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Neuromuscular Physiology
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
Several proteins make up the Z-disc including spectrin, vimentin, synemin, desmin, and α-actinin. Actin myofilaments are attached to both sides of the Z-discs by α-actinin (127). Desmin, vimentin, and synemin form a structural scaffolding that wraps around the actin myofibrils and the Z-disc. The central part of α-actinin consists of four tandem spectrin-like repeats each of which comprises a triple α-helix anti-parallel bundle. The specialized ends of the dimer allow α-actinin to crosslink with actin myofilaments. Together these proteins serve to hold the actin myofibrils in position at rest and during stretch or contraction. Additionally, Z-disc proteins are connected to the cytoskeletal proteins in the sarcolemma and basement membrane and ultimately to the endomysium connective tissue surrounding the muscle fiber (see Table 1.2).
Integrins, Integrin Regulators, and the Extracellular Matrix
Published in Bruce S. Bochner, Adhesion Molecules in Allergic Disease, 2020
Stephen W. Hunt, Sirid-Aimée Kellermann, Yoji Shimizu
Recently, Lewis and Schwartz (121) mapped association of cytoskeletal elements with β1 in vivo. Colocalization of FAK, talin, and actin with a transfected chicken β1 protein expressed in mouse NIH 3T3 cells was dependent on a common region of the carboxy-terminus of β1, while α-actinin colocalization appeared to require a more membrane-proximal sequence (Fig. 2). These results, in combination with earlier work, led the authors to propose that the carboxy-terminal region, containing two NPXY motifs, is necessary for talin association. Filardo and coworkers (124) showed that similar motifs in the β3 cytoplasmic tail were important for adhesion, spreading, and migration of melanoma cells (Fig. 2). Similarly, several mutations in the NXXY motif of the β3 cytoplasmic tail abolished cell spreading and FAC formation in COS cell transfectants (125). These data assign cytoskeletal interaction roles to these two motifs in the β3 cytoplasmic tail. In addition, mutations in two other regions of β3 (727–733, 752) inhibited β3 integrin recruitment to preformed FACs. This region is homologous to that found in β1 to be important in interactions with α-actinin (119) (Fig. 2).
Hereditary Multiple Osteochondromas
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Germline loss-of-function mutations (e.g., nonsense, frameshift, splice site, missense variants) in the EXT1 and EXT2 genes leading to premature terminations of the EXT proteins cause HS deficiency and subsequent cytoskeletal abnormalities (e.g., actin accumulation, excessive bundling by alpha-actinin, and abnormal presence of muscle-specific alpha-actin) [1].
ACTN3 R577X polymorphism related to sarcopenia and physical fitness in active older women
Published in Climacteric, 2021
C. Romero-Blanco, M. J. Artiga González, A. Gómez-Cabello, S. Vila-Maldonado, J. A. Casajús, I. Ara, S. Aznar
As well as the health benefits of physical activity in the elderly, investigating whether genetics determine better physical fitness or muscle mass8,9 is also of great interest. One of the most studied genetic polymorphisms has been ACTN3 R577X at position 1747 in exon 16, where an arginine turns into a codon stop due to the replacement of a cytosine by a thymine10. Homozygous XX people cannot produce the ACTN3 protein in the muscle, something estimated to take place in approximately 18% of the population11. ACTN3 is a structural protein and the predominant component of the Z areas of the sarcomere; α-actinin-3 deficiency in the general population seems to be connected to an age-related decrease of muscle mass and physical strength12.
Differential gene expression and gene-set enrichment analysis in Caco-2 monolayers during a 30-day timeline with Dexamethasone exposure
Published in Tissue Barriers, 2019
J.M. Robinson, S. Turkington, S.A. Abey, N. Kenea, W.A. Henderson
Gene set enrichment analysis indicates putative altered cellular functions; these are representative gene expression associated with biological processes of polarization and senescence (Fig. 2c, 3b, Supplementary Results). Increased expression of Claudins 3, 4, 7, and 15 (CLDN3, 4, 7, 15) are observed from the ‘Tight junction interactions’ pathway. Decreased expression is seen in Beta-Catenin 1 (CTNNB1) and ZO-1 (TJP), Rho GTPase ROCK1, and others from the ‘Apoptotic cleavage of cellular proteins’ pathway. Decreased expression is also seen in ‘Cyclin-D associated events in G1ʹ pathway including Cyclin D1 and D2 (CCND1, 2) and Cyclin-dependent kinase 4 (CDK4). Actin cytoskeleton genes Actin B (ACTB) and Actinin (ACTN1) have lowered expression, with actomyosin assembly showing variable expression, putatively associated with reorganization of the apical band cytoskeletal structure in epithelia. Also seen is decreased expression in the miRNA biogenesis components Drosha and Exportin 5 (XPO5).
Se@SiO2 nanocomposites attenuate doxorubicin-induced cardiotoxicity through combatting oxidative damage
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Guoying Deng, Changzhe Chen, Junjie Zhang, Yue Zhai, Jingpeng Zhao, Anqi Ji, Yingjie Kang, Xijian Liu, Kefei Dou, Qiugen Wang
Primary myocardial cells were acquired from mice. Myocardial cells in the blank group and H2O2 group received no treatments in the first 12 h, while cells from Se@SiO2 group and H2O2 + Se@SiO2 group were treated with 40 μg/ml Se@SiO2 for 12 h. In the subsequent 12 h, the H2O2 and H2O2 + Se@SiO2 group received 50 mM H2O2 for 12 h. After that, the cells were stained and examined according to the manufacturer’s protocol (Abcam, ab66110). Blue fluorescence shows DAPI and red the expression of a-actinin. In each group, several visual fields were selected randomly and images were acquired randomly by a Zeiss LSM710 laser confocal microscope (Carl Zeiss, Germany). Apoptosis rates were determined by the percentages of dead cells from three independent visual fields in each group.