Dynamic changes in the arrangement of myonuclei and the organization of the sarcoplasmic reticulum are important determinants of myofiber formation and muscle function. To find factors associated with muscle integrity, we perform an siRNA screen and identify SH3KBP1 as a new factor controlling myoblast fusion, myonuclear positioning, and myotube elongation. We find that the N-terminus of SH3KBP1 binds to dynamin-2 while the C-terminus associates with the endoplasmic reticulum through calnexin, which in turn control myonuclei dynamics and ER integrity, respectively. Additionally, in mature muscle fibers, SH3KBP1 contributes to the formation of triads and modulates the Excitation-Contraction Coupling process efficiency. In Dnm2 mice, a model for centronuclear myopathy (CNM), depletion of Sh3kbp1 expression aggravates CNM-related atrophic phenotypes and impaired autophagic flux in mutant skeletal muscle fiber. Altogether, our results identify SH3KBP1 as a new regulator of myofiber integrity and function.
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http://dx.doi.org/10.1038/s44319-025-00413-9 | DOI Listing |
EMBO Rep
March 2025
CNRS/UCBL1 UMR 5261 - INSERM U1315, U1217, INMG-PGNM, INSERM, CNRS, Claude Bernard University Lyon 1, Lyon, France.
Dynamic changes in the arrangement of myonuclei and the organization of the sarcoplasmic reticulum are important determinants of myofiber formation and muscle function. To find factors associated with muscle integrity, we perform an siRNA screen and identify SH3KBP1 as a new factor controlling myoblast fusion, myonuclear positioning, and myotube elongation. We find that the N-terminus of SH3KBP1 binds to dynamin-2 while the C-terminus associates with the endoplasmic reticulum through calnexin, which in turn control myonuclei dynamics and ER integrity, respectively.
View Article and Find Full Text PDFDev Biol
March 2025
Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. Electronic address:
During skeletal muscle development catabolic and anabolic events are finely orchestrated by several heat shock proteins (HSP). HSP90 are molecular chaperones which play an essential role in maintaining cellular homeostasis. Although HSP90 proteins have been widely studied in cancer cells, their role during skeletal myogenesis has not been completely explored.
View Article and Find Full Text PDFElife
March 2025
College of Animal Sciences, Zhejiang University, Hangzhou, China.
Conjugated linoleic acids (CLAs) can serve as a nutritional intervention to regulate quality, function, and fat infiltration in skeletal muscles, but the specific cytological mechanisms remain unknown. Here, we applied single-nucleus RNA-sequencing (snRNA-seq) to characterize the cytological mechanism of CLAs regulates fat infiltration in skeletal muscles based on pig models. We investigated the regulatory effects of CLAs on cell populations and molecular characteristics in pig muscles and found CLAs could promote the transformation of fast glycolytic myofibers into slow oxidative myofibers.
View Article and Find Full Text PDFPoult Sci
March 2025
Department of Food Science, Ontario Agricultural College, University of Guelph, Guelph, Ontario, Canada.
Gaping is a recently described condition that affects the Pectoralis minor (tender) muscle of broiler chickens, characterized by post-mortem separation of myofiber that leads to meat depreciation and economic losses. In this study, we aimed at understanding prevalence, morphological features, and transcriptomics signatures of this poorly understood myopathy. Between July 2022 and January 2023, a total of 5,180 chicken tenders were collected from 32 flocks across two plants in the USA, handling light (2.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
March 2025
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China.
Purpose: To explore whether there is a difference in postoperative extraocular muscle (EOM) remodeling between 1-month-old and 3-month-old rabbits.
Methods: Recession (n = 16) and resection (n = 16) were performed on the right superior rectus (SR) muscles of 1-month-old and 3-month-old rabbits. SR tissues were harvested 1 and 4 weeks post-surgery (n = 4 for each group), and mid-belly sections were used to assess myosin heavy chain (MyHC) isoform expression (fast 2X, embryonic, and neonatal MyHCs), activated satellite cells (SCs), and centrally nucleated myofibers.
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