Patching up the nucleus: a novel role for PMLII in nuclear envelope stability
Anne F J Janssen1,2, Oliver Knowles1, Sébastien Britton3
1Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, United Kingdom.
Nucleic Acids Research
|July 16, 2026
Summary
Promyelocytic leukemia protein isoform II (PMLII) forms nuclear envelope (NE) patches at sites of lamina disruption. These PMLII patches stabilize large NE holes, suggesting a role in maintaining nuclear envelope integrity during cellular stress.
Area of Science:
- Cell Biology
- Molecular Biology
- Genomics
Background:
- The nuclear envelope (NE) is crucial for genome protection and organization.
- NE dynamics, including rupture and repair, are vital for cellular processes.
- Events preceding NE rupture remain poorly understood.
Purpose of the Study:
- Investigate the role of promyelocytic leukemia protein isoform II (PMLII) in NE dynamics.
- Determine the function of PMLII condensates at the nuclear envelope.
- Elucidate PMLII's contribution to nuclear envelope integrity.
Main Methods:
- Live-cell imaging to observe NE dynamics and PMLII localization.
- Utilizing stable cell lines with FLAG-PMLII expression in a PML knockdown background.
- Analyzing the impact of PMLII on lamina hole size and NE rupture frequency.
Main Results:
- PMLII forms condensates at the NE, specifically at sites of lamina disruption.
- Two amphipathic α-helices in PMLII's C-terminus are essential for NE localization.
- PMLII patches persist at rupture sites until repair initiation.
- PMLII increases lamin hole size without increasing NE rupture frequency.
Conclusions:
- PMLII condensates play a role in NE integrity maintenance.
- PMLII stabilizes large holes in the lamina, contributing to NE dynamics.
- Further research into PMLII's function in NE repair is warranted.
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