High-resolution structures of the actomyosin-V complex in three nucleotide states provide insights into the force generation mechanism

Pospich, Sabrina; Sweeney, H. Lee; Houdusse, Anne; Raunser, Stefan

doi:10.7554/elife.73724

Cited by 36 publications

(88 citation statements)

References 126 publications

(360 reference statements)

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“…9 ). Interestingly, the position where TcART binds to F-actin partly overlaps with the position of other F-actin interacting proteins and peptides, such as myosin-V 41 , ExoY toxin from Pseudomonas aeruginosa 42 , and the Lifeact peptide 43 , 44 . In particular, all these proteins possess a hydrophobic residue that is homologous to Y183 of TcART (M515 in myosin-V, F374 in ExoY and F10 in Lifeact).…”

Section: Discussionmentioning

confidence: 99%

Mechanism of threonine ADP-ribosylation of F-actin by a Tc toxin

et al. 2022

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Tc toxins deliver toxic enzymes into host cells by a unique injection mechanism. One of these enzymes is the actin ADP-ribosyltransferase TccC3, whose activity leads to the clustering of the cellular cytoskeleton and ultimately cell death. Here, we show in atomic detail how TccC3 modifies actin. We find that the ADP-ribosyltransferase does not bind to G-actin but interacts with two consecutive actin subunits of F-actin. The binding of TccC3 to F-actin occurs via an induced-fit mechanism that facilitates access of NAD+ to the nucleotide binding pocket. The following nucleophilic substitution reaction results in the transfer of ADP-ribose to threonine-148 of F-actin. We demonstrate that this site-specific modification of F-actin prevents its interaction with depolymerization factors, such as cofilin, which impairs actin network turnover and leads to steady actin polymerization. Our findings reveal in atomic detail a mechanism of action of a bacterial toxin through specific targeting and modification of F-actin.

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Section: Discussionmentioning

confidence: 99%

Mechanism of threonine ADP-ribosylation of F-actin by a Tc toxin

et al. 2022

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“…An interaction between loop 4 and actin is supported by both cryo-EM and computational work, where evidence suggests that residue R369 is critical to this interface. Cryo-EM structures of skeletal muscle myosin II [ 24 ] and myosin V [ 27 ] bound to F-actin show direct electrostatic interactions between loop 4 and actin, though loop 4 of myosin V localizes closer towards the cardiomyopathy loop where it forms an intramolecular hydrogen bond. A molecular dynamics simulation [ 7 ] of a cryo-EM structure of actomyosin [ 21 ] incorporating the myosin II [ 28 ] and myosin V [ 29 ] crystal structures, revealed that the residue homologous to β-cardiac myosin R369 (R371) forms an electrostatic interaction with D311 of actin in the rigor conformation [ 7 ].…”

Section: Discussionmentioning

confidence: 99%

The R369 Myosin Residue within Loop 4 Is Critical for Actin Binding and Muscle Function in Drosophila

Trujillo

Hsu

Viswanathan

et al. 2022

IJMS

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The myosin molecular motor interacts with actin filaments in an ATP-dependent manner to yield muscle contraction. Myosin heavy chain residue R369 is located within loop 4 at the actin-tropomyosin interface of myosin’s upper 50 kDa subdomain. To probe the importance of R369, we introduced a histidine mutation of that residue into Drosophila myosin and implemented an integrative approach to determine effects at the biochemical, cellular, and whole organism levels. Substituting the similarly charged but bulkier histidine residue reduces maximal actin binding in vitro without affecting myosin ATPase activity. R369H mutants exhibit impaired flight ability that is dominant in heterozygotes and progressive with age in homozygotes. Indirect flight muscle ultrastructure is normal in mutant homozygotes, suggesting that assembly defects or structural deterioration of myofibrils are not causative of reduced flight. Jump ability is also reduced in homozygotes. In contrast to these skeletal muscle defects, R369H mutants show normal heart ultrastructure and function, suggesting that this residue is differentially sensitive to perturbation in different myosin isoforms or muscle types. Overall, our findings indicate that R369 is an actin binding residue that is critical for myosin function in skeletal muscles, and suggest that more severe perturbations at this residue may cause human myopathies through a similar mechanism.

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“…This additional interaction may reduce the sliding velocity of non-muscle myosins [47]. Interestingly, the binding of myosin alters the structure of F-actin primarily at the DNase-binding loop (39-55aa) (Figure 3h), although such changes are dependent on isoforms [48]. A high-resolution structure of native vertebrate skeletal sarcomeres at different bands revealed by electron cryo-tomography shows that the two heads of double-headed myosin can interact with either a single actin filament or two separate actin filaments [49].…”

Section: How Abps Interact With Actinmentioning

confidence: 99%

Actin-Associated Proteins and Small Molecules Targeting the Actin Cytoskeleton

Gao,

Nakamura

2022

IJMS

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Actin-associated proteins (AAPs) act on monomeric globular actin (G-actin) and polymerized filamentous actin (F-actin) to regulate their dynamics and architectures which ultimately control cell movement, shape change, division; organelle localization and trafficking. Actin-binding proteins (ABPs) are a subset of AAPs. Since actin was discovered as a myosin-activating protein (hence named actin) in 1942, the protein has also been found to be expressed in non-muscle cells, and numerous AAPs continue to be discovered. This review article lists all of the AAPs discovered so far while also allowing readers to sort the list based on the names, sizes, functions, related human diseases, and the dates of discovery. The list also contains links to the UniProt and Protein Atlas databases for accessing further, related details such as protein structures, associated proteins, subcellular localization, the expression levels in cells and tissues, mutations, and pathology. Because the actin cytoskeleton is involved in many pathological processes such as tumorigenesis, invasion, and developmental diseases, small molecules that target actin and AAPs which hold potential to treat these diseases are also listed.

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High-resolution structures of the actomyosin-V complex in three nucleotide states provide insights into the force generation mechanism

Cited by 36 publications

References 126 publications

Mechanism of threonine ADP-ribosylation of F-actin by a Tc toxin

Mechanism of threonine ADP-ribosylation of F-actin by a Tc toxin

The R369 Myosin Residue within Loop 4 Is Critical for Actin Binding and Muscle Function in Drosophila

Actin-Associated Proteins and Small Molecules Targeting the Actin Cytoskeleton

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