Journal of Muscle Research and Cell Motility最新文献

{"title":"A new set of equations for the simplified calibration of fluorescence Ca²⁺ transients in skeletal muscle fibers.","authors":"D Mejía-Raigosa,&nbsp;A F Milán,&nbsp;M A Giraldo,&nbsp;J C Calderón","doi":"10.1007/s10974-021-09597-8","DOIUrl":"https://doi.org/10.1007/s10974-021-09597-8","url":null,"abstract":"<p><p>The classical approach for calibrating non-ratiometric fluorescent Ca²⁺ dyes entails the measurement of the fluorescence maximum (F_max) and minimum (F_min), as well as the dissociation constant (Kd) of the Ca²⁺-Dye reaction (model 1). An alternative equation does not need the F_min but requires the rate constants k_on and k_off (model 2). However, both approaches are experimentally time consuming and the rate constants for several dyes are unknown. Here, we propose a set of equations (model 3) that simplify the calibration of fluorescent Ca²⁺ transients obtained with non-ratiometric dyes. This equation allows the calibration of signals without using the F_min: [Ca²⁺] = Kd(F - F_rest/F_max - F) + [Ca²⁺]_IR(F_max - F_rest/F_max - F), where [Ca²⁺]_IR is the resting [Ca²⁺]. If the classical calibration approach is followed, the F_min can be estimated from: F_min = F_rest - ([Ca²⁺]_IR(F_max - F_rest)/Kd). We tested the models' performance using signals obtained from enzymatically dissociated flexor digitorum brevis fibers of C57BL/6 mice loaded with Fluo-4, AM. Model 3 performed the same as model 2, and both gave peak [Ca²⁺] values 15 ± 0.3% (n = 3) lower than model 1, when we used our experimental F_min (1.24 ± 0.11 A.U., n = 4). However, when we used the mathematically estimated F_min (6.78 ± 0.2 A.U) for model 1, the peak [Ca²⁺] were similar for all three models. This suggests that the dye leakage makes a correct determination of the F_min unlikely and induces errors in the estimation of [Ca²⁺]. In conclusion, we propose simpler and time-saving equations that help to reliably calibrate cytosolic Ca²⁺ transients obtained with non-ratiometric fluorescent dyes. The use of the estimated F_min avoids the uncertainties associated with its experimental measurement.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"161-168"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10974-021-09597-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25376274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanosignaling pathways alter muscle structure and function by post-translational modification of existing sarcomeric proteins to optimize energy usage.","authors":"Brenda Russell, Christopher Solís","doi":"10.1007/s10974-021-09596-9","DOIUrl":"10.1007/s10974-021-09596-9","url":null,"abstract":"<p><p>A transduced mechanical signal arriving at its destination in muscle alters sarcomeric structure and function. A major question addressed is how muscle mass and tension generation are optimized to match actual performance demands so that little energy is wasted. Three cases for improved energy efficiency are examined: the troponin complex for tuning force production, control of the myosin heads in a resting state, and the Z-disc proteins for sarcomere assembly. On arrival, the regulation of protein complexes is often controlled by post-translational modification (PTM), of which the most common are phosphorylation by kinases, deacetylation by histone deacetylases and ubiquitination by E3 ligases. Another branch of signals acts not through peptide covalent bonding but via ligand interactions (e.g. Ca²⁺ and phosphoinositide binding). The myosin head and the regulation of its binding to actin by the troponin complex is the best and earliest example of signal destinations that modify myofibrillar contractility. PTMs in the troponin complex regulate both the efficiency of the contractile function to match physiologic demand for work, and muscle mass via protein degradation. The regulation of sarcomere assembly by integration of incoming signaling pathways causing the same PTMs or ligand binding are discussed in response to mechanical loading and unloading by the Z-disc proteins CapZ, α-actinin, telethonin, titin N-termini, and others. Many human mutations that lead to cardiomyopathy and heart disease occur in the proteins discussed above, which often occur at their PTM or ligand binding sites.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"367-380"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8338793/pdf/nihms-1690087.