Engelman Lab
Mechanisms and Inhibition of HIV Nuclear Trafficking and Viral DNA Integration
The Engelman lab studies the modalities of HIV integrase and capsid proteins in viral replication with the long-term goal of novel target discovery for therapy-based intervention.
Integration of retroviral reverse transcripts into host chromosomal DNA is essential for viral replication, making the HIV integrase protein a high value antiviral target. Indeed, integrase strand transfer inhibitors are critical components of front-line formulations to treat people living with HIV (1). The Engelman lab uses a large swath of techniques including structural biology, genetics, biochemistry, virology, cellular biology, and bioinformatics to analyze the mechanisms of retroviral DNA integration and the roles of integrase and capsid proteins in viral replication. Particular emphasis is placed on virus-host interactions in HIV nuclear import and the trafficking of the viral preintegration complex to sites of integration (2, 3).
HIV preferentially integrates into active regions of human chromatin, which is in large part mediated by interactions between the integrase and capsid proteins with cognate cellular factors (4). Working with colleagues from Emory University, the Engelman lab determined that preintegration complexes congregate in cell nuclei with nuclear speckles for integration into nearby speckle-associated domains (SPADs) (3). The interaction of capsid with cleavage and polyadenylation specificity factor 6 (CPSF6) enables the preintegration complex to move beyond the nuclear periphery to encounter SPADs for integration (3, 5). The interaction of integrase with cellular transcriptional co-activator lens epithelium-derived growth factor (LEDGF)/p75 drives integration to the mid-regions of active genes (4, 6). Small molecule inhibitors of the LEDGF/p75-integrase interaction have been developed and are highly potent antivirals (1). Such compounds promote aberrant integrase multimerization in a LEDGF/p75-independent manner, and their antiviral potencies accordingly are independent of cellular LEDGF/p75 expression. The Engelman lab was one of several groups to demonstrate that these inhibitors block virus particle maturation, which was a highly unanticipated finding (7). This work highlighted a role for integrase in HIV maturation, and ongoing projects seek to further develop this inhibitor class. We also investigate the roles of integrase proteins in the maturation steps of other retroviruses.
Integration of retroviral reverse transcripts into host chromosomal DNA is essential for viral replication, making the HIV integrase protein a high value antiviral target. Indeed, integrase strand transfer inhibitors are critical components of front-line formulations to treat people living with HIV (1). The Engelman lab uses a large swath of techniques including structural biology, genetics, biochemistry, virology, cellular biology, and bioinformatics to analyze the mechanisms of retroviral DNA integration and the roles of integrase and capsid proteins in viral replication. Particular emphasis is placed on virus-host interactions in HIV nuclear import and the trafficking of the viral preintegration complex to sites of integration (2, 3).
HIV preferentially integrates into active regions of human chromatin, which is in large part mediated by interactions between the integrase and capsid proteins with cognate cellular factors (4). Working with colleagues from Emory University, the Engelman lab determined that preintegration complexes congregate in cell nuclei with nuclear speckles for integration into nearby speckle-associated domains (SPADs) (3). The interaction of capsid with cleavage and polyadenylation specificity factor 6 (CPSF6) enables the preintegration complex to move beyond the nuclear periphery to encounter SPADs for integration (3, 5). The interaction of integrase with cellular transcriptional co-activator lens epithelium-derived growth factor (LEDGF)/p75 drives integration to the mid-regions of active genes (4, 6). Small molecule inhibitors of the LEDGF/p75-integrase interaction have been developed and are highly potent antivirals (1). Such compounds promote aberrant integrase multimerization in a LEDGF/p75-independent manner, and their antiviral potencies accordingly are independent of cellular LEDGF/p75 expression. The Engelman lab was one of several groups to demonstrate that these inhibitors block virus particle maturation, which was a highly unanticipated finding (7). This work highlighted a role for integrase in HIV maturation, and ongoing projects seek to further develop this inhibitor class. We also investigate the roles of integrase proteins in the maturation steps of other retroviruses.
- Engelman AN. Multifaceted HIV integrase functionalities and therapeutic strategies for their inhibition. J Biol Chem 2019 Oct 11;294(41):15137-15157. PubMed PMID: 31467082.
- Matreyek KA, Yücel SS, Li X, Engelman A. Nucleoporin NUP153 phenylalanine-glycine motifs engage a common binding pocket within the HIV-1 capsid protein to mediate lentiviral infectivity. PLoS Pathog 2013;9(10):e1003693. PubMed PMID: 24130490.
- Francis AC, Marin M, Singh PK, Achuthan V, Prellberg MJ, Palermino-Rowland K, Lan S, Tedbury PR, Sarafianos SG, Engelman AN, Melikyan GB. HIV-1 replication complexes accumulate in nuclear speckles and integrate into speckle-associated genomic domains. Nat Commun 2020 Jul 14;11(1):3505. PubMed PMID: 32665593.
- Sowd GA, Serrao E, Wang H, Wang W, Fadel HJ, Poeschla EM, Engelman AN. A critical role for alternative polyadenylation factor CPSF6 in targeting HIV-1 integration to transcriptionally active chromatin. Proc Natl Acad Sci U S A 2016 Feb 23;113(8):E1054-E1063. PubMed PMID: 26858452.
- Achuthan V, Perreira JM, Sowd GA, Puray-Chavez M, McDougall WM, Paulucci-Holthauzen A, Wu X, Fadel HJ, Poeschla EM, Multani AS, Hughes SH, Sarafianos SG, Brass AL, Engelman AN. Capsid-CPSF6 interaction licenses nuclear HIV-1 trafficking to sites of viral DNA integration. Cell Host Microbe 2018 Sep 12;24(3):392-404.e8. PubMed PMID: 30173955.
- Singh PK, Plumb MR, Ferris AL, Iben JR, Wu X, Fadel HJ, Luke BT, Esnault C, Poeschla EM, Hughes SH, Kvaratskhelia M, Levin HL. LEDGF/p75 interacts with mRNA splicing factors and targets HIV-1 integration to highly spliced genes. Genes Dev 2015 Nov 1;29(21):2287-2297. PubMed PMID: 26545813.
- Jurado KA, Wang H, Slaughter A, Feng L, Kessl JJ, Koh Y, Wang W, Ballandras-Colas A, Patel PA, Fuchs JR, Kvaratskhelia M, Engelman A. Allosteric integrase potency is determined through the inhibition of HIV-1 particle maturation. Proc Natl Acad Sci U S A 2013 May 21;110(21):8690-8695. PubMed PMID: 23610442.