1
|
Hu Y, Gudnadóttir RB, Knecht KM, Arizaga F, Jónsson SR, Xiong Y. Structural basis for recruitment of host CypA and E3 ubiquitin ligase by maedi-visna virus Vif. Sci Adv 2023; 9:eadd3422. [PMID: 36638173 PMCID: PMC9839330 DOI: 10.1126/sciadv.add3422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Lentiviral Vif molecules target the host antiviral APOBEC3 proteins for destruction in cellular ubiquitin-proteasome pathways. Different lentiviral Vifs have evolved to use the same canonical E3 ubiquitin ligase complexes, along with distinct noncanonical host cofactors for their activities. Unlike primate lentiviral Vif, which recruits CBFβ as the noncanonical cofactor, nonprimate lentiviral Vif proteins have developed different cofactor recruitment mechanisms. Maedi-visna virus (MVV) sequesters CypA as the noncanonical cofactor for the Vif-mediated ubiquitination of ovine APOBEC3s. Here, we report the cryo-electron microscopy structure of MVV Vif in complex with CypA and E3 ligase components. The structure, along with our biochemical and functional analysis, reveals both conserved and unique structural elements of MVV Vif and its common and distinct interaction modes with various cognate cellular proteins, providing a further understanding of the evolutionary relationship between lentiviral Vifs and the molecular mechanisms by which they capture different host cofactors for immune evasion activities.
Collapse
Affiliation(s)
- Yingxia Hu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Ragna B. Gudnadóttir
- Institute for Experimental Pathology, University of Iceland, Keldur, Reykjavik 112, Iceland
| | - Kirsten M. Knecht
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Fidel Arizaga
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Stefán R. Jónsson
- Institute for Experimental Pathology, University of Iceland, Keldur, Reykjavik 112, Iceland
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| |
Collapse
|
2
|
Bowen NE, Temple J, Shepard C, Oo A, Arizaga F, Kapoor-Vazirani P, Persaud M, Yu CH, Kim DH, Schinazi RF, Ivanov DN, Diaz-Griffero F, Yu DS, Xiong Y, Kim B. Structural and functional characterization explains loss of dNTPase activity of the cancer-specific R366C/H mutant SAMHD1 proteins. J Biol Chem 2021; 297:101170. [PMID: 34492268 PMCID: PMC8497992 DOI: 10.1016/j.jbc.2021.101170] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 01/09/2023] Open
Abstract
Elevated intracellular levels of dNTPs have been shown to be a biochemical marker of cancer cells. Recently, a series of mutations in the multifunctional dNTP triphosphohydrolase (dNTPase), sterile alpha motif and histidine-aspartate domain-containing protein 1 (SAMHD1), have been reported in various cancers. Here, we investigated the structure and functions of SAMHD1 R366C/H mutants, found in colon cancer and leukemia. Unlike many other cancer-specific mutations, the SAMHD1 R366 mutations do not alter cellular protein levels of the enzyme. However, R366C/H mutant proteins exhibit a loss of dNTPase activity, and their X-ray structures demonstrate the absence of dGTP substrate in their active site, likely because of a loss of interaction with the γ-phosphate of the substrate. The R366C/H mutants failed to reduce intracellular dNTP levels and restrict HIV-1 replication, functions of SAMHD1 that are dependent on the ability of the enzyme to hydrolyze dNTPs. However, these mutants retain dNTPase-independent functions, including mediating dsDNA break repair, interacting with CtIP and cyclin A2, and suppressing innate immune responses. Finally, SAMHD1 degradation in human primary-activated/dividing CD4+ T cells further elevates cellular dNTP levels. This study suggests that the loss of SAMHD1 dNTPase activity induced by R366 mutations can mechanistically contribute to the elevated dNTP levels commonly found in cancer cells.
Collapse
Affiliation(s)
- Nicole E Bowen
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Joshua Temple
- Department of Molecular Biophysics and Biochemistry, School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Caitlin Shepard
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Adrian Oo
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Fidel Arizaga
- Department of Molecular Biophysics and Biochemistry, School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Priya Kapoor-Vazirani
- Department of Radiation Oncology, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Mirjana Persaud
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Corey H Yu
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Dong-Hyun Kim
- School of Pharmacy, Kyung-Hee University, Seoul, South Korea
| | - Raymond F Schinazi
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Dmitri N Ivanov
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Felipe Diaz-Griffero
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - David S Yu
- Department of Radiation Oncology, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, School of Medicine, Yale University, New Haven, Connecticut, USA.
| | - Baek Kim
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, Georgia, USA; Children's Healthcare of Atlanta, Atlanta, Georgia, USA.
| |
Collapse
|