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25376276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acidosis modifies effects of phosphorylated tropomyosin on the actin-myosin interaction in the myocardium.","authors":"Galina V Kopylova,&nbsp;Alexander M Matyushenko,&nbsp;Valentina Y Berg,&nbsp;Dmitrii I Levitsky,&nbsp;Sergey Y Bershitsky,&nbsp;Daniil V Shchepkin","doi":"10.1007/s10974-020-09593-4","DOIUrl":"https://doi.org/10.1007/s10974-020-09593-4","url":null,"abstract":"<p><p>Phosphorylation of α-tropomyosin (Tpm1.1), a predominant Tpm isoform in the myocardium, is one of the regulatory mechanisms of the heart contractility. The Tpm 1.1 molecule has one site of phosphorylation, Ser283. The degree of the Tpm phosphorylation decreases with age and also changes in heart pathologies. Myocardial pathologies, in particular ischemia, are usually accompanied by pH lowering in the cardiomyocyte cytosol. We studied the effects of acidosis on the structural and functional properties of the pseudo-phosphorylated form of Tpm1.1 with the S283D substitution. We found that in acidosis, the interaction of the N- and C-ends of the S283D Tpm molecules decreases, whereas that of WT Tpm does not change. The pH lowering increased thermostability of the complex of F-actin with S283D Tpm to a greater extent than with WT Tpm. Using an in vitro motility assay with NEM- modified myosin as a load, we assessed the effect of the Tpm pseudo-phosphorylation on the force of the actin-myosin interaction. In acidosis, the force generated by myosin in the interaction with thin filaments containing S283D Tpm was higher than with those containing WT Tpm. Also, the pseudo-phosphorylation increased the myosin ability to resist a load. We conclude that ischemia changes the effect of the phosphorylated Tpm on the contractile function of the myocardium.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"343-353"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10974-020-09593-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38774567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The RNA surveillance factor UPF1 regulates the migration and adhesion of porcine skeletal muscle satellite cells.","authors":"Yanjie Tan,&nbsp;Yi Jin,&nbsp;Sheng Wang,&nbsp;Jianhua Cao,&nbsp;Zhuqing Ren","doi":"10.1007/s10974-020-09585-4","DOIUrl":"https://doi.org/10.1007/s10974-020-09585-4","url":null,"abstract":"<p><p>Skeletal muscle satellite cells (SCs) play an important role in the repairment and regeneration of damaged muscle. The activation, proliferation, migration, and differentiation of SCs are essential to the response to muscle injury. Up-frameshift 1 (UPF1) is involved in the regulation of many developmental processes. However, the role of UPF1 and its associated regulatory mechanism in SCs are still unclear. Here, we analyzed changes in the transcriptome of porcine SCs with UPF1 knockdown. The results showed that focal adhesion and actin cytoskeleton processes were regulated by UPF1. We also confirmed experimentally that UPF1 promoted SC migration and adhesion by regulating the expression of F-Actin, Vinculin, and several adhesion-related genes. Furthermore, we found that phosphorylated focal adhesion kinase (p-FAK) was down-regulated by UPF1 knockdown. This study identifies the role of UPF1 in regulating SC migration and adhesion and therefore provides new insight into the regulatory mechanism of UPF1 in the process of repairing damaged muscle.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"203-217"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10974-020-09585-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38533212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive guide to genetic variants and post-translational modifications of cardiac troponin C.","authors":"Tyler R Reinoso,&nbsp;Maicon Landim-Vieira,&nbsp;Yun Shi,&nbsp;Jamie R Johnston,&nbsp;P Bryant Chase,&nbsp;Michelle S Parvatiyar,&nbsp;Andrew P Landstrom,&nbsp;Jose R Pinto,&nbsp;Hanna J Tadros","doi":"10.1007/s10974-020-09592-5","DOIUrl":"https://doi.org/10.1007/s10974-020-09592-5","url":null,"abstract":"<p><p>Familial cardiomyopathy is an inherited disease that affects the structure and function of heart muscle and has an extreme range of phenotypes. Among the millions of affected individuals, patients with hypertrophic (HCM), dilated (DCM), or left ventricular non-compaction (LVNC) cardiomyopathy can experience morphologic changes of the heart which lead to sudden death in the most detrimental cases. TNNC1, the gene that codes for cardiac troponin C (cTnC), is a sarcomere gene associated with cardiomyopathies in which probands exhibit young age of presentation and high death, transplant or ventricular fibrillation events relative to TNNT2 and TNNI3 probands. Using GnomAD, ClinVar, UniProt and PhosphoSitePlus databases and published literature, an extensive list to date of identified genetic variants in TNNC1 and post-translational modifications (PTMs) in cTnC was compiled. Additionally, a recent cryo-EM structure of the cardiac thin filament regulatory unit was used to localize each functionally studied amino acid variant and each PTM (acetylation, glycation, s-nitrosylation, phosphorylation) in the structure of cTnC. TNNC1 has a large number of variants (> 100) relative to other genes of the same transcript size. Surprisingly, the mapped variant amino acids and PTMs are distributed throughout the cTnC structure. While many cardiomyopathy-associated variants are localized in α-helical regions of cTnC, this was not statistically significant χ² (p = 0.72). Exploring the variants in TNNC1 and PTMs of cTnC in the contexts of cardiomyopathy association, physiological modulation and potential non-canonical roles provides insights into the normal function of cTnC along with the many facets of TNNC1 as a cardiomyopathic gene.