7R8V

Cryo-EM structure of the ADP state actin filament

Summary for 7R8V

• Entry DOI: 10.2210/pdb7r8v/pdb
• EMDB information: 24321
• Descriptor: Actin, alpha skeletal muscle, intermediate form, ADENOSINE-5'-DIPHOSPHATE, MAGNESIUM ION (3 entities in total)
• Functional Keywords: filamentous actin, cytoskeleton, adhesion, contractility, cell adhesion
• Biological source: Gallus gallus (Chicken)
• Total number of polymer chains: 5
• Total formula weight: 209193.67

Authors

Gong, R.,Espinosa de los Reyes, S.,Reynolds, M.J.,Gurel, P.,Alushin, G.M. (deposition date: 2021-06-27, release date: 2021-07-28, Last modification date: 2022-08-03)

Primary citation

Gong, R.,Jiang, F.,Moreland, Z.G.,Reynolds, M.J.,de Los Reyes, S.E.,Gurel, P.,Shams, A.,Heidings, J.B.,Bowl, M.R.,Bird, J.E.,Alushin, G.M.
Structural basis for tunable control of actin dynamics by myosin-15 in mechanosensory stereocilia.
Sci Adv, 8:eabl4733-eabl4733, 2022

PubMed Abstract: The motor protein myosin-15 is necessary for the development and maintenance of mechanosensory stereocilia, and mutations in myosin-15 cause hereditary deafness. In addition to transporting actin regulatory machinery to stereocilia tips, myosin-15 directly nucleates actin filament ("F-actin") assembly, which is disrupted by a progressive hearing loss mutation (p.D1647G, ""). Here, we present cryo-electron microscopy structures of myosin-15 bound to F-actin, providing a framework for interpreting the impacts of deafness mutations on motor activity and actin nucleation. Rigor myosin-15 evokes conformational changes in F-actin yet maintains flexibility in actin's D-loop, which mediates inter-subunit contacts, while the mutant locks the D-loop in a single conformation. Adenosine diphosphate-bound myosin-15 also locks the D-loop, which correspondingly blunts actin-polymerization stimulation. We propose myosin-15 enhances polymerization by bridging actin protomers, regulating nucleation efficiency by modulating actin's structural plasticity in a myosin nucleotide state-dependent manner. This tunable regulation of actin polymerization could be harnessed to precisely control stereocilium height.

PubMed: 35857845
DOI: 10.1126/sciadv.abl4733

Experimental method

ELECTRON MICROSCOPY (2.82 Å)