Structural basis for the phase separation of the chromosome passenger complex
- University of Pennsylvania, United States
- University of Virginia, United States
Abstract
The physical basis of phase separation is thought to consist of the same types of bonds that specify conventional macromolecular interactions yet is unsatisfyingly often referred to as 'fuzzy'. Gaining clarity on the biogenesis of membraneless cellular compartments is one of the most demanding challenges in biology. Here, we focus on the chromosome passenger complex (CPC), that forms a chromatin body that regulates chromosome segregation in mitosis. Within the three regulatory subunits of the CPC implicated in phase separation - a heterotrimer of INCENP, Survivin, and Borealin - we identify the contact regions formed upon droplet formation using hydrogen/deuterium-exchange mass spectrometry (HXMS). These contact regions correspond to some of the interfaces seen between individual heterotrimers within the crystal lattice they form. A major contribution comes from specific electrostatic interactions that can be broken and reversed through initial and compensatory mutagenesis, respectively. Our findings reveal structural insight for interactions driving liquid-liquid demixing of the CPC. Moreover, we establish HXMS as an approach to define the structural basis for phase separation.
Data availability
Source data are provided with this paper. The HXMS data in this study has been deposited in the Pride database under accession code PXD034374. The structure 2QFA [https://doi.org/10.2210/pdb2QFA/pdb] from the Protein Data Bank (www.rcsb.org) was used inthis study. An AlphaFold prediction for the Borealin protein (primary accession number Q53HL2) was used in this study.
Article and author information
Author details
Funding
National Institute of General Medical Sciences (GM130302)
- Ben E Black
National Institute of General Medical Sciences (GM134591)
- Nikaela W Bryan
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2024, Bryan 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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Structural basis for the phase separation of the chromosome passenger complex
eLife 13:e92709.
https://doi.org/10.7554/eLife.92709
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