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TRIM5alpha selectively binds a restriction-sensitive retroviral capsid

Sarah Sebastian1, Jeremy Luban

  • 1Department of Microbiology, Columbia University, College of Physicians and Surgeons, 701 West 168th Street, HHSC 1502, New York, New York 10032, USA. ss2265@columbia.edu

Retrovirology
|June 22, 2005
PubMed

Insights

Tripartite motif-containing protein 5 alpha (TRIM5alpha) inhibits retroviruses by binding viral capsid residues. This binding, dependent on the SPRY domain, explains TRIM5alpha’s specific targeting of susceptible viruses.

Area of Science:

  • Virology
  • Immunology
  • Molecular Biology

Background:

  • Tripartite motif-containing protein 5 alpha (TRIM5alpha) is a key retroviral restriction factor in many primate species.
  • TRIM5alpha's C-terminal SPRY domain is crucial for its antiviral activity, but the precise mechanism of viral recognition remains unclear.

Purpose of the Study:

  • To elucidate the molecular mechanism by which TRIM5alpha recognizes and targets retroviruses for restriction.
  • To investigate the role of the SPRY domain in TRIM5alpha-mediated viral discrimination.

Main Methods:

  • Biochemical assays were used to study the interaction between TRIM5alpha and retroviral capsid (CA) proteins.
  • Experiments utilized detergent-stripped virions to isolate and analyze viral components.

Main Results:

  • TRIM5alpha directly binds to retroviral capsid (CA) proteins.
  • This binding interaction is dependent on the SPRY domain of TRIM5alpha.
  • The binding demonstrates high specificity, accurately discriminating between susceptible and non-susceptible viral capsids.

Conclusions:

  • TRIM5alpha's SPRY domain is essential for recognizing specific capsid residues on incoming retroviruses.
  • The direct, specific binding of TRIM5alpha to viral CA explains the precise targeting observed in retroviral restriction.
  • These findings provide a mechanistic basis for TRIM5alpha's potent antiviral activity.

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