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Molecular determinants for recognition of divergent SAMHD1 proteins by the lentiviral accessory protein Vpx.

Schwefel D, Boucherit VC, Christodoulou E, Walker PA, Stoye JP, Bishop KN, Taylor IA - Cell Host Microbe (2015)

Bottom Line: Comparison with Vpx from SIV that infects sooty mangabeys (SIVsmm) complexed with SAMHD1-DCAF1 identifies molecular determinants directing Vpx lineages to N- or C-terminal SAMHD1 sequences.Inspection of the Vpx-DCAF1 interface also reveals conservation of Vpx with the evolutionally related HIV-1/SIV accessory protein Vpr.These data suggest a unified model for how Vpx and Vpr exploit DCAF1 to promote viral replication.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Structure, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.

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Comparison to the SIVsmm Vpx/DCAF1-CtD/SAMHD1hs-CtD Structure(A) Superposition of the SIVmnd-2 Vpx/DCAF1-CtD/SAMHD1mnd-NtD and SIVsmm Vpx/DCAF1-CtD/SAMHD1hs-CtD ternary complexes. Cartoons are colored as Figure 2 with the addition of SIVsmm Vpx (orange) and SAMHD1hs-CtD (green). For clarity, only DCAF1-CtD from the mandrill complex is shown.(B and C) Quantification of reporter expression in cells stably expressing the SAMHD1mnd (1–114) degron reporter construct after transduction with increasing titers of particles expressing SIVmnd-2 Vpx with mutations in (B) the N-terminal arm (V15W) and in (C) the di-tyrosine motif (Y62A/Y65A). The level of Vpx transduction (YFP) and degron reporter (EGFP) expression was measured by flow cytometry.(D) Detailed view of the conserved VR2 Vpx di-tyrosine motif interaction with the DCAF1-CtD acidic loop and basic motifs of the SAMHD1mnd-NtD (left) and SAMHD1hs-CtD (right) degrons; see also Figure S5. Residues that contribute to the ternary interface are shown in stick representation with hydrogen bonding and salt bridge interactions displayed as dashed lines; see also Figure S6.
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fig6: Comparison to the SIVsmm Vpx/DCAF1-CtD/SAMHD1hs-CtD Structure(A) Superposition of the SIVmnd-2 Vpx/DCAF1-CtD/SAMHD1mnd-NtD and SIVsmm Vpx/DCAF1-CtD/SAMHD1hs-CtD ternary complexes. Cartoons are colored as Figure 2 with the addition of SIVsmm Vpx (orange) and SAMHD1hs-CtD (green). For clarity, only DCAF1-CtD from the mandrill complex is shown.(B and C) Quantification of reporter expression in cells stably expressing the SAMHD1mnd (1–114) degron reporter construct after transduction with increasing titers of particles expressing SIVmnd-2 Vpx with mutations in (B) the N-terminal arm (V15W) and in (C) the di-tyrosine motif (Y62A/Y65A). The level of Vpx transduction (YFP) and degron reporter (EGFP) expression was measured by flow cytometry.(D) Detailed view of the conserved VR2 Vpx di-tyrosine motif interaction with the DCAF1-CtD acidic loop and basic motifs of the SAMHD1mnd-NtD (left) and SAMHD1hs-CtD (right) degrons; see also Figure S5. Residues that contribute to the ternary interface are shown in stick representation with hydrogen bonding and salt bridge interactions displayed as dashed lines; see also Figure S6.

Mentions: Despite similar overall structure and an identical mode of DCAF1 interaction (Figure S4), the SIVmnd-2 Vpx/DCAF1 assembly recognizes the SAMHD1mnd-NtD, while the HIV-2/SIVmac/SIVsmm-type Vpx/DCAF1 are specific for the SAMHD1 C terminus. Comparison of the SIVmnd-2 system presented here with the previously determined SIVsmm/DCAF1/SAMHD1-Ctd assembly (Schwefel et al., 2014) reveals the structural determinants for these fundamentally different specificities. In both complexes, a Vpx N-terminal arm and residues at the N terminus of α1 make contacts with either the amino-terminal region in SAMHD1mnd or the CtD region of SAMHD1hs. The location of this contact on the DCAF1 disk is similar in both combined ternary interfaces (Figure 6A). However, the SAMHD1mnd N terminus makes additional contacts and occupies a larger surface area on Vpx and DCAF1, 750 Å2 and 500 Å2 versus 710 Å2 and 210 Å2 for the SAMHD1hs C terminus. In addition, in the mandrill complex, the Vpx arm folds over the first 20 residues of SAMHD1mnd trapping it against DCAF1, while the human SAMHD1 C-terminal peptide associates rather peripherally to the DCAF1/Vpx interface (Figure 6A).