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"323-342"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10974-020-09592-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38596003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulatory mechanisms of ryanodine receptor/Ca²⁺ release channel revealed by recent advancements in structural studies.","authors":"Haruo Ogawa,&nbsp;Nagomi Kurebayashi,&nbsp;Toshiko Yamazawa,&nbsp;Takashi Murayama","doi":"10.1007/s10974-020-09575-6","DOIUrl":"https://doi.org/10.1007/s10974-020-09575-6","url":null,"abstract":"<p><p>Ryanodine receptors (RyRs) are huge homotetrameric Ca²⁺ release channels localized to the sarcoplasmic reticulum. RyRs are responsible for the release of Ca²⁺ from the SR during excitation-contraction coupling in striated muscle cells. Recent revolutionary advancements in cryo-electron microscopy have provided a number of near-atomic structures of RyRs, which have enabled us to better understand the architecture of RyRs. Thus, we are now in a new era understanding the gating, regulatory and disease-causing mechanisms of RyRs. Here we review recent advances in the elucidation of the structures of RyRs, especially RyR1 in skeletal muscle, and their mechanisms of regulation by small molecules, associated proteins and disease-causing mutations.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"291-304"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10974-020-09575-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37628969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms of Frank-Starling law of the heart and stretch activation in striated muscles may have a common molecular origin.","authors":"Masataka Kawai, Jian-Ping Jin","doi":"10.1007/s10974-020-09595-2","DOIUrl":"10.1007/s10974-020-09595-2","url":null,"abstract":"<p><p>Vertebrate cardiac muscle generates progressively larger systolic force when the end diastolic chamber volume is increased, a property called the \"Frank-Starling Law\", or \"length dependent activation (LDA)\". In this mechanism a larger force develops when the sarcomere length (SL) increased, and the overlap between thick and thin filament decreases, indicating increased production of force per unit length of the overlap. To account for this phenomenon at the molecular level, we examined several hypotheses: as the muscle length is increased, (1) lattice spacing decreases, (2) Ca²⁺ sensitivity increases, (3) titin mediated rearrangement of myosin heads to facilitate actomyosin interaction, (4) increased SL activates cross-bridges (CBs) in the super relaxed state, (5) increased series stiffness at longer SL promotes larger elementary force/CB to account for LDA, and (6) stretch activation (SA) observed in insect muscles and LDA in vertebrate muscles may have similar mechanisms. SA is also known as delayed tension or oscillatory work, and universally observed among insect flight muscles, as well as in vertebrate skeletal and cardiac muscles. The sarcomere stiffness observed in relaxed muscles may significantly contributes to the mechanisms of LDA. In vertebrate striated muscles, the sarcomere stiffness is mainly caused by titin, a single filamentary protein spanning from Z-line to M-line and tightly associated with the myosin thick filament. In insect flight muscles, kettin connects Z-line and the thick filament to stabilize the sarcomere structure. In vertebrate cardiac muscles, titin plays a similar role, and may account for LDA and may constitute a molecular mechanism of Frank-Starling response.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"355-366"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10905364/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25360548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"2-D08 treatment regulates C2C12 myoblast proliferation and differentiation via the Erk1/2 and proteasome signaling pathways.","authors":"Hyunju Liu,&nbsp;Su-Mi Lee,&nbsp;Hosouk Joung","doi":"10.1007/s10974-021-09605-x","DOIUrl":"https://doi.org/10.1007/s10974-021-09605-x","url":null,"abstract":"<p><p>SUMOylation is one of the post-translational modifications that involves the covalent attachment of the small ubiquitin-like modifier (SUMO) to the substrate. SUMOylation regulates multiple biological processes, including myoblast proliferation, differentiation, and apoptosis. 