TRIM5 alpha cytoplasmic bodies are highly dynamic structures

Mol Biol Cell. 2007 Jun;18(6):2102-11. doi: 10.1091/mbc.e06-12-1075. Epub 2007 Mar 28.

Abstract

Tripartite motif (TRIM)5 alpha has recently been identified as a host restriction factor that has the ability to block infection by certain retroviruses in a species-dependent manner. One interesting feature of this protein is that it is localized in distinct cytoplasmic clusters designated as cytoplasmic bodies. The potential role of these cytoplasmic bodies in TRIM5 alpha function remains to be defined. By using fluorescent fusion proteins and live cell microscopy, we studied the localization and dynamics of TRIM5 alpha cytoplasmic bodies. This analysis reveals that cytoplasmic bodies are highly mobile, exhibiting both short saltatory movements and unidirectional long-distance movements along the microtubule network. The morphology of the cytoplasmic bodies is also dynamic. Finally, photobleaching and photoactivation analysis reveals that the TRIM5 alpha protein present in the cytoplasmic bodies is very dynamic, rapidly exchanging between cytoplasmic bodies and a more diffuse cytoplasmic population. Therefore, TRIM5 alpha cytoplasmic bodies are dynamic structures more consistent with a role in function or regulation rather than protein aggregates or inclusion bodies that represent dead-end static structures.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antiviral Restriction Factors
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Carrier Proteins / ultrastructure*
  • Cell Line
  • Cytoplasm / metabolism
  • Cytoskeleton / metabolism
  • Fluorescence Recovery After Photobleaching
  • Humans
  • Inclusion Bodies / metabolism
  • Inclusion Bodies / ultrastructure*
  • Microscopy, Fluorescence
  • Microtubules / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Tripartite Motif Proteins
  • Ubiquitin-Protein Ligases

Substances

  • Antiviral Restriction Factors
  • Carrier Proteins
  • Recombinant Fusion Proteins
  • Tripartite Motif Proteins
  • TRIM5 protein, human
  • Ubiquitin-Protein Ligases