Dissecting myosin-5B mechanosensitivity and calcium regulation at the single molecule level

Year: 2018

Authors: Gardini L., Heissler S.M., Arbore C., Yang Y., Sellers J. R., Pavone FS., Capitanio M.

Autors Affiliation: Univ Florence, LENS European Lab Nonlinear Spect, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy; CNR, Natl Inst Opt, Largo Fermi 6, I-50125 Florence, Italy; NHLBI, Lab Mol Physiol, NIH, Bldg 10, Bethesda, MD 20892 USA; Univ Florence, Dept Phys & Astron, Via Sansone 1, I-50019 Sesto Fiorentino, Italy; Hunan Agr Univ, Hunan Prov Key Lab Prot Engn Anim Vaccines, Changsha 410128, Hunan, Peoples R China.

Abstract: Myosin-5B is one of three members of the myosin-5 family of actin-based molecular motors. Despite its fundamental role in recycling endosome trafficking and in collective actin network dynamics, the molecular mechanisms underlying its motility are inherently unknown. Here we combine single-molecule imaging and high-speed laser tweezers to dissect the mechanoenzymatic properties of myosin-5B. We show that a single myosin-5B moves processively in 36-nm steps, stalls at similar to 2 pN resistive forces, and reverses its directionality at forces >2 pN. Interestingly, myosin-5B mechanosensitivity differs from that of myosin-5A, while it is strikingly similar to kinesin-1. In particular, myosin-5B run length is markedly and asymmetrically sensitive to force, a property that might be central to motor ensemble coordination. Furthermore, we show that Ca2+ does not affect the enzymatic activity of the motor unit, but abolishes myosin-5B processivity through calmodulin dissociation, providing important insights into the regulation of postsynaptic cargoes trafficking in neuronal cells.

Journal/Review: NATURE COMMUNICATIONS

Volume: 9      Pages from: 2844-1  to: 2844-12

More Information: We thank Fang Zhang for the preparation of F-actin and Michael Greenberg, Yale Goldman, and Michael Ostap for the alpha-actinin expression plasmid. We thank Yasuharu Takagi for help and discussion. This work was supported by the European Union’s Horizon 2020 research and innova tion program under grant agreement no. 654148 Laserlab-Europe, by the Italian Ministry of University and Research (FIRB Futuro in Ricerca 2013 grant no. RBFR13V4M2 and Flagship Project NANOMAX), and by Ente Cassa di Risparmio di Firenze to M.C. and F.S.P. J.R.S. was supported by the Intramural Research Program of the National Heart, Lung, and Blood Institute of the National Institutes of Health.
KeyWords: Load-dependent Kinetics; Hand-over-hand; Stepping Kinetics; Optical Tweezers; Power-stroke; Motor; Va; Transport; Processivity; Range
DOI: 10.1038/s41467-018-05251-z

Citations: 23
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