Cryo‐EM reveals the complex architecture of dynactin's shoulder region and pointed end

Dynactin is a 1.1 MDa complex that activates the molecular motor dynein for ultra‐processive transport along microtubules. In order to do this, it forms a tripartite complex with dynein and a coiled‐coil adaptor. Dynactin consists of an actin‐related filament whose length is defined by its flexible...

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Veröffentlicht in:The EMBO journal Jg. 40; H. 8; S. e106164 - n/a
Hauptverfasser: Lau, Clinton K, O’Reilly, Francis J, Santhanam, Balaji, Lacey, Samuel E, Rappsilber, Juri, Carter, Andrew P
Format: Journal Article
Sprache:Englisch
Veröffentlicht: London Nature Publishing Group UK 15.04.2021
Springer Nature B.V
John Wiley and Sons Inc
Schlagworte:
Actin
Adapters
Adaptor proteins
Cargo
cargo adaptors
Coils
conservation
Cryoelectron Microscopy
cryo‐electron microscopy
Datasets
Domains
Dynactin
Dynactin Complex - chemistry
Dynactin Complex - metabolism
Dynein
Electron microscopy
EMBO05
EMBO40
Heat treating
Humans
Microtubules
Molecular Dynamics Simulation
Molecular motors
Molecular structure
protein complex
Protein Domains
Protein Multimerization
Protein Subunits - chemistry
Protein Subunits - metabolism
Signal classification
Subtraction
conservation
cryo‐electron microscopy
dynactin
protein complex
cargo adaptors
cryo-electron microscopy
ISSN:0261-4189, 1460-2075, 1460-2075
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Zusammenfassung:Dynactin is a 1.1 MDa complex that activates the molecular motor dynein for ultra‐processive transport along microtubules. In order to do this, it forms a tripartite complex with dynein and a coiled‐coil adaptor. Dynactin consists of an actin‐related filament whose length is defined by its flexible shoulder domain. Despite previous cryo‐EM structures, the molecular architecture of the shoulder and pointed end of the filament is still poorly understood due to the lack of high‐resolution information in these regions. Here we combine multiple cryo‐EM datasets and define precise masking strategies for particle signal subtraction and 3D classification. This overcomes domain flexibility and results in high‐resolution maps into which we can build the shoulder and pointed end. The unique architecture of the shoulder securely houses the p150 subunit and positions the four identical p50 subunits in different conformations to bind dynactin’s filament. The pointed end map allows us to build the first structure of p62 and reveals the molecular basis for cargo adaptor binding to different sites at the pointed end. Synopsis Cryo‐electron microscopy structures of dynactin’s shoulder and pointed end show the complex architecture of the shoulder domain and reveal how different adaptors bind to conserved sites on the pointed end. Combination of different dynactin cryo‐EM datasets and signal subtraction with optimized masks produce sidechain resolution structures of dynactin’s domains. The shoulder’s unique architecture leads to the anchoring of the p150 projection and the asymmetric presentation of the four p50 subunits. The pointed end structure reveals the conserved residues that interact with dynein’s cargo adaptors. Graphical Abstract Refinement of dynactin cryo‐EM structures offers insights into dynactin subunit organization in the shoulder region and adaptor binding to its pointed end.
Bibliographie:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
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ISSN:0261-4189
1460-2075
1460-2075
DOI:10.15252/embj.2020106164