The dimeric Golgi protein Gorab binds to Sas6 as a monomer to mediate centriole duplication
- University of Cambridge, United Kingdom
- Medical University of Vienna, Austria
- Institute of Biochemistry and Biophysics PAS, Poland
- University of Vienna, Austria
- California Institute of Technology, United States
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
Agnieszka Fatalska
Funding
Wellcome Trust (Investigator Award)
- David M Glover
National Institute of Neurological Disorders and Stroke (R01NS113930)
- David M Glover
National Science Centre (MAESTRO project UMO-2014/14/A/NZ1/00306)
- Agnieszka Fatalska
- Michal Dadlez
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.
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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