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General Introductory Topics
Published in Vadim Backman, Adam Wax, Hao F. Zhang, A Laboratory Manual in Biophotonics, 2018
Vadim Backman, Adam Wax, Hao F. Zhang
Microfilaments are made of actin (Figure 1.14). Most actin fibers are found in the cell periphery or cortex near the plasma membrane. They control cell shape, are used in muscle contraction (in association with myosin–actin–myosin movement is the central mechanism behind muscle contraction), and are present in microvilli. Although the cytoskeleton is frequently thought of as a purely cytoplasmic structure, actin is present in the nucleus. This nuclear actin is critical in gene transcription. Depending on the type of RNA polymerase involved, actin may act as a molecular motor (in association with myosin) or help formation of the pre-initiation complex (β-actin). Nuclear actin also serves as a component of chromatin-remodeling complexes, which we discussed above. In the posttranscription phase, actin plays a role in the nuclear export of mRNAs.
The Cell as an Inspiration in Biomaterial Design
Published in Heather N. Hayenga, Helim Aranda-Espinoza, Biomaterial Mechanics, 2017
Helim Aranda-Espinoza, Katrina Adlerz
Microfilaments, also called actin filaments, are one of the three main components of the cytoskeleton and are made up of the protein actin. Actin is found in the cell in its monomer form globular actin (G-actin) or organized into linear filaments (F-actin). F-actin is a flexible polymer found at the cell cortex under the plasma membrane to provide mechanical support to the cell as well as throughout the cell where it is involved in cell migration, cell contractility, and cytokinesis [2].
Science in Textile Design
Published in Tarun Grover, Mugdha Thareja, Science in Design, 2020
Microfilaments are assembled from actin monomers that attach to the filament at one end (the “plus end”) and detach at the other (the “minus end”). In an intact filament, assembly and detachment are in equilibrium. But sometimes the filaments can shorten (more detachment) or lengthen (more assembly):Actin polymer (filament) ⇌ Actin monomers
Involvement of MAPK/ERK1/2 pathway in microcystin-induced microfilament reorganization in HL7702 hepatocytes
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Fei Yang, Cong Wen, Shuilin Zheng, Shu Yang, Jihua Chen, Xiangling Feng
Previously investigators demonstrated that MC produce their effects by inhibition of serine/threonine protein phosphatases1 (PP1) and 2A (PP2A) resulting in disruption of the dynamic equilibrium of protein phosphorylation as well as expression and activation of their downstream proteins, which leads to cytoskeletal reorganization (Ding, Shen, and Ong 2001; MacKintosh et al. 1990; Sun et al. 2001; Zeng et al. 2015). The cytoskeleton is a cellular network system containing different protein fibers intertwined with various regulatory proteins which play an important role in maintaining the morphology, intracellular transport, resist deformation, and change shape during movement of eukaryotic cells (Fletcher and Mullins 2010; Wickstead and Gull 2011). The cytoskeleton is predominantly composed of microfilaments (MF), microtubules (MT) and intermediate fibers (IF) (Sun et al. 2001; Zeng et al. 2015). Microfilaments, polymerized from actin molecules, exhibit various key functions involved in migration, secretion, and apoptosis (Papakonstanti and Stournaras 2008). Zeng et al. (2015) found that F-actin was depolymerized and that actin fibers aggregated around the cell periphery in the human liver HL7702 cells following exposure to 10 µM MC-LR. Further, Wang et al. (2014) reported that in the SMMC-7721 human liver cancer cell line, 10 µM MC-LR treatment induced actin to become concentrated and form bundles. Data thus suggest that MC-LR affects the cytoskeleton via interaction with actin fibers.
GFP fusion promotes the soluble and active expression of a pea actin isoform (PEAc1) in Escherichia coli
Published in Preparative Biochemistry & Biotechnology, 2023
Shaobin Zhang, Yiqing Wang, Xin Jiang, Zhanyong Wang
After negative staining, purified His-PEAc1-GFP exhibited a filamentous structure under TEM (Figure 9A). The diameter of the microfilament was about 9 nm, which is similar to the diameter of chicken muscle actins (Figure 9B) and other regular F-actins.[12,42]