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

Clinton K. Lau, Francis J. O’Reilly, Balaji Santhanam, Samuel E. Lacey, Juri Rappsilber, Andrew P. Carter*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
Article numbere106164
Number of pages19
JournalEMBO Journal
Volume40
Issue number8
DOIs
Publication statusPublished - 18 Mar 2021

Keywords

  • cargo adaptors
  • conservation
  • cryo-electron microscopy
  • dynactin
  • protein complex

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