MF and MT tensions in calcium-dependent manner, which antagonized outward expansion of cells synergistically; conversely, hypertonic stress attenuated MF and MT tensions in a calcium-independent manner and their interaction is antagonistical. In response to ischemia/hypoxia-related factors, glutamic acid upregulated MF and MT tensions synergistically, similarly to calcium signaling. Energy depletion elicited by ammonium ions increased MT tension, but not MF tension. Oxygen free radical stimulus had no effect on MT and MT tensions. However, MT tension was involved in the antagonism of MF tension in response to energy depletion and oxygen free radicals. Our findings suggest that intracellular MF and MT tensions can interact synergistically or antagonistically in neuronal cells, which is indispensable in ischemia/hypoxia -induced neuron dysfunction.
Topics: Actin Cytoskeleton; Animals; Biomechanical Phenomena; Calcium; Calcium Signaling; Cytoskeleton; Fluorescence Resonance Energy Transfer; Hypoxia; Microtubules; Neurons; Osmotic Pressure; PC12 Cells; Rats
PubMed: 31009699
DOI: 10.1016/j.brainresbull.2019.04.007 -
Kidney International Oct 1992Experimental ischemic acute renal failure results in disruption of proximal tubule apical membranes. Previous work utilizing immunofluorescence with an anti-actin...
Experimental ischemic acute renal failure results in disruption of proximal tubule apical membranes. Previous work utilizing immunofluorescence with an anti-actin antibody has demonstrated that the apical cytoskeleton of proximal tubule cells is disrupted during ischemic injury. In this study, using rhodamine-phalloidin which stains only filamentous actin, we demonstrate that graded durations of ischemia resulted in progressive disruption of proximal tubule apical microfilaments. Quantification using spectrofluorometry showed that 5, 15 and 50 minutes of ischemia resulted in 32.8 +/- 4%, 48.8 +/- 2.5%, and 58.4 +/- 2.6% decreases in apical F-actin relative to controls. Ischemia did not qualitatively affect either glomerular or distal tubule F-actin structure, though there were nonprogressive increases in glomerular fluorescence. In summary, rhodamine-phalloidin staining can be used to qualitatively and quantitatively assess proximal tubule microfilaments in vivo. We conclude that ischemia results in very early loss of proximal tubule apical microfilaments, with the majority of F-actin loss occurring within five minutes.
Topics: Actin Cytoskeleton; Actins; Adenosine Triphosphate; Animals; Fluorescent Antibody Technique; Ischemia; Kidney Tubules, Proximal; Male; Rats; Rats, Sprague-Dawley
PubMed: 1453583
DOI: 10.1038/ki.1992.366 -
Biochemical Pharmacology Aug 2023Cellular actin dynamic is controlled by a plethora of actin binding proteins (ABPs), including actin nucleating, bundling, cross-linking, capping, and severing proteins.... (Review)
Review
Cellular actin dynamic is controlled by a plethora of actin binding proteins (ABPs), including actin nucleating, bundling, cross-linking, capping, and severing proteins. In this review, regulation of actin dynamics by ABPs will be introduced, and the role of the F-actin severing protein cofilin-1 and the F-actin bundling protein L-plastin in actin dynamics discussed in more detail. Since up-regulation of these proteins in different kinds of cancers is associated with malignant progression of cancer cells, we suggest the cryogenic electron microscopy (Cryo-EM) structure of F- actin with the respective ABP as template for in silico drug design to specifically disrupt the interaction of these ABPs with F-actin.
Topics: Actins; Cryoelectron Microscopy; Microfilament Proteins; Actin Cytoskeleton; Drug Discovery; Protein Binding
PubMed: 37399949
DOI: 10.1016/j.bcp.2023.115680