The dimeric Golgi protein Gorab binds to Sas6 as a monomer to mediate centriole duplication
Abstract
The duplication and 9-fold symmetry of the Drosophila centriole requires that the cartwheel molecule, Sas6, physically associates with Gorab, a trans-Golgi component. How Gorab achieves these disparate associations is unclear. Here we use hydrogen-deuterium exchange mass spectrometry to define Gorab's interacting surfaces that mediate its sub-cellular localization. We identify a core stabilization sequence within Gorab's C-terminal coiled-coil domain that enables homodimerization, binding to Rab6, and thereby trans-Golgi localization. By contrast, part of the Gorab monomer's coiled-coil domain undergoes an anti-parallel interaction with a segment of the parallel coiled-coil dimer of Sas6. This stable hetero-trimeric complex can be visualized by electron microscopy. Mutation of a single leucine residue in Sas6's Gorab-binding domain generates a Sas6 variant with a 16-fold reduced binding affinity for Gorab that can not support centriole duplication. Thus Gorab dimers at the Golgi exist in equilibrium with Sas-6 associated monomers at the centriole to balance Gorab's dual role.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files.
Article and author information
Author details
Funding
National Science Centre (MAESTRO (UMO-2014/14/A/NZ1/00306))
- Agnieszka Fatalska
- Michal Dadlez
Wellcome Trust
- Agnieszka Fatalska
- Magdalena Richter
- Levente Kovacs
Austrian Science Fund (P28231-B28)
- Gang Dong
Austrian Science Fund (W-1258 Doktoratskollegs)
- Emma Stepinac
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Anna Akhmanova, Utrecht University, Netherlands
Version history
- Received: March 26, 2020
- Accepted: March 11, 2021
- Accepted Manuscript published: March 11, 2021 (version 1)
- Accepted Manuscript updated: March 12, 2021 (version 2)
- Accepted Manuscript updated: March 12, 2021 (version 3)
- Version of Record published: March 30, 2021 (version 4)
Copyright
© 2021, Fatalska et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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