Actin Dynamics and Isoform Functionality in Cellular Processes

Actin is a fundamental cytoskeletal protein that assembles into dynamic filaments to drive essential cellular behaviours such as motility, division and intracellular transport. In mammalian cells, multiple actin isoforms coexist, with non-muscle β- and γ-actin being predominant in most tissues. Although these isoforms differ by only a few amino acids, they exhibit distinct polymerisation kinetics, mechanical properties and patterns of subcellular localisation. Actin filaments (F-actin) dynamically interconvert with globular actin monomers (G-actin) under the control of actin-binding proteins (ABPs) and ion concentrations, generating networks of varying stiffness and contractile capacity. Spatial and temporal regulation of filament nucleation, elongation and crosslinking underpins processes ranging from the formation of the cytokinetic contractile ring to the protrusive forces at the leading edge of migrating cells. Isoform-specific interactions with ABPs and motor proteins further tune filament architecture, allowing cells to tailor mechanical output and signal transduction in development, tissue homeostasis and disease.

Research from Nature Portfolio

Recent studies have demonstrated that β- and γ-actin form networks with distinct rheological signatures. γ-Actin networks exhibit greater stiffness and form larger contraction foci in the presence of myosin, whereas β-actin networks generate more numerous but smaller foci. These differences arise from isoform-specific interactions with divalent cations and crosslinking partners, suggesting that minor sequence variations can remodel network mechanics to suit specialised functions in epithelial and mesenchymal contexts.

Investigations into cytokinesis have revealed that an anillin-mediated pathway selectively nucleates β-actin filaments at the cleavage furrow. RhoA-dependent activation of the formin DIAPH3 produces homopolymeric β-actin arrays that stabilise the contractile ring. This isoform-specific assembly mechanism ensures precise spatial control of cytokinetic machinery and highlights how cells harness individual actin variants for discrete morphogenetic tasks.

Actin Dynamics and Isoform Functionality in Cellular Processes publication trend

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

Technical terms

Isoform: A variant of a protein that arises from a single gene family but differs slightly in amino acid sequence and functional properties.

F-actin: Filamentous polymer of actin subunits formed by the assembly of G-actin monomers.

G-actin: Globular, monomeric form of actin that can polymerise into F-actin.

Rheology: The study of the flow and deformation behaviour of materials, applied here to assess filament network mechanics.

Actin-binding protein (ABP): A protein that interacts with actin monomers or filaments to regulate assembly, stability and organisation.

References

1. Cytosolic actin isoforms form networks with different rheological properties that indicate specific biological function. Nature Communications (2023).
2. Cytokinesis requires localized β-actin filament production by an actin isoform specific nucleator. Nature Communications (2017).
3. IntAct: A nondisruptive internal tagging strategy to study the organization and function of actin isoforms. PLOS Biology (2024).
4. Insights into Actin Isoform-Specific Interactions with Myosin via Computational Analysis. Molecules (2024).
5. The Role of non-muscle actin paralogs in cell cycle progression and proliferation. European Journal of Cell Biology (2023).