China
Africa
Explore chapters and articles related to this topic
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
Globular actin (G-actin) is polymerized and forms F-actin. Two F-actins wrap around each other in an alpha-helix to form an actin myofilament. The regulatory proteins troponin and tropomyosin (forming regulatory units) are embedded in regular intervals in the actin myofilament.
Functional Anatomy
Published in James Crossley, Functional Exercise and Rehabilitation, 2021
The myofibril structure of myosin and actin allows contraction of muscle. Actin and myosin run parallel with each other. The thick myosin filaments have small heads called cross bridges. Folllowing electrical stimulus from a motor neuron, cross bridges interact with, bind to and pull against the thin actin filaments. This pulls the actin and myosin filaments together to produce movement, a process referred to as the sliding filament theory.
Food allergens
Published in Richard F. Lockey, Dennis K. Ledford, Allergens and Allergen Immunotherapy, 2020
Shrimp is the most studied of the Crustacea allergens, and tropomyosins are the major allergens. Tropomyosin is an actin-binding protein important in regulating muscle contractions. The IgE-binding epitopes of the shrimp allergen Pen a 1, a 36 kDa tropomyosin, are known [54,55]. The deduced amino-acid sequence of 284 amino acids from recombinant allergens and amino acid sequences from allergenic and nonallergenic vertebrate tropomyosins reveal 80%–99% and 51%–58% amino acid sequence homology, respectively. Analysis of the secondary structure of Pen a 1 shows an α-helical conformation that is typical for tropomyosins [56]. Tropomyosin allergens in lobster (Hom a 1) and crab (Cha f 1) have also been identified. Tropomyosin is also a pan-allergen for fish (tilapia, cod, albacore, and swordfish) [57,58] and mollusks (squid [59], oyster [60], and snail [61]). Several other allergens in shrimp and lobster are arginine kinase, myosin light chain 1 and 2, troponin C, and sarcoplasmic calcium-binding protein [14]. Arginine kinase, a major allergen in insect [62] and house dust mite [63] allergy is also a mollusk allergen found in octopus [64], thus causing cross-reactivity [65].
The roles of epidermal growth factor receptor in viral infections
Published in Growth Factors, 2022
Herpes simplex virus 1 (HSV-1) is another member of family Herpesviridae which is composed of a double-stranded linear DNA genome, an icosahedral nucleocapsid and an outer envelope with glycoprotein spikes. The infectious cycle of HSV-1 begins with a primary orolabial infection, establishment of latency in neurons and reactivation under specific conditions. Reactivation of HSV-1 causes cutaneous herpes, conjunctivitis, keratitis, encephalitis, or eczema herpeticum (Kukhanova, Korovina, and Kochetkov 2014; Kumar et al. 2016). Zheng et al. (2014) have reported that entry of HSV-1 into neuroblastoma (SK-N-SH) cell requires a cofilin-mediated biphasic remodelling of actin cytoskeleton. Similar to TGEV, EGFR signalling pathway is essential for the cofilin activity. In the early entry stage, HSV-1 induces phosphorylation of cofilin and F-actin polymerisation which facilitates virus entry via EGFR and its downstream PI3K/ERK1/2/ROCK/LIMK signalling pathways. Subsequently, cofilin is activated and promotes F-actin depolymerisation which allows viral penetration and intracellular trafficking. Treatments of EGFR inhibitor, AG1478 and siRNA inhibit phosphorylation of cofilin and disrupt HSV-1 entry (Figure 3(b)) (Zheng et al. 2014).
Development of a novel anti-biofilm peptide derived from profilin of Spodoptera frugiperda
Published in Biofouling, 2020
Amanda Carolina Borges da Silva, Janaina de Cassia Orlandi Sardi, Daniella Gorete Lourenço de Oliveira, Caio Fernando Ramalho de Oliveira, Helder Freitas dos Santos, Edson Lucas dos Santos, Edson Crusca, Marlon Henrique Cardoso, Octávio Luiz Franco, Maria Lígia Rodrigues Macedo
In this study, the profilin protein sequence from Spodoptera frugiperda was selected as a template to design a new synthetic AMP, named PEP-IA18. Profilin is a protein involved in the dynamics and restructuring of the actin cytoskeleton, which is essential for tissue regeneration and pathogen capture by immune cells (Mahoney et al. 1997; Krishnan and Moens 2009). To reduce the molecular size, to improve the selectivity for microorganism cells and to reduce the cytotoxicity of PEP-IA18 for human cells, modifications in the original profilin sequence were carried out with the aid of the Antimicrobial Peptide Database (APD3) and Collection of Anti-Microbial Peptides (CAMPr3) algorithms. As a result, PEP-IA18 showed antifungal activity against Candida spp., demonstrating potential as an alternative in the treatment of yeast infections.
Epithelial barrier dysfunction and cell migration induction via JNK/cofilin/actin by angubindin-1
Published in Tissue Barriers, 2020
Takumi Konno, Takayuki Kohno, Shin Kikuchi, Hiroshi Shimada, Seiro Satohisa, Tsuyoshi Saito, Masuo Kondoh, Takashi Kojima
To maintain the epithelial barrier, the presence of actin, which is one component of the cytoskeleton, is also important, and tricellular contacts are thought to have a specific mechanism in the regulation of the actin skeleton.9,10 Regulation of the epithelial barrier is one of the important functions of the actin cytoskeleton.11,12 Actin filaments are associated with the regulation of assembly and function of AJs and TJs.13–15 Cofilin is a member of the actin-depolymerizing factor (ADF)/cofilin family, which is a group of proteins that directly regulate actin dynamics.16 Dephosphorylation of phosphorylated cofilin activates its direct regulation of actin dynamics.16 It is reported that cofilin mediates tight junction opening by redistributing actin and tight junction proteins.17 It is also reported that the reversible increase in tight junction permeability induced by capsaicin, which is a pungent ingredient found in chili peppers, is mediated via cofilin-actin cytoskeletal dynamics.18