Titin-dependent biomechanical feedback tailors sarcomeres to specialised muscle functions in insects

Loreau, V.; Koolhaas, W.; Chan, E. H.; De Bossier, P.; Brouilly, N.; Avosani, S.; Sane, A.; Pitaval, C.; Reiter, S.; Luis, N. M.; Mangeol, P.; von Philipsborn, A. C.; Rupprecht, J.-F.; Goerlich, D.; Habermann, B. H.; Schnorrer, F.

doi:10.1101/2024.09.30.615857

bioRxiv · 10.1101/2024.09.30.615857

Titin-dependent biomechanical feedback tailors sarcomeres to specialised muscle functions in insects

Loreau, V.·Koolhaas, W.·Chan, E. H.·De Bossier, P.·Brouilly, N.·Avosani, S.·Sane, A.·Pitaval, C.·Reiter, S.·Luis, N. M.·Mangeol, P.·von Philipsborn, A. C.·Rupprecht, J.-F.·Goerlich, D.·Habermann, B. H.·Schnorrer, F.

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Abstract

Sarcomeres are the contractile units of muscles that enable animals to move. Insect muscles are remarkable examples because they use extremely different contraction frequencies (ranging from [~]1 to 1000 Hz) and amplitudes for flying, walking and crawling. This is puzzling because sarcomeres are built from essentially the same actin-myosin components. We show here that the giant protein titin is the key to this functional specialisation. I-band titin spans and determines the length of the sarcomeric I-band, and occurs in muscle-type-specific isoforms. Surprisingly, it also rules the length of the force-generating myosin filament in a force feedback mechanism, even though it is not present there. We provide evidence for this model and its validity beyond insects. SummaryHere we identified a mechanical mechanism that instructs sarcomeres to fulfill the specific needs of different muscle types.

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Loreau, V., Koolhaas, W., Chan, E. H., De Bossier, P., Brouilly, N., Avosani, S., Sane, A., Pitaval, C., Reiter, S., Luis, N. M., Mangeol, P., von Philipsborn, A. C., Rupprecht, J.-F., Goerlich, D., Habermann, B. H., Schnorrer, F.. 2024-10-01. Titin-dependent biomechanical feedback tailors sarcomeres to specialised muscle functions in insects. https://doi.org/10.1101/2024.09.30.615857

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