Rotavirus assembly: an alternative model that utilizes an atypical trafficking pathway.

Area of Science:

• Virology
• Cell Biology
• Molecular Biology

Background:

• Rotavirus assembly is traditionally studied in MA104 kidney cells, suggesting endoplasmic reticulum (ER) involvement and cell lysis for release.
• Recent findings in intestinal cells propose an alternative rotavirus assembly and release mechanism.

Purpose of the Study:

• To review recent advances in understanding rotavirus and rotaviral protein trafficking and assembly within intestinal cells.
• To highlight differences in rotavirus assembly pathways between intestinal and kidney epithelial cells.

Main Methods:

• Review of existing data on rotavirus assembly in intestinal cells.
• Analysis of protein interactions, specifically VP4 with cellular components and membrane microdomains.
• Investigation of polarized trafficking pathways in infected intestinal cells.

Main Results:

• Rotavirus assembly in intestinal cells appears to finalize outside the ER, with apical release and minimal cell lysis.
• Key viral protein VP4 interacts with cholesterol- and sphingolipid-rich membrane rafts.
• VP4 does not localize to the ER or Golgi in infected intestinal cells, suggesting an atypical trafficking route.

Conclusions:

• Rotavirus assembly in intestinal cells follows a distinct pathway compared to kidney cells.
• This pathway is raft-dependent, involves VP4 targeting to the apical membrane, and bypasses the classical exocytic route.
• Interactions with cellular proteins like Hsp70 and cytoskeletal components are crucial for this atypical polarized trafficking.