Nuclear Actin Dynamics and Function

Actin, traditionally associated with the cytoskeleton, also assembles within the nucleus in response to developmental cues, stress and signalling pathways. Nuclear actin exists in monomeric (G-actin) and polymeric (F-actin) forms, dynamically regulated by import–export factors, nucleators and actin-binding proteins. These intranuclear filaments and oligomers contribute to chromatin remodelling, transcriptional regulation, DNA repair and genome organisation by providing structural scaffolds and facilitating the spatial movement of genomic loci. The balance between polymerisation and depolymerisation modulates histone modifications, gene accessibility and the clustering of transcriptional machinery, linking mechanical cues and extracellular signals to nuclear functions. Dysregulation of nuclear actin dynamics has been implicated in pathological processes including impaired differentiation, oncogenic transformation and inflammatory disease, emphasising its emerging role as a key regulator of nuclear architecture and cellular fate.

Research from Nature Portfolio

Recent studies have established that polymerised β-actin networks within the nucleus critically influence chromatin accessibility. Targeted inhibition of Arp2/3-dependent branching remodels pericentric heterochromatin marks and alters global accessibility patterns, while perturbation of actin nucleation can change differentiation trajectories in mesenchymal stem cells. Another set of findings revealed that physiological ligands for G protein-coupled receptors trigger rapid nuclear F-actin assembly via calcium release and recruitment of the formin INF2 at the inner nuclear membrane. This signal-dependent polymerisation emanates from the nuclear envelope towards the nuclear interior, promoting the clustering of active RNA polymerase II and rapid reorganisation of chromatin domains in response to extracellular cues.

Nuclear Actin Dynamics and Function publication trend

The graph below shows the total number of articles in nuclear actin dynamics and function across all publications each year (not limited to Nature Index journals).

Technical terms

Nuclear actin filament: A polymerised chain of actin subunits within the nucleus, contributing to chromatin organisation and nuclear mechanics.

G-actin: Globular, monomeric form of actin that serves as the building block for filament formation.

F-actin: Filamentous, polymerised form of actin that provides structural scaffolding within the nucleus.

Arp2/3 complex: A seven-subunit protein assembly that nucleates branched actin filament networks.

Formin: A family of proteins that facilitates the nucleation and elongation of linear actin filaments.

Chromatin accessibility: The degree to which DNA is exposed and available for interactions with transcription factors and repair machinery.

Epithelial–mesenchymal transition (EMT): A biological programme in which epithelial cells acquire migratory and invasive mesenchymal characteristics.

References

1. Nuclear actin structure regulates chromatin accessibility. Nature Communications (2024).
2. SUN2 mediates calcium-triggered nuclear actin polymerization to cluster active RNA polymerase II. EMBO Reports (2024).
3. Nuclear Actin Polymerization Regulates Cell Epithelial‐Mesenchymal Transition. Advanced Science (2023).
4. Aggravated Ulcerative Colitis via circNlgn-Mediated Suppression of Nuclear Actin Polymerization. Research (2024).
5. Loss of p53 function promotes DNA damage-induced formation of nuclear actin filaments. Cell Death & Disease (2023).