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Trafficking of some old world primate TRIM5α proteins through the nucleus

Felipe Diaz-Griffero1, Daniel E Gallo, Thomas J Hope

  • 1Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.

Retrovirology
|May 18, 2011
PubMed
Abstract

Insights

Human and rhesus TRIM5α proteins traffic to the nucleus, a novel finding that may reveal new functions for these retroviral restriction factors. This nuclear transport is reversible and impacts TRIM5α localization.

Area of Science:

  • Virology
  • Cell Biology
  • Immunology

Background:

  • TRIM5α and TRIMCyp are cytoplasmic proteins crucial for early retroviral infection blocks.
  • TRIM5 proteins typically form dynamic cytoplasmic bodies.
  • Other TRIM family proteins are known to localize to the nucleus.

Purpose of the Study:

  • To investigate nuclear trafficking of TRIM5α proteins.
  • To determine the impact of nuclear transport on retroviral restriction.

Main Methods:

  • Studied TRIM5α protein localization in human and rhesus monkey cells.
  • Utilized leptomycin B treatment to analyze nuclear-cytoplasmic shuttling.
  • Investigated the effect of amino-terminal deletions on TRIM5α localization.
  • Assessed retroviral restriction in treated and untreated cells.

Main Results:

  • TRIM5α proteins from humans and rhesus monkeys shuttle between the cytoplasm and nucleus.
  • Nuclear import/export is mediated by a leptomycin B-sensitive mechanism.
  • Leptomycin B treatment causes TRIM5α to form nuclear bodies with TRIM19 (PML).
  • Amino-terminal deletions lead to TRIM5α accumulation in nuclear bodies.
  • Nuclear shuttling had minimal impact on retroviral restriction.

Conclusions:

  • Human and rhesus TRIM5α proteins exhibit novel nuclear trafficking capabilities.
  • This previously unknown shuttling mechanism may indicate an undiscovered function for TRIM5α.

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