TRIM37 is an E3 ubiquitin ligase mutated in Mulibrey nanism, a disease with impaired organ growth and increased tumor formation. TRIM37 depletion from tissue culture cells results in supernumerary foci bearing the centriolar protein Centrin. Here, we characterize these centriolar protein assemblies (Cenpas) to uncover the mechanism of action of TRIM37. We find that an atypical de novo assembly pathway can generate Cenpas that act as microtubule organizing centers (MTOCs), including in Mulibrey patient cells. Correlative light electron microscopy reveals that Cenpas are centriole-related or electron-dense structures with stripes. TRIM37 regulates the stability and solubility of Centrobin, which accumulates in elongated entities resembling the striped electron dense structures upon TRIM37 depletion. Furthermore, Cenpas formation upon TRIM37 depletion requires PLK4, as well as two parallel pathways relying respectively on Centrobin and PLK1. Overall, our work uncovers how TRIM37 prevents Cenpas formation, which would otherwise threaten genome integrity, including in Mulibrey patients.
All data generated or analysed during this study are included in the manuscript and supporting files.
- Pierre Gönczy
- Fernando R Balestra
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Human subjects: Fibroblast cultures were established from skin biopsy samples with approval by the Institutional Review Board of the Helsinki University Central Hospital (183/13/03/03/2009). The patients signed an informed consent for the use of fibroblast cultures.
- Jens Lüders, Institute for Research in Biomedicine, Spain
© 2021, Balestra et al.
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