Actin on DNA—An ancient and dynamic relationship

  title={Actin on DNA—An ancient and dynamic relationship},
  author={Kari-Pekka Skarp and Maria K. Vartiainen},
In the cytoplasm of eukaryotic cells the coordinated assembly of actin filaments drives essential cell biological processes, such as cell migration. The discovery of prokaryotic actin homologues, as well as the appreciation of the existence of nuclear actin, have expanded the scope by which the actin family is utilized in different cell types. In bacteria, actin has been implicated in DNA movement tasks, while the connection with the RNA polymerase machinery appears to exist in both prokaryotes… 

The long journey: actin on the road to pro- and eukaryotic cells.

It is assumed that an ancestor of actin/MreB/ParM already existed in the last common progenitor of all cells, and various aspects on how actins may have found their way into bacteria, into the eukaryotic cytoplasm and into the nuclear compartment are discussed.

Co-transcriptional nuclear actin dynamics

By focusing on the multiple tasks performed by actin and actin-binding proteins, possible models of how actin dynamics controls the different phases of the RNA polymerase II transcription cycle are being identified.

Active maintenance of nuclear actin by importin 9 supports transcription

It is demonstrated that cytoplasmic and nuclear actin pools are dynamically connected and the nuclear import and export mechanisms of actin are identified, which suggest an active transport mechanism in both directions.

β- and γ-Actins in the nucleus of human melanoma A375 cells

It is shown that, in contrast to the cytoplasm, the majority of endogenous nuclear actin is unpolymerized in human melanoma A375 cells, and β- and γ-non-muscle actin isoforms are present in nuclei of these cells.

Actin Folding, Structure and Function: Is It a Globular or an Intrinsically Disordered Protein?

Investigation of muscle actin focused on its ability to polymerize and to interact with the other main muscle protein, myosin, and several other regulatory proteins that control muscle relaxation and contraction, and showed that actin participates in many other vitally important cellular processes.

Identification of Evolutionarily Conserved Nuclear Matrix Proteins and Their Prokaryotic Origins.

This study addresses the issue using the developing embryos of Drosophila melanogaster and Danio rerio and identifies 362 core NuMat proteins that are conserved between the two organisms, indicating their indispensable nature for nuclear function for over 1.5 billion years of eukaryotic history.

Actin as a model for the study of nucleocytoplasmic shuttling and nuclear dynamics.

Live-cell imaging assays based on fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobLEaching (FLIP) for monitoring both import and export of fluorescently labelled molecules.

Nuclear F-actin Formation and Reorganization upon Cell Spreading*♦

The results reveal a signaling pathway, which links integrin activation by extracellular matrix interaction to nuclear actin polymerization through the LINC complex, and therefore suggest a role for nuclear act in polymerization in the context of cellular adhesion and mechanosensing.

The role of exportin 6 in cytoskeletal-mediated cell death and cell adhesion in human non-small-cell lung carcinoma cells following doxorubicin treatment.

It is shown that downregulation of exportin 6 induced necrotic cell death and the observed alterations of cell adhesion suggest the key role of cytoplasmic F-actin in maintaining intercellular junctional complexes and/or focal adhesion properties and the importance of the balance between nuclear and cy toplasmics F- actin pools.

Functional evolution of nuclear structure

There is now strong evidence that nuclear pore complexes (NPCs) and nuclear membranes coevolved with the endomembrane system, and that the last eukaryotic common ancestor (LECA) had fully functional NPCs.



Prokaryotic origin of the actin cytoskeleton

It is demonstrated that the bacterial MreB protein assembles into filaments with a subunit repeat similar to that of F-actin—the physiological polymer of eukaryotic actin, demonstrating that M reB and actin are very similar in three dimensions.

Evolution of the gelsolin family of actin‐binding proteins as novel transcriptional coactivators

There is a growing body of evidence supporting a biological role in the nucleus for actin, Arps and actin‐binding proteins and, in particular, the gelsolin family of actin-binding proteins BioEssays 27:388–396, 2005.

The long journey of actin and actin-associated proteins from genes to polysomes

  • P. Percipalle
  • Biology, Chemistry
    Cellular and Molecular Life Sciences
  • 2009
Evidence on the involvement of actin and actin-associated proteins in RNA biogenesis is presented and integrative models supporting the view that actin facilitates coordination of the different steps in gene expression are proposed.

An actin–ribonucleoprotein interaction is involved in transcription by RNA polymerase II

The results indicate that an actin-based mechanism is implicated in the transcription of most if not all RNA polymerase II genes and suggest that anActin–hrp65-2 interaction is required to maintain the normal transcriptional activity of the cell.

p53-cofactor JMY is a Multifunctional Actin Nucleation Factor

JMY represents a new class of multifunctional actin assembly factor whose activity is regulated, at least in part, by sequestration in the nucleus.

The actin-like MreB cytoskeleton organizes viral DNA replication in bacteria

It is shown that the actin-like MreB cytoskeleton of the distantly related bacteria Escherichia coli and Bacillus subtilis is required for efficient viral DNA replication and a mechanism by which viralDNA replication is organized at the bacterial membrane is described.

Nucleoplasmic β-actin exists in a dynamic equilibrium between low-mobility polymeric species and rapidly diffusing populations

This work defines the dynamic properties of nuclear actin molecules using fluorescence recovery after photobleaching and confirms previous reports of polymeric forms ofnuclear actin observed in fixed specimens and reveals that these polymeric form are very dynamic.