Functional analysis on the interactions of the human immunodeficiency virus type 1 integrase with its cofactors that regulate viral replication
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Date
2008-11, 2010-03, 2011-03
Authors
Zheng, Yingfeng
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central Ltd
American Society for Biochemistry and Molecular Biology
American Society for Biochemistry and Molecular Biology
Abstract
Like all viruses, the replication of HIV-1 relies heavily on host proteins due to its limited genome products. HIV-1 integrase (IN) catalyzes the integration of viral DNA into host genome and also impacts other steps of viral replication cycle, all of which are assisted by various cellular proteins. Among them, LEDGF/p75 acts as the IN-to-chromatin tethering factor. However, whether other cellular cofactors also participate in this process still remains elusive. To gain insight into the mechanism of action of HIV-1 IN during viral integration, we used a previously described IN/yeast lethality system and our results revealed that the HIV-1 IN-induced yeast lethality absolutely required its chromatin binding ability. Since there is no yeast homolog of LEDGF/p75, it raises the possibility that IN may recruit other cellular cofactors for its chromatin targeting. Consistently, further analysis in mammalian cells indicated that HIV-1 IN was able to mediate chromatin binding independent of IN-LEDGF/p75 interaction and that HIV-1 fitness relied more on chromatin binding than LEDGF/p75 binding of IN. These data greatly enrich our current knowledge on the dynamic interplay within the ternary complex IN/LEDGF/chromatin.
HIV-1 exploits multiple cellular cofactors not only to facilitate viral replication, but also to evade the host defense system in favor of the virus. IN is known to be an unstable protein, degraded by the host ubiquitin-proteasome pathway. To investigate how IN avoids the host degradation machinery in the context of viral infection, we showed that IN interacted with host protein Ku70 and protected itself from the Lys48-linked polyubiquitination proteasomal pathway. More importantly, Ku70 was shown to be incorporated into the progeny virus in an IN-dependent manner, and both cell- and virus- associated Ku70 were essential for HIV-1 replication. Finally, the data demonstrated that the interactions between HIV-1 IN and host cofactors can be regulated through its SUMO-interacting motifs (SIMs). Three putative SIMs (72VILV75; 200IVDI203 and 257IKII260) in IN were examined and shown to be essential for IN-LEDGF/p75 but not IN-Ku70 interaction.
In summary, this study advances our knowledge of the interaction network between IN and its cofactors, which would have important implications for the design of anti-HIV drugs.
Description
Keywords
HIV-1 integrase, protein-protein interaction, LEDGF/p75, Ku70
Citation
Xu Z, Zheng Y, Ao Z, Clement M, Mouland AJ, Kalpana GV, Belhumeur P, Cohen EA, Yao X: Contribution of the C-terminal region within the catalytic core domain of HIV-1 integrase to yeast lethality, chromatin binding and viral replication. Retrovirology 2008, 5:102.
Zheng Y, Ao Z, Jayappa KD, Yao X: Characterization of the HIV-1 integrase chromatin- and LEDGF/p75-binding abilities by mutagenic analysis within the catalytic core domain of integrase. Virol J 2010, 7:68.
Zheng Y, Ao Z, Wang B, Jayappa KD, Yao X: Host protein Ku70 binds and protects HIV-1 integrase from proteasomal degradation and is required for HIV replication. J Biol Chem 2011, 286:17722-17735.
Zheng Y, Ao Z, Jayappa KD, Yao X: Characterization of the HIV-1 integrase chromatin- and LEDGF/p75-binding abilities by mutagenic analysis within the catalytic core domain of integrase. Virol J 2010, 7:68.
Zheng Y, Ao Z, Wang B, Jayappa KD, Yao X: Host protein Ku70 binds and protects HIV-1 integrase from proteasomal degradation and is required for HIV replication. J Biol Chem 2011, 286:17722-17735.