The M-band: The underestimated part of the sarcomere

Citation:

Lange S, Pinotsis N, Agarkova I, Ehler E. The M-band: The underestimated part of the sarcomere. Biochim Biophys Acta Mol Cell Res. 2020;1867:118440.

Abstract:

The sarcomere is the basic unit of the myofibrils, which mediate skeletal and cardiac Muscle contraction. Two transverse structures, the Z-disc and the M-band, anchor the thin (actin and associated proteins) and thick (myosin and associated proteins) filaments to the elastic filament system composed of titin. A plethora of proteins are known to be integral or associated proteins of the Z-disc and its structural and signalling role in muscle is better understood, while the molecular constituents of the M-band and its function are less well defined. Evidence discussed here suggests that the M-band is important for managing force imbalances during active muscle contraction. Its molecular composition is fine-tuned, especially as far as the structural linkers encoded by members of the myomesin family are concerned and depends on the specific mechanical characteristics of each particular muscle fibre type. Muscle activity signals from the M-band to the nucleus and affects transcription of sarcomeric genes, especially via serum response factor (SRF). Due to its important role as shock absorber in contracting muscle, the M-band is also more and more recognised as a contributor to muscle disease.

Notes:

Lange, StephanPinotsis, NikosAgarkova, IrinaEhler, ElisabethengRE/13/2/30182/BHF_/British Heart Foundation/United KingdomMR/R017050/1/MRC_/Medical Research Council/United KingdomP30 NS047101/NS/NINDS NIH HHS/S10 OD021724/OD/NIH HHS/R01 HL128457/HL/NHLBI NIH HHS/S10 OD016234/OD/NIH HHS/Research Support, Non-U.S. Gov'tReviewNetherlandsBiochim Biophys Acta Mol Cell Res. 2020 Mar;1867(3):118440. doi: 10.1016/j.bbamcr.2019.02.003. Epub 2019 Feb 7.

Contact Details

Biochemistry, Chemistry Department
National and Kapodistrian University of Athens
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Nikos Pinotsis

Associate Professor, Chemistry