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: [Gardini, Lucia; Arbore, Claudia; Pavone, Francesco S.; Capitanio, Marco] Univ Florence, LENS European Lab Nonlinear Spect, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy.
[Gardini, Lucia; Pavone, Francesco S.] CNR, Natl Inst Opt, Largo Fermi 6, I-50125 Florence, Italy.
[Heissler, Sarah M.; Yang, Yi; Sellers, James R.] NHLBI, Lab Mol Physiol, NIH, Bldg 10, Bethesda, MD 20892 USA.
[Arbore, Claudia; Pavone, Francesco S.; Capitanio, Marco] Univ Florence, Dept Phys & Astron, Via Sansone 1, I-50019 Sesto Fiorentino, Italy.
[Yang, Yi] 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.


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

KeyWords: microvillus inclusion disease; load-dependent kinetics; hand-over-hand; optical tweezers; stepping kinetics
DOI: 10.1038/s41467-018-05251-z

Citations: 22
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