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Sukla S, Dhakshinamoorthy DR, Ramesh AV, Lew S, Su M, Seetharaman J. Crystal structure of human Cep57 C-terminal domain reveals the presence of leucine zipper and the potential microtubule binding region. Proteins 2024; 92:1137-1143. [PMID: 38699879 DOI: 10.1002/prot.26698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/04/2024] [Accepted: 04/22/2024] [Indexed: 05/05/2024]
Abstract
Cep57, a vital centrosome-associated protein, recruits essential regulatory enzymes for centriole duplication. Its dysfunction leads to anomalies, including reduced centrioles and mosaic-variegated aneuploidy syndrome. Despite functional investigations, understanding structural aspects and their correlation with functions is partial till date. We present the structure of human Cep57 C-terminal microtubule binding (MT-BD) domain, revealing conserved motifs ensuring functional preservation across evolution. A leucine zipper, with an adjacent possible microtubule-binding region, potentially forms a stabilizing scaffold for microtubule nucleation-accommodating pulling and tension from growing microtubules. This study highlights conserved structural features of Cep57 protein, compares them with other analogous proteins, and explores how protein function is maintained across diverse organisms.
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Affiliation(s)
- Sanskrita Sukla
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | | | - Arvind V Ramesh
- Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Scott Lew
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Min Su
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Jayaraman Seetharaman
- Department of Pharmacology, Addiction Science, and Toxicology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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Murata T. Tegument proteins of Epstein-Barr virus: Diverse functions, complex networks, and oncogenesis. Tumour Virus Res 2023; 15:200260. [PMID: 37169175 DOI: 10.1016/j.tvr.2023.200260] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/13/2023] Open
Abstract
The tegument is the structure between the envelope and nucleocapsid of herpesvirus particles. Viral (and cellular) proteins accumulate to create the layers of the tegument. Some Epstein-Barr virus (EBV) tegument proteins are conserved widely in Herpesviridae, but others are shared only by members of the gamma-herpesvirus subfamily. As the interface to envelope and nucleocapsid, the tegument functions in virion morphogenesis and budding of the nucleocapsid during progeny production. When a virus particle enters a cell, enzymes such as kinase and deubiquitinase, and transcriptional activators are released from the virion to promote virus infection. Moreover, some EBV tegument proteins are involved in oncogenesis. Here, we summarize the roles of EBV tegument proteins, in comparison to those of other herpesviruses.
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Affiliation(s)
- Takayuki Murata
- Department of Virology, Fujita Health University School of Medicine, Toyoake, Japan.
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Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) inhibitor of cyclic GMP-AMP synthase (cGAS) (KicGAS) encoded by ORF52 is a conserved major tegument protein of KSHV and the first reported viral inhibitor of cGAS. In our previous study, we found that KicGAS is highly oligomerized in solution and that oligomerization is required for its cooperative DNA binding and for inhibiting DNA-induced phase separation and activation of cGAS. However, how KicGAS oligomerizes remained unclear. Here, we present the crystal structure of KicGAS at 2.5 Å resolution, which reveals an "L"-shaped molecule with each arm of the L essentially formed by a single α helix (α1 and α2). Antiparallel dimerization of α2 helices from two KicGAS molecules leads to a unique "Z"-shaped dimer. Surprisingly, α1 is also a dimerization domain. It forms a parallel dimeric leucine zipper with the α1 from a neighboring dimer, leading to the formation of an infinite chain of KicGAS dimers. Residues involved in leucine zipper dimer formation are among the most conserved residues across ORF52 homologs of gammaherpesviruses. The self-oligomerization increases the valence and cooperativity of interaction with DNA. The resultant multivalent interaction is critical for the formation of liquid condensates with DNA and consequent sequestration of DNA from being sensed by cGAS, explaining its role in restricting cGAS activation. The structure presented here not only provides a mechanistic understanding of the function of KicGAS but also informs a molecular target for rational design of antivirals against KSHV and related viruses.
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O'Grady T, Feswick A, Hoffman BA, Wang Y, Medina EM, Kara M, van Dyk LF, Flemington EK, Tibbetts SA. Genome-wide Transcript Structure Resolution Reveals Abundant Alternate Isoform Usage from Murine Gammaherpesvirus 68. Cell Rep 2019; 27:3988-4002.e5. [PMID: 31242428 PMCID: PMC7071827 DOI: 10.1016/j.celrep.2019.05.086] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 02/27/2019] [Accepted: 05/22/2019] [Indexed: 12/18/2022] Open
Abstract
The gammaherpesviruses, including Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), and murine gammaherpesvirus 68 (MHV68, MuHV-4, γHV68), are etiologic agents of a wide range of lymphomas and non-hematological malignancies. These viruses possess large and highly dense dsDNA genomes that feature >80 bidirectionally positioned open reading frames (ORFs). The abundance of overlapping transcripts and extensive splicing throughout these genomes have until now prohibited high throughput-based resolution of transcript structures. Here, we integrate the capabilities of long-read sequencing with the accuracy of short-read platforms to globally resolve MHV68 transcript structures using the transcript resolution through integration of multi-platform data (TRIMD) pipeline. This approach reveals highly complex features, including: (1) pervasive overlapping transcript structures; (2) transcripts containing intra-gene or trans-gene splices that yield chimeric ORFs; (3) antisense and intergenic transcripts containing ORFs; and (4) noncoding transcripts. This work sheds light on the underappreciated complexity of gammaherpesvirus transcription and provides an extensively revised annotation of the MHV68 transcriptome.
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Affiliation(s)
- Tina O'Grady
- Laboratory of Gene Expression and Cancer, GIGA-R (MBD), University of Liège, Liège, Belgium
| | - April Feswick
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Brett A Hoffman
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Yiping Wang
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Eva M Medina
- Department of Immunology and Microbiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Mehmet Kara
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Linda F van Dyk
- Department of Immunology and Microbiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Erik K Flemington
- Department of Pathology, Tulane Cancer Center, Tulane University, New Orleans, LA, USA.
| | - Scott A Tibbetts
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA.
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