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Li H, Doray B, Jennings BC, Lee WS, Liu L, Kornfeld S, Li H. Structure of a truncated human GlcNAc-1-phosphotransferase variant reveals the basis for its hyperactivity. J Biol Chem 2024:107706. [PMID: 39178950 DOI: 10.1016/j.jbc.2024.107706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 07/30/2024] [Accepted: 08/08/2024] [Indexed: 08/26/2024] Open
Abstract
Mutations that cause loss of function of GlcNAc-1-phosphotransferase (PTase) lead to the lysosomal storage disorder mucolipidosis II. PTase is the key enzyme of the mannose 6-phosphate (M6P) targeting system that is responsible for tagging lysosomal hydrolases with the M6P moiety for their delivery to the lysosome. We had previously generated a truncated hyperactive form of PTase termed S1S3 which was shown to notably increase the phosphorylation level of secreted lysosomal enzymes and enhance their uptake by cells. Here, we report the 3.4 Å cryo-EM structure of soluble S1S3 lacking both transmembrane domains and cytosolic tails. The structure reveals a high degree of conservation of the catalytic core to full-length PTase. In this dimeric structure, the EF hand of one protomer is observed interacting with the conserved region 4 of the other. In addition, we present a high-quality EM 3D map of the UDP-GlcNAc bound form of the full-length soluble protein showing the key molecular interactions between the nucleotide sugar donor and side chain amino acids of the protein. Finally, although the domain organization of S1S3 is very similar to that of the Drosophila melanogaster (fruit fly) PTase homolog, we establish that the latter does not act on lysosomal hydrolases.
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Affiliation(s)
- Hua Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Balraj Doray
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Benjamin C Jennings
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Wang-Sik Lee
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Lin Liu
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Stuart Kornfeld
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
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Liu D, Yuan C, Guo C, Huang M, Lin D. Structural and Functional Insights into the Stealth Protein CpsY of Mycobacterium tuberculosis. Biomolecules 2023; 13:1611. [PMID: 38002293 PMCID: PMC10668966 DOI: 10.3390/biom13111611] [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: 10/16/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) is an important and harmful intracellular pathogen that is responsible for the cause of tuberculosis (TB). Mtb capsular polysaccharides can misdirect the host's immune response pathways, resulting in additional challenges in TB treatment. These capsule polysaccharides are biosynthesized by stealth proteins, including CpsY. The structure and functional mechanism of Mtb CpsY are not completely delineated. Here, we reported the crystal structure of CpsY201-520 at 1.64 Å. CpsY201-520 comprises three β-sheets with five α-helices on one side and three on the other. Four conserved regions (CR1-CR4) are located near and at the base of its catalytic cavity, and three spacer segments (S1-S3) surround the catalytic cavity. Site-directed mutagenesis demonstrated the strict conservation of R419 at CR3 and S1-S3 in regulating the phosphotransferase activity of CpsY201-520. In addition, deletion of S2 or S3 (∆S2 or ∆S3) dramatically increased the activity compared to the wild-type (WT) CpsY201-520. Results from molecular dynamics (MD) simulations showed that S2 and S3 are highly flexible. Our study provides new insights for the development of new vaccines and targeted immunotherapy against Mtb.
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Affiliation(s)
- Dafeng Liu
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; (D.L.); (C.G.)
| | - Cai Yuan
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China;
| | - Chenyun Guo
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; (D.L.); (C.G.)
| | - Mingdong Huang
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Donghai Lin
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; (D.L.); (C.G.)
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3
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Gorelik A, Illes K, Bui KH, Nagar B. Structures of the mannose-6-phosphate pathway enzyme, GlcNAc-1-phosphotransferase. Proc Natl Acad Sci U S A 2022; 119:e2203518119. [PMID: 35939698 PMCID: PMC9388126 DOI: 10.1073/pnas.2203518119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/06/2022] [Indexed: 11/18/2022] Open
Abstract
The mannose-6-phosphate (M6P) pathway is responsible for the transport of hydrolytic enzymes to lysosomes. N-acetylglucosamine-1-phosphotransferase (GNPT) catalyzes the first step of tagging these hydrolases with M6P, which when recognized by receptors in the Golgi diverts them to lysosomes. Genetic defects in the GNPT subunits, GNPTAB and GNPTG, cause the lysosomal storage diseases mucolipidosis types II and III. To better understand its function, we determined partial three-dimensional structures of the GNPT complex. The catalytic domain contains a deep cavity for binding of uridine diphosphate-N-acetylglucosamine, and the surrounding residues point to a one-step transfer mechanism. An isolated structure of the gamma subunit of GNPT reveals that it can bind to mannose-containing glycans in different configurations, suggesting that it may play a role in directing glycans into the active site. These findings may facilitate the development of therapies for lysosomal storage diseases.
