Related Experiment Video
Updated: Jun 17, 2025
Method for Measurement of Viral Fusion Kinetics at the Single Particle Level
Published on: September 7, 2009
Revealing Different Pathways for Influenza A Virus To Reach Microtubules after Endocytosis by Quantum Dot-Based
Lei Du1, Yi-Ning Hou1, Dan-Dan Fu1
1College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P.R. China.
Abstract:
Actin- and microtubule (MT)-based transport systems are essential for intracellular transport. During influenza A virus (IAV) infection, MTs provide long tracks for virus trafficking toward the nucleus. However, the role of the actin cytoskeleton in IAV entry and especially the transit process is still ambiguous. Here, by using quantum dot-based single-virus tracking, it was revealed that the actin cytoskeleton was crucial for the virus entry via clathrin-mediated endocytosis (CME). After entry via CME, the virus reached MTs through three different pathways: the virus (1) was driven by myosin VI to move along actin filaments to reach MTs (AF); (2) was propelled by actin tails assembled by an Arp2/3-dependent mechanism to reach MTs (AT); and (3) directly reached MTs without experiencing actin-related movement (NA). Therefore, the NA pathway was the main one and the fastest for the virus to reach MTs. The AT pathway was activated only when plenty of viruses entered the cell. The viruses transported by the AF and AT pathways shared similar moving velocities, durations, and displacements. This study comprehensively visualized the role of the actin cytoskeleton in IAV entry and transport, revealing different pathways for IAV to reach MTs after entry. The results are of great significance for globally understanding IAV infection and the cellular endocytic transport pathway.
Insights
Influenza A virus uses actin and microtubules for intracellular transport. This study reveals three distinct pathways for virus transport to microtubules after entry, with direct microtubule access being the fastest.
Area of Science:
- Cell Biology
- Virology
- Cytoskeletal Dynamics
Background:
- Microtubules are known to facilitate influenza A virus (IAV) trafficking within host cells.
- The precise role of the actin cytoskeleton in IAV entry and intracellular transit remains unclear.
Purpose of the Study:
- To elucidate the function of the actin cytoskeleton in IAV entry and transport.
- To identify and characterize the pathways IAV utilizes to reach microtubules post-entry.
Main Methods:
- Utilized quantum dot-based single-virus tracking to visualize IAV movement.
- Investigated the involvement of actin-related mechanisms and clathrin-mediated endocytosis (CME).
Main Results:
- Confirmed actin cytoskeleton's crucial role in IAV entry via CME.
- Identified three distinct post-entry transport pathways to microtubules: actin filament-dependent (AF), actin tail-dependent (AT), and no actin-related movement (NA).
- The NA pathway was the predominant and fastest route; the AT pathway was induced during high viral load.
Conclusions:
- The actin cytoskeleton plays a multifaceted role in IAV infection, influencing entry and mediating distinct transport routes to microtubules.
- Understanding these pathways offers critical insights into IAV pathogenesis and cellular endocytic transport mechanisms.