Molecular determinants for recognition of divergent SAMHD1 proteins by the lentiviral accessory protein Vpx.

Schwefel D, Boucherit VC, Christodoulou E, Walker PA, Stoye JP, Bishop KN, Taylor IA - Cell Host Microbe (2015)

Comparison to the SIVsmm Vpx/DCAF1-CtD/SAMHD1hs-CtD Structure(A) Superposition of the SIVmnd-2 Vpx/DCAF1-CtD/SAMHD1mnd-NtD and SIVsmm Vpx/DCAF1-CtD/SAMHD1hs-CtD ternary complexes. Cartoons are colored as Figure 2 with the addition of SIVsmm Vpx (orange) and SAMHD1hs-CtD (green). For clarity, only DCAF1-CtD from the mandrill complex is shown.(B and C) Quantification of reporter expression in cells stably expressing the SAMHD1mnd (1–114) degron reporter construct after transduction with increasing titers of particles expressing SIVmnd-2 Vpx with mutations in (B) the N-terminal arm (V15W) and in (C) the di-tyrosine motif (Y62A/Y65A). The level of Vpx transduction (YFP) and degron reporter (EGFP) expression was measured by flow cytometry.(D) Detailed view of the conserved VR2 Vpx di-tyrosine motif interaction with the DCAF1-CtD acidic loop and basic motifs of the SAMHD1mnd-NtD (left) and SAMHD1hs-CtD (right) degrons; see also Figure S5. Residues that contribute to the ternary interface are shown in stick representation with hydrogen bonding and salt bridge interactions displayed as dashed lines; see also Figure S6.
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Related In: Results  -  Collection

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fig6: Comparison to the SIVsmm Vpx/DCAF1-CtD/SAMHD1hs-CtD Structure(A) Superposition of the SIVmnd-2 Vpx/DCAF1-CtD/SAMHD1mnd-NtD and SIVsmm Vpx/DCAF1-CtD/SAMHD1hs-CtD ternary complexes. Cartoons are colored as Figure 2 with the addition of SIVsmm Vpx (orange) and SAMHD1hs-CtD (green). For clarity, only DCAF1-CtD from the mandrill complex is shown.(B and C) Quantification of reporter expression in cells stably expressing the SAMHD1mnd (1–114) degron reporter construct after transduction with increasing titers of particles expressing SIVmnd-2 Vpx with mutations in (B) the N-terminal arm (V15W) and in (C) the di-tyrosine motif (Y62A/Y65A). The level of Vpx transduction (YFP) and degron reporter (EGFP) expression was measured by flow cytometry.(D) Detailed view of the conserved VR2 Vpx di-tyrosine motif interaction with the DCAF1-CtD acidic loop and basic motifs of the SAMHD1mnd-NtD (left) and SAMHD1hs-CtD (right) degrons; see also Figure S5. Residues that contribute to the ternary interface are shown in stick representation with hydrogen bonding and salt bridge interactions displayed as dashed lines; see also Figure S6.
Mentions: Despite similar overall structure and an identical mode of DCAF1 interaction (Figure S4), the SIVmnd-2 Vpx/DCAF1 assembly recognizes the SAMHD1mnd-NtD, while the HIV-2/SIVmac/SIVsmm-type Vpx/DCAF1 are specific for the SAMHD1 C terminus. Comparison of the SIVmnd-2 system presented here with the previously determined SIVsmm/DCAF1/SAMHD1-Ctd assembly (Schwefel et al., 2014) reveals the structural determinants for these fundamentally different specificities. In both complexes, a Vpx N-terminal arm and residues at the N terminus of α1 make contacts with either the amino-terminal region in SAMHD1mnd or the CtD region of SAMHD1hs. The location of this contact on the DCAF1 disk is similar in both combined ternary interfaces (Figure 6A). However, the SAMHD1mnd N terminus makes additional contacts and occupies a larger surface area on Vpx and DCAF1, 750 Å2 and 500 Å2 versus 710 Å2 and 210 Å2 for the SAMHD1hs C terminus. In addition, in the mandrill complex, the Vpx arm folds over the first 20 residues of SAMHD1mnd trapping it against DCAF1, while the human SAMHD1 C-terminal peptide associates rather peripherally to the DCAF1/Vpx interface (Figure 6A).

Bottom Line: Comparison with Vpx from SIV that infects sooty mangabeys (SIVsmm) complexed with SAMHD1-DCAF1 identifies molecular determinants directing Vpx lineages to N- or C-terminal SAMHD1 sequences.Inspection of the Vpx-DCAF1 interface also reveals conservation of Vpx with the evolutionally related HIV-1/SIV accessory protein Vpr.These data suggest a unified model for how Vpx and Vpr exploit DCAF1 to promote viral replication.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Structure, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.

Show MeSH
Related in: MedlinePlus