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Reconstitution of Actin-Based Motility with Commercially Available Proteins
Published on: October 28, 2022
Dynamic nuclear actin assembly by Arp2/3 complex and a baculovirus WASP-like protein
Erin D Goley1, Taro Ohkawa, Joel Mancuso
1Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
Science (New York, N.Y.)
|October 21, 2006
Summary
Baculoviruses induce nuclear actin polymerization using the Arp2/3 complex and a viral protein (p78/83). This nuclear actin assembly is crucial for producing new virus particles and viral replication.
Area of Science:
- Virology
- Cell Biology
- Molecular Biology
Background:
- Pathogenic bacteria and viruses often manipulate host cell actin polymerization in the cytoplasm for infection.
- Nuclear actin dynamics are increasingly recognized for their roles in cellular processes, but their manipulation by viruses is less understood.
Purpose of the Study:
- To investigate a novel pathogenic mechanism involving dynamic actin assembly within the host cell nucleus.
- To elucidate the role of nuclear actin polymerization in baculovirus replication.
Main Methods:
- Utilized Autographa californica multiple nucleopolyhedrovirus (AcMNPV) infection models.
- Investigated the translocation of the host actin-nucleating Arp2/3 complex into the nucleus.
- Characterized the function of the viral Wiskott-Aldrich syndrome protein (WASP)-like protein p78/83 in activating nuclear actin assembly.
Main Results:
- Demonstrated that AcMNPV induces nuclear actin polymerization.
- Showed that the viral protein p78/83 activates the host Arp2/3 complex within the nucleus.
- Confirmed that nuclear actin assembly mediated by p78/83 and Arp2/3 is essential for viral progeny production.
Conclusions:
- Nuclear actin polymerization is a key pathogenic mechanism employed by baculoviruses.
- Viruses can manipulate host nuclear actin dynamics to facilitate their replication.
- This strategy of nuclear actin recompartmentalization may be a conserved viral pathogenesis mechanism.
Related Concept Videos
01:14Generation of Straight or Branched Actin Filaments
The straight or branched structure formation of actin filaments is controlled by nucleating proteins such as the formins and Arp2/3 complex. Formin-mediated assembly results in straight filaments, whereas Arp2/3 protein complex-mediated assembly results in branched actin filaments.
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...
01:11Formation of Higher-order Actin Filaments
The polymerization of G-actin monomers into filamentous F-actin is a multi-step process. Once the F-actins are formed, they can bundle together in different arrangements to form higher-order networks and regulate cellular functions. Common examples include the formation of lamellipodia and filopodia at the cell's leading edge by actin reorganization in a migrating cell. The microvilli on the brush border epithelial cells are also formed through the F-actin network.
The high-order actin networks...
The high-order actin networks...
01:39Mechanism of Filopodia Formation
Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
01:31Mechanism of Lamellipodia Formation
Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
01:42Actin Polymerization
Actin polymerization occurs through the head-to-tail association of binding sites on monomeric actin or G-actin to form filamentous or F-actin. The polymerization can be divided into three phases ̶ nucleation, elongation, and steady-state phase.
The nucleation phase involves forming a stable nucleus consisting of three actin monomers to form a new actin filament. Actin-binding proteins such as formins and Arp2/3 complex help filament growth post-nucleation. The Formins form straight actin...
The nucleation phase involves forming a stable nucleus consisting of three actin monomers to form a new actin filament. Actin-binding proteins such as formins and Arp2/3 complex help filament growth post-nucleation. The Formins form straight actin...
01:26Introduction to Actin
Actin is a highly conserved cytoskeletal protein found abundantly in eukaryotic cells. It constitutes 10% weight of the total cellular protein in muscle cells, while in non-muscle cells, it is lower and makes up around 1–5 percent of the total cell protein. Actin found in the unicellular amoebae and complex multicellular animals is around 80% similar, demonstrating their conservation over a billion years of evolution. Actin coding genes are conserved within species and across different species.