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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
Summary
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.