Molecular determinants for recognition of divergent SAMHD1 proteins by the lentiviral accessory protein Vpx
journal contributionposted on 09.09.2020, 13:53 by David Schwefel, Virginie C Boucherit, Evangelos Christodoulou, Philip A Walker, Jonathan P Stoye, Kate N Bishop, Ian A Taylor
The SAMHD1 triphosphohydrolase inhibits HIV-1 infection of myeloid and resting T cells by depleting dNTPs. To overcome SAMHD1, HIV-2 and some SIVs encode either of two lineages of the accessory protein Vpx that bind the SAMHD1 N or C terminus and redirect the host cullin-4 ubiquitin ligase to target SAMHD1 for proteasomal degradation. We present the ternary complex of Vpx from SIV that infects mandrills (SIVmnd-2) with the cullin-4 substrate receptor, DCAF1, and N-terminal and SAM domains from mandrill SAMHD1. The structure reveals details of Vpx lineage-specific targeting of SAMHD1 N-terminal "degron" sequences. 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.
AnimalsCarrier ProteinsCrystallography, X-RayHost-Pathogen InteractionsMandrillusModels, MolecularMonomeric GTP-Binding ProteinsProtein ConformationProtein MultimerizationViral Regulatory and Accessory ProteinsVirus ReplicationBishop U117592729Stoye U117512710Taylor, I U117565647SBImmunology0605 Microbiology1108 Medical Microbiology