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Affiliation(s)
- Alexei Gorelik
- Department of Biochemistry, McGill University, Montreal, QC H3G 0B1, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada
| | - Katalin Illes
- Department of Biochemistry, McGill University, Montreal, QC H3G 0B1, Canada
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada
| | - Bhushan Nagar
- Department of Biochemistry, McGill University, Montreal, QC H3G 0B1, Canada
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Du S, Wang G, Zhang Z, Ma C, Gao N, Xiao J. Structural insights into how GlcNAc-1-phosphotransferase directs lysosomal protein transport. J Biol Chem 2022; 298:101702. [PMID: 35148990 PMCID: PMC8913297 DOI: 10.1016/j.jbc.2022.101702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 11/28/2022] Open
Abstract
GlcNAc-1-phosphotransferase catalyzes the initial step in the formation of the mannose-6-phosphate tag that labels ∼60 lysosomal proteins for transport. Mutations in GlcNAc-1-phosphotransferase are known to cause lysosomal storage disorders such as mucolipidoses. However, the molecular mechanism of GlcNAc-1-phosphotransferase activity remains unclear. Mammalian GlcNAc-1-phosphotransferases are α2β2γ2 hexamers in which the core catalytic α- and β-subunits are derived from the GNPTAB (N-acetylglucosamine-1-phosphate transferase subunits alpha and beta) gene. Here, we present the cryo-electron microscopy structure of the Drosophila melanogaster GNPTAB homolog, DmGNPTAB. We identified four conserved regions located far apart in the sequence that fold into the catalytic domain, which exhibits structural similarity to that of the UDP–glucose glycoprotein glucosyltransferase. Comparison with UDP–glucose glycoprotein glucosyltransferase also revealed a putative donor substrate-binding site, and the functional requirements of critical residues in human GNPTAB were validated using GNPTAB-knockout cells. Finally, we show that DmGNPTAB forms a homodimer that is evolutionarily conserved and that perturbing the dimer interface undermines the maturation and activity of human GNPTAB. These results provide important insights into GlcNAc-1-phosphotransferase function and related diseases.
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Affiliation(s)
- Shuo Du
- State Key Laboratory of Protein and Plant Gene Research, Peking University, Beijing 100871, China; School of Life Sciences, Peking University, Beijing 100871, China
| | - Guopeng Wang
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Zhiying Zhang
- State Key Laboratory of Protein and Plant Gene Research, Peking University, Beijing 100871, China; School of Life Sciences, Peking University, Beijing 100871, China
| | - Chengying Ma
- School of Life Sciences, Peking University, Beijing 100871, China; State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Ning Gao
- School of Life Sciences, Peking University, Beijing 100871, China; State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
| | - Junyu Xiao
- State Key Laboratory of Protein and Plant Gene Research, Peking University, Beijing 100871, China; School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Beijing Advanced Innovation Center for Genomics, Peking University, Beijing 100871, China.
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Matos L, Vilela R, Rocha M, Santos JI, Coutinho MF, Gaspar P, Prata MJ, Alves S. Development of an Antisense Oligonucleotide-Mediated Exon Skipping Therapeutic Strategy for Mucolipidosis II: Validation at RNA Level. Hum Gene Ther 2020; 31:775-783. [PMID: 32283951 DOI: 10.1089/hum.2020.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lysosomal storage disorders (LSDs) are a group of rare inherited metabolic diseases caused by the malfunction of the lysosomal system, which results in the accumulation of undergraded substrates inside the lysosomes and leads to severe and progressive pathology. Despite there currently being a broad understanding of the molecular defects behind LSDs, curative therapies have been approved for only few of these diseases, whereas existing treatments are still mostly symptomatic with several limitations. Mucolipidosis type II alpha/beta (ML II) is one of most severe LSDs, which is caused by the total deficiency of the GlcNAc-1-phosphotransferase, a key enzyme for the formation of specific targeting signals on lysosomal hydrolases to lysosomes. GlcNAc-1-phosphotransferase is a multimeric enzyme complex encoded by two genes: GNPTAB and GNPTG. One of the most frequent ML II causal mutation is a dinucleotide deletion on exon 19 of GNPTAB (c.3503_3504del) that leads to the generation of a truncated protein, loss of GlcNAc-1-phosphotransferase activity, and missorting of multiple lysosomal enzymes. Presently, there is no therapy available for ML II. In this study, we explored the possibility of an innovative therapeutic strategy for ML II based on the use of antisense oligonucleotides (AOs) capable to induce the skipping of GNPTAB exon 19 harboring the most common disease-causing mutation, c.3503_3504del. The approach confirmed the ability of specific AOs for RNA splicing modulation, thus paving the way for future studies on the therapeutic potential of this strategy.
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Affiliation(s)
- Liliana Matos
- Research and Development Unit, Department of Human Genetics, National Health Institute Doutor Ricardo Jorge, Porto, Portugal.,Center for the Study of Animal Science, CECA-ICETA, University of Porto, Porto, Portugal
| | - Regina Vilela
- Research and Development Unit, Department of Human Genetics, National Health Institute Doutor Ricardo Jorge, Porto, Portugal
| | - Melissa Rocha
- Research and Development Unit, Department of Human Genetics, National Health Institute Doutor Ricardo Jorge, Porto, Portugal
| | - Juliana I Santos
- Research and Development Unit, Department of Human Genetics, National Health Institute Doutor Ricardo Jorge, Porto, Portugal.,Biology Department, Faculty of Sciences, University of Porto, Porto, Portugal
| | - Maria Francisca Coutinho
- Research and Development Unit, Department of Human Genetics, National Health Institute Doutor Ricardo Jorge, Porto, Portugal.,Center for the Study of Animal Science, CECA-ICETA, University of Porto, Porto, Portugal
| | - Paulo Gaspar
- Newborn Screening, Metabolism and Genetics Unit, Department of Human Genetics, National Health Institute Doutor Ricardo Jorge, Porto, Portugal
| | - Maria João Prata
- Biology Department, Faculty of Sciences, University of Porto, Porto, Portugal.,i3S, Institute of Research and Innovation in Health/IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
| | - Sandra Alves
- Research and Development Unit, Department of Human Genetics, National Health Institute Doutor Ricardo Jorge, Porto, Portugal.,Center for the Study of Animal Science, CECA-ICETA, University of Porto, Porto, Portugal
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