Research

Cyclophilin A interacts with diverse lentiviral capsids

Tsai-Yu Lin¹ and Michael Emerman^1,2

¹  Pathobiology Graduate Program, University of Washington, Seattle, WA 98195, USA

²  Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA

author email corresponding author email

Retrovirology 2006, 3:70doi:10.1186/1742-4690-3-70

Published:	12 October 2006

Abstract

Background

The capsid (CA) protein of HIV-1 binds with high affinity to the host protein cyclophilin A (CypA). This binding positively affects some early stage of the viral life-cycle because prevention of binding either by drugs that occupy that active site of cyclophilin A, by mutation in HIV-1 CA, or RNAi that knocks down intracellular CypA level diminishes viral infectivity. The closely related lentivirus, SIVcpz also binds CypA, but it was thought that this interaction was limited to the HIV-1/SIVcpz lineage because other retroviruses failed to interact with CypA in a yeast two-hybrid assay.

Results

We find that diverse lentiviruses, FIV and SIVagmTAN also bind to CypA. Mutagenesis of FIV CA showed that an amino acid that is in a homologous position to the proline at amino acid 90 of HIV-1 CA is essential for FIV interactions with CypA.

Conclusion

These results demonstrate that CypA binding to lentiviruses is more widespread than previously thought and suggest that this interaction is evolutionarily important for lentiviral infection.