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Cold Spring Harbor Perspectives in... Jan 2018The actin cytoskeleton-a collection of actin filaments with their accessory and regulatory proteins-is the primary force-generating machinery in the cell. It can produce... (Review)
Review
The actin cytoskeleton-a collection of actin filaments with their accessory and regulatory proteins-is the primary force-generating machinery in the cell. It can produce pushing (protrusive) forces through coordinated polymerization of multiple actin filaments or pulling (contractile) forces through sliding actin filaments along bipolar filaments of myosin II. Both force types are particularly important for whole-cell migration, but they also define and change the cell shape and mechanical properties of the cell surface, drive the intracellular motility and morphogenesis of membrane organelles, and allow cells to form adhesions with each other and with the extracellular matrix.
Topics: Actin Cytoskeleton; Actins; Animals; Biological Transport; Cell Movement; Humans; Morphogenesis; Muscle Contraction; Myosin Type II; Phagocytosis
PubMed: 29295889
DOI: 10.1101/cshperspect.a018267 -
Science (New York, N.Y.) Nov 2009The protein actin forms filaments that provide cells with mechanical support and driving forces for movement. Actin contributes to biological processes such as sensing... (Review)
Review
The protein actin forms filaments that provide cells with mechanical support and driving forces for movement. Actin contributes to biological processes such as sensing environmental forces, internalizing membrane vesicles, moving over surfaces, and dividing the cell in two. These cellular activities are complex; they depend on interactions of actin monomers and filaments with numerous other proteins. Here, we present a summary of the key questions in the field and suggest how those questions might be answered. Understanding actin-based biological phenomena will depend on identifying the participating molecules and defining their molecular mechanisms. Comparisons of quantitative measurements of reactions in live cells with computer simulations of mathematical models will also help generate meaningful insights.
Topics: Actin Cytoskeleton; Actins; Animals; Bacterial Physiological Phenomena; Cell Movement; Cell Shape; Cytokinesis; Cytoskeleton; Endocytosis; Organelles
PubMed: 19965462
DOI: 10.1126/science.1175862 -
Anatomical Record (Hoboken, N.J. : 2007) Dec 2018Microridges are highly distinctive "fingerprint"-patterned structures situated on the outer surface of superficial layer cells of the epithelium. An F-actin-based... (Review)
Review
Microridges are highly distinctive "fingerprint"-patterned structures situated on the outer surface of superficial layer cells of the epithelium. An F-actin-based cytoskeleton is the underlying core structural component of microridges. The basis for much of what is known about microridges has been provided by in vivo and in vitro fish epithelial systems. Nonetheless the microridge literature is quite small, especially when compared with other actin-based cellular structures such as those involved in cell motility. A PubMed search of the terms "Microridges" yields 261 citations from the mid-1970s to the writing of this review. "Microplicae," an alternative name for microridges, and "Actin Microridges" search terms give 204 and 8 references, respectively, in the same time period. By comparison a search of "Lamellipodia" over the same time period yields over 6,400 citations for this important motility structure while a search of the associated "filopodia" results in close to 7,300 articles. Despite the near-ubiquity of microridges in epithelia across species the study of these structures has clearly been neglected. In-depth analysis of microridge molecular composition is very limited while their function remains unclear. This review draws upon information derived from studies of fish as well as mammalian species to provide a more comprehensive view of these structures. The wide-spread distribution of these structures between species and various tissues indicate the microridges have important and common functions in healthy organisms. Conversely, disease conditions may show alterations in microridge structure and function and thus warrant further investigation. Anat Rec, 301:2037-2050, 2018. © 2018 Wiley Periodicals, Inc.
Topics: Actin Cytoskeleton; Actins; Animals; Epithelium; Humans
PubMed: 30414250
DOI: 10.1002/ar.23965 -
The EMBO Journal Apr 2021The identification of Tunneling Nanotubes (TNTs) and TNT-like structures signified a critical turning point in the field of cell-cell communication. With hypothesized... (Review)
Review
The identification of Tunneling Nanotubes (TNTs) and TNT-like structures signified a critical turning point in the field of cell-cell communication. With hypothesized roles in development and disease progression, TNTs' ability to transport biological cargo between distant cells has elevated these structures to a unique and privileged position among other mechanisms of intercellular communication. However, the field faces numerous challenges-some of the most pressing issues being the demonstration of TNTs in vivo and understanding how they form and function. Another stumbling block is represented by the vast disparity in structures classified as TNTs. In order to address this ambiguity, we propose a clear nomenclature and provide a comprehensive overview of the existing knowledge concerning TNTs. We also discuss their structure, formation-related pathways, biological function, as well as their proposed role in disease. Furthermore, we pinpoint gaps and dichotomies found across the field and highlight unexplored research avenues. Lastly, we review the methods employed to date and suggest the application of new technologies to better understand these elusive biological structures.
Topics: Actin Cytoskeleton; Animals; Cell Communication; Cell Surface Extensions; Humans; Nanotubes
PubMed: 33646572
DOI: 10.15252/embj.2020105789 -
Pediatric Nephrology (Berlin, Germany) Sep 2021The selectivity of the glomerular filter is established by physical, chemical, and signaling interplay among its three core constituents: glomerular endothelial cells,... (Review)
Review
The selectivity of the glomerular filter is established by physical, chemical, and signaling interplay among its three core constituents: glomerular endothelial cells, the glomerular basement membrane, and podocytes. Functional impairment or injury of any of these three components can lead to proteinuria. Podocytes are injured in many forms of human and experimental glomerular disease, including minimal change disease, focal segmental glomerulosclerosis, and diabetes mellitus. One of the earliest signs of podocyte injury is loss of their distinct structure, which is driven by dysregulated dynamics of the actin cytoskeleton. The status of the actin cytoskeleton in podocytes depends on a set of actin binding proteins, nucleators and inhibitors of actin polymerization, and regulatory GTPases. Mutations that alter protein function in each category have been implicated in glomerular diseases in humans and animal models. In addition, a growing body of studies suggest that pharmacological modifications of the actin cytoskeleton have the potential to become novel therapeutics for podocyte-dependent chronic kidney diseases. This review presents an overview of the essential proteins that establish actin cytoskeleton in podocytes and studies demonstrating the feasibility of drugging actin cytoskeleton in kidney diseases.
