Noncovalent SUMO-interaction motifs in HIV integrase play important roles in SUMOylation, cofactor binding, and virus replication

Abstract

Background HIV integrase (IN) and its cellular cofactors, including lens-epithelium-derived growth factor (LEDGF/p75), Ku70, p300, and Rad52, are subject to small ubiquitin-like modifier (SUMO) modification. In addition to covalent SUMOylation, SUMO paralogs can also noncovalently bind proteins through SUMO-interacting motifs (SIMs). However, little is known about whether HIV IN contains SIMs and the roles of these motifs. Results We searched for the amino acid sequence of HIV IN and investigated three putative SIMs of IN: SIM1 72VILV75, SIM2 200IVDI203 and SIM3 257IKVV260. Our mutational analysis showed that 200IVDI203 and 257IKVV260 are two bona fide SIMs that mediate IN-SUMO noncovalent interactions. Additionally, a cell-based SUMOylation assay revealed that IN SIMs negatively regulate the SUMOylation of IN, as well as the interaction between IN and SUMO E2 conjugation enzyme Ubc9. Conversely, IN SIMs are required for its interactions with LEDGF/p75 but not with Ku70. Furthermore, our study reveals that SIM2 and SIM3 are required for the nuclear localization of IN. Finally, we investigated the impact of IN SIM2 and SIM3 on HIV single cycle replication in CD4 + C8166 T cells, and the results showed that viruses carrying IN SIM mutants are replication defective at the steps of the early viral life cycle, including reverse transcription, nuclear import and integration. Conclusion Our data suggested that the IN SIM -SUMO interaction constitutes a new regulatory mechanism of IN functions and might be important for HIV-1 replication.

NS5 Sumoylation Directs Nuclear Responses That Permit Zika Virus To Persistently Infect Human Brain Microvascular Endothelial Cells

“…SUMO-1 and other posttranslational modifiers regulate protein-protein interactions that form NBs, control their composition structurally and functionally, and are associated with nuclear pore complexes and HDAC1 transcriptional repression (18). Mutating SIM sites in viral proteins has also been shown to inhibit SUMOylation, impair complex formation, and change NB cellular localization (52,53). SUMOylation also coordinates the repression of tightly controlled basal and IFN-induced ISG responses that direct cellular antiviral programs (48).…”

First report of computational protein–ligand docking to evaluate susceptibility to HIV integrase inhibitors in HIV-infected Iranian patients

“…INT undergoes multiple PMTs that play versatile roles in the functions of INT and HIV-1 viral replication [ 87 ]. Phosphorylation prediction suggested some residues appropriate for phosphorylation that may be required for the interaction of INT with cellular factors that either tether or stimulate the integration into the genome.…”

“…INT is susceptible to be SUMOylated at three SUMOylation sites (45LKGE, 135IKQE, and 243WKQE) on three Lys residues (K46, K136, and K244). INT SUMOylation impairment correlated with a significant drop in integration events and inhibited replication [ 87 , 90 , 91 ].…”

The C-Terminal Domain of HIV-1 Integrase: A Swiss Army Knife for the Virus?

“…During infection, HIV-1 IN undergoes various post-translational modifications (PTMs), which tightly regulate its enzymatic function and its interaction with numerous cellular cofactors [ 47 , 48 , 49 , 50 , 51 , 52 ]. These modifications are mainly acetylation, ubiquitination, SUMOylation and phosphorylation and mostly occur in the C-terminal region of the protein (reviewed in [ 52 ]; Figure 6 ).…”