Intracellular Movement of Viruses and Bacteria

When viruses and bacteria enter a eukaryotic host cell, their free movement is hindered by the viscous cytosol containing organelles and protein complexes.

These organisms move around in host cells with the help of cytoskeletal proteins such as actins and tubulins.

In actin polymerization-based movement, a bacterium expresses a surface protein at its one end that activates the Arp2/3 complex, which then initiates the assembly of the host actin filaments as tails.

The growing tails generate a thrust that allows the bacterium to move forward within the cell.

In microtubule-motor protein-based movement, the viruses enter the neurons from the axon tips, and lose their lipid envelope. The protein coated viral particle is carried by dynein motor proteins into the nucleus.

After replicating within the nucleus, the virus particles are carried to the axonal tip by the kinesin motor proteins. These virus particles are then released outside, or they move into the neighboring cells.