Topics: Actin Cytoskeleton; Animals; Humans; Podocytes
PubMed: 33188449
DOI: 10.1007/s00467-020-04812-z -
Current Biology : CB Aug 2014
Topics: Actin Cytoskeleton; Cell Biology; France; History, 20th Century; History, 21st Century; Molecular Biology; Morphogenesis; United States
PubMed: 25237695
DOI: 10.1016/j.cub.2014.06.007 -
FEBS Letters Nov 2018The actin cytoskeleton and Rho GTPase signaling to actin assembly are prime targets of bacterial and viral pathogens, simply because actin is involved in all motile and... (Review)
Review
The actin cytoskeleton and Rho GTPase signaling to actin assembly are prime targets of bacterial and viral pathogens, simply because actin is involved in all motile and membrane remodeling processes, such as phagocytosis, macropinocytosis, endocytosis, exocytosis, vesicular trafficking and membrane fusion events, motility, and last but not least, autophagy. This article aims at providing an overview of the most prominent pathogen-induced or -hijacked actin structures, and an outlook on how future research might uncover additional, equally sophisticated interactions.
Topics: Actin Cytoskeleton; Autophagy; Bacteria; Cell Membrane; Host-Pathogen Interactions; Humans; Signal Transduction; Virulence; Viruses
PubMed: 29935019
DOI: 10.1002/1873-3468.13173 -
FEMS Microbiology Reviews Mar 2014The actin cytoskeleton is a complex network of dynamic polymers, which plays an important role in various fundamental cellular processes, including maintenance of cell... (Review)
Review
The actin cytoskeleton is a complex network of dynamic polymers, which plays an important role in various fundamental cellular processes, including maintenance of cell shape, polarity, cell division, cell migration, endocytosis, vesicular trafficking, and mechanosensation. Precise spatiotemporal assembly and disassembly of actin structures is regulated by the coordinated activity of about 100 highly conserved accessory proteins, which nucleate, elongate, cross-link, and sever actin filaments. Both in vivo studies in a wide range of organisms from yeast to metazoans and in vitro studies of purified proteins have helped shape the current understanding of actin dynamics and function. Molecular genetics, genome-wide functional analysis, sophisticated real-time imaging, and ultrastructural studies in concert with biochemical analysis have made yeast an attractive model to understand the actin cytoskeleton, its molecular dynamics, and physiological function. Studies of the yeast actin cytoskeleton have contributed substantially in defining the universal mechanism regulating actin assembly and disassembly in eukaryotes. Here, we review some of the important insights generated by the study of actin cytoskeleton in two important yeast models the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe.
Topics: Actin Cytoskeleton; Cell Polarity; Cytokinesis; Endocytosis; Saccharomyces cerevisiae; Schizosaccharomyces
PubMed: 24467403
DOI: 10.1111/1574-6976.12064 -
Small GTPases 2021Cell invasion is associated with numerous patho-physiologic states including cell development and metastatic dissemination. This process couples the activation of cell... (Review)
Review
Cell invasion is associated with numerous patho-physiologic states including cell development and metastatic dissemination. This process couples the activation of cell motility with the capacity to degrade the extracellular matrix, thereby permitting cells to pass through basal membranes. Invasion is sustained by the actions of invadosomes, an ensemble of subcellular structures with high functional homology. Invadosomes are 3D acto-adhesive structures that can also mediate local extracellular matrix degradation through the controlled delivery of proteases. Intracellular RHO GTPases play a central role in the regulation of invadosomes where their complex interplay regulates multiple invadosome functions. This review aims to provide an overview of the synergistic activities of the small GTPases in invadosome biology. This broad-based review also reinforces the importance of the spatiotemporal regulation of small GTPases and the impact of this process on invadosome dynamics.
Topics: Actin Cytoskeleton; Animals; Cell Movement; Extracellular Matrix; Humans; Monomeric GTP-Binding Proteins; Podosomes
PubMed: 33487105
DOI: 10.1080/21541248.2021.1877081 -
Journal of Molecular and Cellular... May 2010Increased myofilament Ca(2+) sensitivity is a common attribute of many inherited and acquired cardiomyopathies that are associated with cardiac arrhythmias. Accumulating... (Review)
Review
Increased myofilament Ca(2+) sensitivity is a common attribute of many inherited and acquired cardiomyopathies that are associated with cardiac arrhythmias. Accumulating evidence supports the concept that increased myofilament Ca(2+) sensitivity is an independent risk factor for arrhythmias. This review describes and discusses potential underlying molecular and cellular mechanisms how myofilament Ca(2+) sensitivity affects cardiac excitation and leads to the generation of arrhythmias. Emphasized are downstream effects of increased myofilament Ca(2+) sensitivity: altered Ca(2+) buffering/handling, impaired energy metabolism and increased mechanical stretch, and how they may contribute to arrhythmogenesis.
Topics: Actin Cytoskeleton; Animals; Arrhythmias, Cardiac; Calcium; Disease Susceptibility; Humans; Myocardium; Signal Transduction; Stress, Mechanical
PubMed: 20097204
DOI: 10.1016/j.yjmcc.2010.01.011