TY - JOUR
T1 - Ablation of Sam50 is associated with fragmentation and alterations in metabolism in murine and human myotubes
AU - Shao, Bryanna
AU - Killion, Mason
AU - Oliver, Ashton
AU - Vang, Chia
AU - Zeleke, Faben
AU - Neikirk, Kit
AU - Vue, Zer
AU - Garza-Lopez, Edgar
AU - Shao, Jian qiang
AU - Mungai, Margaret
AU - Lam, Jacob
AU - Williams, Qiana
AU - Altamura, Christopher T.
AU - Whiteside, Aaron
AU - Kabugi, Kinuthia
AU - McKenzie, Jessica
AU - Ezedimma, Maria
AU - Le, Han
AU - Koh, Alice
AU - Scudese, Estevão
AU - Vang, Larry
AU - Marshall, Andrea G.
AU - Crabtree, Amber
AU - Tanghal, Janelle I.
AU - Stephens, Dominique
AU - Koh, Ho Jin
AU - Jenkins, Brenita C.
AU - Murray, Sandra A.
AU - Cooper, Anthonya T.
AU - Williams, Clintoria
AU - Damo, Steven M.
AU - McReynolds, Melanie R.
AU - Gaddy, Jennifer A.
AU - Wanjalla, Celestine N.
AU - Beasley, Heather K.
AU - Hinton, Antentor
N1 - Publisher Copyright:
© 2024 The Author(s). Journal of Cellular Physiology published by Wiley Periodicals LLC.
PY - 2024/8
Y1 - 2024/8
N2 - The sorting and assembly machinery (SAM) Complex is responsible for assembling β-barrel proteins in the mitochondrial membrane. Comprising three subunits, Sam35, Sam37, and Sam50, the SAM complex connects the inner and outer mitochondrial membranes by interacting with the mitochondrial contact site and cristae organizing system complex. Sam50, in particular, stabilizes the mitochondrial intermembrane space bridging (MIB) complex, which is crucial for protein transport, respiratory chain complex assembly, and regulation of cristae integrity. While the role of Sam50 in mitochondrial structure and metabolism in skeletal muscle remains unclear, this study aims to investigate its impact. Serial block-face-scanning electron microscopy and computer-assisted 3D renderings were employed to compare mitochondrial structure and networking in Sam50-deficient myotubes from mice and humans with wild-type (WT) myotubes. Furthermore, autophagosome 3D structure was assessed in human myotubes. Mitochondrial metabolic phenotypes were assessed using Gas Chromatography-Mass Spectrometry-based metabolomics to explore differential changes in WT and Sam50-deficient myotubes. The results revealed increased mitochondrial fragmentation and autophagosome formation in Sam50-deficient myotubes compared to controls. Metabolomic analysis indicated elevated metabolism of propanoate and several amino acids, including ß-Alanine, phenylalanine, and tyrosine, along with increased amino acid and fatty acid metabolism in Sam50-deficient myotubes. Furthermore, impairment of oxidative capacity was observed upon Sam50 ablation in both murine and human myotubes, as measured with the XF24 Seahorse Analyzer. Collectively, these findings support the critical role of Sam50 in establishing and maintaining mitochondrial integrity, cristae structure, and mitochondrial metabolism. By elucidating the impact of Sam50-deficiency, this study enhances our understanding of mitochondrial function in skeletal muscle.
AB - The sorting and assembly machinery (SAM) Complex is responsible for assembling β-barrel proteins in the mitochondrial membrane. Comprising three subunits, Sam35, Sam37, and Sam50, the SAM complex connects the inner and outer mitochondrial membranes by interacting with the mitochondrial contact site and cristae organizing system complex. Sam50, in particular, stabilizes the mitochondrial intermembrane space bridging (MIB) complex, which is crucial for protein transport, respiratory chain complex assembly, and regulation of cristae integrity. While the role of Sam50 in mitochondrial structure and metabolism in skeletal muscle remains unclear, this study aims to investigate its impact. Serial block-face-scanning electron microscopy and computer-assisted 3D renderings were employed to compare mitochondrial structure and networking in Sam50-deficient myotubes from mice and humans with wild-type (WT) myotubes. Furthermore, autophagosome 3D structure was assessed in human myotubes. Mitochondrial metabolic phenotypes were assessed using Gas Chromatography-Mass Spectrometry-based metabolomics to explore differential changes in WT and Sam50-deficient myotubes. The results revealed increased mitochondrial fragmentation and autophagosome formation in Sam50-deficient myotubes compared to controls. Metabolomic analysis indicated elevated metabolism of propanoate and several amino acids, including ß-Alanine, phenylalanine, and tyrosine, along with increased amino acid and fatty acid metabolism in Sam50-deficient myotubes. Furthermore, impairment of oxidative capacity was observed upon Sam50 ablation in both murine and human myotubes, as measured with the XF24 Seahorse Analyzer. Collectively, these findings support the critical role of Sam50 in establishing and maintaining mitochondrial integrity, cristae structure, and mitochondrial metabolism. By elucidating the impact of Sam50-deficiency, this study enhances our understanding of mitochondrial function in skeletal muscle.
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U2 - 10.1002/jcp.31293
DO - 10.1002/jcp.31293
M3 - Article
C2 - 38770789
AN - SCOPUS:85193705655
SN - 0021-9541
VL - 239
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
IS - 8
M1 - e31293
ER -