Journal Article

PUBDB-2025-05842

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Myosin inhibition partially rescues the myofiber proteome in X-linked myotubular myopathy

Gerlach Melhedegaard, E. ; Rostedt, F.Extern* ; Gineste, C. ; Seaborne, R. A. E. ; Dugdale, H. F. ; Belhac, V. ; Zanoteli, E. ; Lawlor, M. W. ; Mack, D. L. ; Wallgren-Pettersson, C. ; Hessel, A. L.Extern* ; Jungbluth, H. ; Laporte, J. ; Saito, Y. ; Nishino, I. ; Ochala, J.Extern* ; Laitila, J.

2025
JCI Insight Ann Arbor, Michigan

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Please use a persistent id in citations: doi:10.1172/jci.insight.194868  doi:10.3204/PUBDB-2025-05842

Abstract: X-linked myotubular myopathy (XLMTM) due to MTM1 mutations is a rare and often lethal congenital myopathy. Its downstream molecular and cellular mechanisms are currently incompletely understood. The most abundant protein in muscle, myosin, has been implicated in the pathophysiology of other congenital myopathies. Hence, in the present study, we aimed to define whether myosin is also dysfunctional in XLMTM and whether it, thus, may constitute a potential drug target. To this end, we used skeletal muscle tissue from patients and canine/mouse models; we performed Mant-ATP chase experiments coupled with x-ray diffraction analyses and LC/MS-based proteomics studies. In patients with XLMTM, we found that myosin molecules are structurally disordered and preferably adopt their ATP-consuming biochemical state. This phosphorylation-related (mal)adaptation was mirrored by a striking remodeling of the myofiber energetic proteome in XLMTM dogs. In line with these, we confirmed an accrued myosin ATP consumption in mice lacking MTM1. Hence, we treated these with a myosin ATPase inhibitor, mavacamten. After a 4-week treatment period, we observed a partial restoration of the myofiber proteome, especially proteins involved in cytoskeletal, sarcomeric, and energetic pathways. Altogether, our study highlights myosin inhibition as a potentially new drug mechanism for the complex XLMTM muscle phenotype.

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Contributing Institute(s):

1. FS DOOR-User (FS DOOR-User)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
2. FS-Proposal: II-20221421 (II-20221421) (II-20221421)

Experiment(s):

1. PETRA Beamline P03 (PETRA III)

Appears in the scientific report 2025

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Database coverage:
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