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The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms. It is composed of three main components: microfilaments, intermediate filaments, and microtubules, and these are all capable of rapid growth or disassembly depending on the cell's requirements.
Microfilaments, also called actin filaments, are protein filaments in the cytoplasm of eukaryotic cells that form part of the cytoskeleton. They are primarily composed of polymers of actin, but are modified by and interact with numerous other proteins in the cell. Microfilaments are usually about 7 nm in diameter and made up of two strands of actin. Microfilament functions include cytokinesis, amoeboid movement, cell motility, changes in cell shape, endocytosis and exocytosis, cell contractility, and mechanical stability. Microfilaments are flexible and relatively strong, resisting buckling by multi-piconewton compressive forces and filament fracture by nanonewton tensile forces. In inducing cell motility, one end of the actin filament elongates while the other end contracts, presumably by myosin II molecular motors. Additionally, they function as part of actomyosin-driven contractile molecular motors, wherein the thin filaments serve as tensile platforms for myosin's ATP-dependent pulling action in muscle contraction and pseudopod advancement. Microfilaments have a tough, flexible framework which helps the cell in movement.
Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over 100 μM; its mass is roughly 42 kDa, with a diameter of 4 to 7 nm.
Listeria monocytogenes is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the host's cells and is one of the most virulent foodborne pathogens: 20 to 30% of foodborne listeriosis infections in high-risk individuals may be fatal. In the European Union, listeriosis follows an upward trend that began in 2008, causing 2,161 confirmed cases and 210 reported deaths in 2014, 16% more than in 2013. Listeriosis mortality rates are also higher in the EU than for other foodborne pathogens. Responsible for an estimated 1,600 illnesses and 260 deaths in the United States annually, listeriosis ranks third in total number of deaths among foodborne bacterial pathogens, with fatality rates exceeding even Salmonella spp. and Clostridium botulinum.
Listeria is a genus of bacteria that acts as an intracellular parasite in mammals. Until 1992, 10 species were known, each containing two subspecies. By 2020, 21 species had been identified. The genus is named in honour of the British pioneer of sterile surgery Joseph Lister. Listeria species are Gram-positive, rod-shaped, and facultatively anaerobic, and do not produce endospores. The major human pathogen in the genus Listeria is L. monocytogenes. It is usually the causative agent of the relatively rare bacterial disease listeriosis, an infection caused by eating food contaminated with the bacteria. Listeriosis can cause serious illness in pregnant women, newborns, adults with weakened immune systems and the elderly, and may cause gastroenteritis in others who have been severely infected.
Cell migration is a central process in the development and maintenance of multicellular organisms. Tissue formation during embryonic development, wound healing and immune responses all require the orchestrated movement of cells in particular directions to specific locations. Cells often migrate in response to specific external signals, including chemical signals and mechanical signals. Errors during this process have serious consequences, including intellectual disability, vascular disease, tumor formation and metastasis. An understanding of the mechanism by which cells migrate may lead to the development of novel therapeutic strategies for controlling, for example, invasive tumour cells.
Shigella flexneri is a species of Gram-negative bacteria in the genus Shigella that can cause diarrhea in humans. Several different serogroups of Shigella are described; S. flexneri belongs to group B. S. flexneri infections can usually be treated with antibiotics, although some strains have become resistant. Less severe cases are not usually treated because they become more resistant in the future. Shigella are closely related to Escherichia coli, but can be differentiated from E.coli based on pathogenicity, physiology and serology.
Pascale Cossart is a French bacteriologist who is affiliated with the Pasteur Institute of Paris. She is the foremost authority on Listeria monocytogenes, a deadly and common food-borne pathogen responsible for encephalitis, meningitis, bacteremia, gastroenteritis, and other diseases.
Actin-related protein 3 is a protein that in humans is encoded by the ACTR3 gene.
Actin-related protein 2 is a protein that in humans is encoded by the ACTR2 gene.
Protein enabled homolog is a protein that in humans is encoded by the ENAH gene.
Amoeboid movement is the most typical mode of locomotion in adherent eukaryotic cells. It is a crawling-like type of movement accomplished by protrusion of cytoplasm of the cell involving the formation of pseudopodia ("false-feet") and posterior uropods. One or more pseudopodia may be produced at a time depending on the organism, but all amoeboid movement is characterized by the movement of organisms with an amorphous form that possess no set motility structures.
The Actin assembly-inducing protein (ActA) is a protein encoded and used by Listeria monocytogenes to propel itself through a mammalian host cell. ActA is a bacterial surface protein comprising a membrane-spanning region. In a mammalian cell the bacterial ActA interacts with the Arp2/3 complex and actin monomers to induce actin polymerization on the bacterial surface generating an actin comet tail. The gene encoding ActA is named actA or prtB.
Arp2/3 complex is a seven-subunit protein complex that plays a major role in the regulation of the actin cytoskeleton. It is a major component of the actin cytoskeleton and is found in most actin cytoskeleton-containing eukaryotic cells. Two of its subunits, the Actin-Related Proteins ARP2 and ARP3, closely resemble the structure of monomeric actin and serve as nucleation sites for new actin filaments. The complex binds to the sides of existing ("mother") filaments and initiates growth of a new ("daughter") filament at a distinctive 70 degree angle from the mother. Branched actin networks are created as a result of this nucleation of new filaments. The regulation of rearrangements of the actin cytoskeleton is important for processes like cell locomotion, phagocytosis, and intracellular motility of lipid vesicles.
Paracytophagy is the cellular process whereby a cell engulfs a protrusion which extends from a neighboring cell. This protrusion may contain material which is actively transferred between the cells. The process of paracytophagy was first described as a crucial step during cell-to-cell spread of the intracellular bacterial pathogen Listeria monocytogenes, and is also commonly observed in Shigella flexneri. Paracytophagy allows these intracellular pathogens to spread directly from cell to cell, thus escaping immune detection and destruction. Studies of this process have contributed significantly to our understanding of the role of the actin cytoskeleton in eukaryotic cells.
