Role of SUMO-1 and SUMO interacting motifs in rhesus TRIM5α-mediated restriction.
BACKGROUND
TRIM5α is a member of the tripartite motif family of proteins that restricts retroviral infection in a species-specific manner. The restriction requires an interaction between the viral capsid lattice and the B30.2/SPRY domain of TRIM5α. Previously, we determined that two SUMO interacting motifs (SIMs) present in the B30.2/SPRY domain of human TRIM5α (huTRIM5α) were important for the restriction of N-tropic Murine Leukemia Virus. Here, we examined whether SUMO expression and the SIM1 and SIM2 motifs in rhesus monkey TRIM5α (rhTRIM5α) are similarly important for Human Immunodeficiency Type 1 (HIV-) restriction.


RESULTS
We found that mutation of SIM1 and SIM2 of rhTRIM5α abolished the restriction of HIV-1 virus. Further, knockdown of SUMO-1 in rhTRIM5α expressing cells abolished restriction of HIV-1. These results may be due, in part, to the ability of SUMO-1 to stabilize rhTRIM5α protein expression, as SUMO-1 knockdown increased rhTRIM5α turnover and the mutations in SIM1 and SIM2 led to more rapid degradation than the wild type protein. The NF-κB signaling ability of rhTRIM5α was also attenuated by SUMO-1 knockdown. Finally, upon inhibition of CRM1-dependent nuclear export with Leptomycin B (LMB), wild type rhTRIM5α localized to SUMO-1 bodies in the nucleus, while the SIM1 and SIM2 mutants did not localize to SUMO-1.


CONCLUSIONS
Our results suggest that the rhTRIM5α B30.2/SPRY domain is not only important for the recognition of the HIV-1 CA, but it is also important for its association with SUMO-1 or SUMO-1 modified proteins. These interactions help to maintain TRIM5α protein levels and its nuclear localization into specific nuclear bodies.
Department of Microbiology and Immunology Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
Zana
Z
Lukic
Stephen P
SP
Goff
Edward M
EM
Campbell
Gloria
G
Arriagada
D002460:Cell Line; D004252:DNA Mutational Analysis; D055785:Gene Knockdown Techniques; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D011506:Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D025842:SUMO-1 Protein / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases
D016328:NF-kappa B; D011506:Proteins; D025842:SUMO-1 Protein; C482587:TRIM5(alpha) protein, rhesus monkey; D044767:Ubiquitin-Protein Ligases