2-D08 is a synthetically available flavone, which acts as a potent cell-permeable SUMOylation inhibitor. Its mechanism of action involves preventing the transfer of SUMO from the E2 thioester to the substrate without influencing SUMO-activating enzyme E1 (SAE-1/2) or E2 Ubc9-SUMO thioester formation. However, both the effects and mechanisms of 2-D08 on C2C12 myoblast cells remain unclear. In the present study, we found that treatment with 2-D08 inhibits C2C12 cell proliferation and differentiation. We confirmed that 2-D08 significantly hampers the viability of C2C12 cells. Additionally, it inhibited myogenic differentiation, decreasing myosin heavy chain (MHC), MyoD, and myogenin expression. Furthermore, we confirmed that 2-D08-mediated anti-myogenic effects impair myoblast differentiation and myotube formation, reducing the number of MHC-positive C2C12 cells. In addition, we found that 2-D08 induces the activation of ErK1/2 and the degradation of MyoD and myogenin in C2C12 cells. Taken together, these results indicated that 2-D08 treatment results in the deregulated proliferation and differentiation of myoblasts. However, further research is needed to investigate the long-term effects of 2-D08 on skeletal muscles.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"193-202"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10974-021-09605-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39243811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Septins, a cytoskeletal protein family, with emerging role in striated muscle.","authors":"Mónika Gönczi,&nbsp;Beatrix Dienes,&nbsp;Nóra Dobrosi,&nbsp;János Fodor,&nbsp;Norbert Balogh,&nbsp;Tamás Oláh,&nbsp;László Csernoch","doi":"10.1007/s10974-020-09573-8","DOIUrl":"https://doi.org/10.1007/s10974-020-09573-8","url":null,"abstract":"<p><p>Appropriate organization of cytoskeletal components are required for normal distribution and intracellular localization of different ion channels and proteins involved in calcium homeostasis, signal transduction, and contractile function of striated muscle. Proteins of the contractile system are in direct or indirect connection with the extrasarcomeric cytoskeleton. A number of other molecules which have essential role in regulating stretch-, voltage-, and chemical signal transduction from the surface into the cytoplasm or other intracellular compartments are already well characterized. Sarcomere, the basic contractile unit, is comprised of a precisely organized system of thin (actin), and thick (myosin) filaments. Intermediate filaments connect the sarcomeres and other organelles (mitochondria and nucleus), and are responsible for the cellular integrity. Interacting proteins have a very diverse function in coupling of the intracellular assembly components and regulating the normal physiological function. Despite the more and more intense investigations of a new cytoskeletal protein family, the septins, only limited information is available regarding their expression and role in striated, especially in skeletal muscles. In this review we collected basic and specified knowledge regarding this protein group and emphasize the importance of this emerging field in skeletal muscle biology.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"251-265"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10974-020-09573-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37558445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caffeine as a tool to investigate sarcoplasmic reticulum and intracellular calcium dynamics in human skeletal muscles.","authors":"Carlo Reggiani","doi":"10.1007/s10974-020-09574-7","DOIUrl":"https://doi.org/10.1007/s10974-020-09574-7","url":null,"abstract":"<p><p>Caffeine is worldwide used for its power to increase cognitive and physical performance. The ergogenic effects of caffeine, however, do not depend on a direct action on muscles. Actually, the actions of caffeine on skeletal muscles, take place at millimolar concentrations which are far above the micromolar level reached after a regular consumption of coffee or similar drinks, and close to a lethal concentration. At millimolar concentrations caffeine exerts a powerful effect on sarcoplasmic reticulum (SR) activating the release of calcium via ryanodine receptors and, possibly, inhibiting calcium reuptake. For this reason caffeine has become a valuable tool for studying SR function and for diagnostics of SR related muscle disorders. This review aims to briefly describe the effects and the mechanism of action of caffeine on sarcoplasmic reticulum and to focus on its use to study intracellular calcium dynamics in human muscle fibers in physiological and pathological conditions.</p>","PeriodicalId":16422,"journal":{"name":"Journal of Muscle Research and Cell Motility","volume":"42 2","pages":"281-289"},"PeriodicalIF":2.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10974-020-09574-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37624108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}