Alex Mogilner is an American professor at the Courant Institute of Mathematical Sciences and the Department of Biology at New York University. His major contribution to science are in the areas of cell motility and division and innovations in cell imaging.
Rong Li is the Director of Mechanobiology Institute, a Singapore Research Center of Excellence, at the National University of Singapore. She is a Distinguished Professor at the National University of Singapore's Department of Biological Sciences and Bloomberg Distinguished Professor of Cell Biology and Chemical & Biomolecular Engineering at the Johns Hopkins School of Medicine and Whiting School of Engineering. She previously served as Director of Center for Cell Dynamics in the Johns Hopkins School of Medicine’s Institute for Basic Biomedical Sciences. She is a leader in understanding cellular asymmetry, division and evolution, and specifically, in how eukaryotic cells establish their distinct morphology and organization in order to carry out their specialized functions.
Daniel A. Portnoy is a microbiologist, the Edward E. Penhoet Distinguished Chair in Global Public Health and Infectious Diseases, and a Professor of Biochemistry, Biophysics and Structural Biology in the Department of Molecular and Cell Biology and in the Division of Microbiology in the Department of Plant and Microbial Biology at the University of California, Berkeley. He is one of the world's foremost experts on Listeria monocytogenes, the bacterium that causes the severe foodborne illness Listeriosis. He has made seminal contributions to multiple aspects of bacterial pathogenesis, cell biology, innate immunity, and cell mediated immunity using L. monocytogenes as a model system and has helped to push forward the use of attenuated L. monocytogenes as an immunotherapeutic tool in the treatment of cancer.
David G. Drubin is an American biologist, academic, and researcher. He is a Distinguished Professor of Cell and Developmental Biology at the University of California, Berkeley where he holds the Ernette Comby Chair in Microbiology.
Catherine G Galbraith is an American scientist and an Associate Professor of Biomedical Engineering at OHSU and Discovery Engine Investigator at Knight Cancer Institute, known for her work in cell mobility and cell migration as well as super-resolution microscopy. Together with James Galbraith, she heads the Galbraith Lab.
References
- ↑ Chytilova, Eva; Macas, Jiri; Sliwinska, Elwira; Rafelski, Susanne M.; Lambert, Georgina M.; Galbraith, David W. (2000). Lippincott-Schwartz, Jennifer (ed.). "Nuclear Dynamics in Arabidopsis thaliana". Molecular Biology of the Cell. 11 (8): 2733–2741. doi:10.1091/mbc.11.8.2733. ISSN 1059-1524. PMC 14952 . PMID 10930466.
- ↑ Rafelski, Susanne Marie (2005). Integrating bacterial polarity with host-cytoskeletal dynamics: initiation of listeria monocytogenes actin-based motility (Thesis).
- ↑ Rafelski, Susanne M.; Theriot, Julie A. (2006). "Mechanism of polarization of Listeria monocytogenes surface protein ActA". Molecular Microbiology. 59 (4): 1262–1279. doi:10.1111/j.1365-2958.2006.05025.x. ISSN 0950-382X. PMC 1413586 . PMID 16430699.
- ↑ Rafelski, Susanne M.; Alberts, Jonathan B.; Odell, Garrett M. (2009-07-10). Goodson, Holly (ed.). "An Experimental and Computational Study of the Effect of ActA Polarity on the Speed of Listeria monocytogenes Actin-based Motility". PLOS Computational Biology. 5 (7): e1000434. Bibcode:2009PLSCB...5E0434R. doi: 10.1371/journal.pcbi.1000434 . ISSN 1553-7358. PMC 2699634 . PMID 19593363.
- ↑ "Center for Cell Dynamics Friday Harbor Washington". celldynamics.org. Retrieved 2021-03-29.
- ↑ Rafelski, Susanne M.; Marshall, Wallace F. (2008). "Building the cell: design principles of cellular architecture". Nature Reviews Molecular Cell Biology. 9 (8): 593–602. doi:10.1038/nrm2460. ISSN 1471-0072. PMID 18648373. S2CID 211532.
- ↑ Rafelski, S. M.; Viana, M. P.; Zhang, Y.; Chan, Y.-H. M.; Thorn, K. S.; Yam, P.; Fung, J. C.; Li, H.; Costa, L. d. F.; Marshall, W. F. (2012). "Mitochondrial Network Size Scaling in Budding Yeast". Science. 338 (6108): 822–824. Bibcode:2012Sci...338..822R. doi:10.1126/science.1225720. ISSN 0036-8075. PMC 3602416 . PMID 23139336.
- ↑ "UC Irvine - Faculty Profile System". www.faculty.uci.edu. Retrieved 2021-03-29.
- ↑ "Prime suspect—Susanne Rafelski will explore latest evidence linking mitochondria and cancer biology at ASCB 2015". www.newswise.com. 16 November 2015. Retrieved 2021-03-29.
- ↑ "Allen Institute For Cell Science Announces Leadership Changes". markets.businessinsider.com. Retrieved 2021-03-29.
- ↑ "Susanne Rafelski". alleninstitute.org. Retrieved 2021-03-29.
- ↑ "Allen Institute for Cell Science announces leadership changes". Allen Institute. 2020-12-11. Retrieved 2021-03-29.
- ↑ Dance, Amber (2021). "AI spots cell structures that humans can't". Nature. 592 (7852): 154–155. Bibcode:2021Natur.592..154D. doi: 10.1038/d41586-021-00812-7 . ISSN 0028-0836. PMID 33782599.
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