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Osher E, Anis Y, Singer-Shapiro R, Urshanski N, Unger T, Albeck S, Bogin O, Weisinger G, Kohen F, Valevski A, Fattal-Valevski A, Sagi L, Weitman M, Shenberger Y, Sagiv N, Navon R, Wilchek M, Stern N. Treating late-onset Tay Sachs disease: Brain delivery with a dual trojan horse protein. Mol Ther Methods Clin Dev 2024; 32:101300. [PMID: 39211733 PMCID: PMC11357852 DOI: 10.1016/j.omtm.2024.101300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 07/13/2024] [Indexed: 09/04/2024]
Abstract
Tay-Sachs (TS) disease is a neurodegenerative disease resulting from mutations in the gene encoding the α-subunit (HEXA) of lysosomal β-hexosaminidase A (HexA). We report that (1) recombinant HEXA alone increased HexA activity and decreased GM2 content in human TS glial cells and peripheral mononuclear blood cells; 2) a recombinant chimeric protein composed of HEXA linked to two blood-brain barrier (BBB) entry elements, a transferrin receptor binding sequence and granulocyte-colony stimulating factor, associates with HEXB in vitro; reaches human cultured TS cells lysosomes and mouse brain cells, especially neurons, in vivo; lowers GM2 in cultured human TS cells; lowers whole brain GM2 concentration by approximately 40% within 6 weeks, when injected intravenously (IV) to adult TS-mutant mice mimicking the slow course of late-onset TS; and increases forelimbs grip strength. Hence, a chimeric protein equipped with dual BBB entry elements can transport a large protein such as HEXA to the brain, decrease the accumulation of GM2, and improve muscle strength, thereby providing potential treatment for late-onset TS.
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Affiliation(s)
- Esther Osher
- The Sagol Center for Epigenetics and Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yossi Anis
- The Sagol Center for Epigenetics and Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
| | - Ruth Singer-Shapiro
- The Sagol Center for Epigenetics and Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
| | - Nataly Urshanski
- The Sagol Center for Epigenetics and Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
| | - Tamar Unger
- Department of Structural Proteomics, Weizmann Institute of Science, Rehovot, Israel
| | - Shira Albeck
- Department of Structural Proteomics, Weizmann Institute of Science, Rehovot, Israel
| | - Oren Bogin
- The Sagol Center for Epigenetics and Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
| | - Gary Weisinger
- The Sagol Center for Epigenetics and Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
| | - Fortune Kohen
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot, Israel
| | | | | | - Liora Sagi
- Pediatric Neurology Unit, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
| | - Michal Weitman
- The Chemistry Department, Bar Ian University, Ramat Gan, Israel
| | | | - Nadav Sagiv
- The Sagol Center for Epigenetics and Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
| | - Ruth Navon
- Department of Human Molecular Genetics & Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Meir Wilchek
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Naftali Stern
- The Sagol Center for Epigenetics and Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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Alvarado-Fernández AM, Rodríguez-López EA, Espejo-Mojica AJ, Mosquera-Arévalo AR, Alméciga-Díaz CJ, Trespalacios-Rangel AA. Effect of two preservation methods on the viability and enzyme production of a recombinant Komagataella phaffii (Pichia pastoris) strain. Cryobiology 2021; 105:32-40. [PMID: 34951975 DOI: 10.1016/j.cryobiol.2021.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 12/16/2021] [Accepted: 12/18/2021] [Indexed: 11/18/2022]
Abstract
The methylotrophic yeast Komagataella phaffii, previously known as Pichia pastoris, has been reported as a host for producing human recombinant lysosomal enzymes intended for enzyme replacement therapy. K. phaffii has advantages such as easy genetic handling, rapid growth, cost-effective mediums, and the ability to develop mammalian-like post-translational modifications. To maintain cell viability and enzyme activity over time, it is important to consider the bioprocess optimization and the proper selection and preservation of clones. In this study, we evaluated the effect of glycerol and skim milk in cryopreservation at -80 °C, as well as the use of skim milk or its combination with NaCl, disaccharides or sorbitol in freeze-drying on the cell viability and activity of a recombinant lysosomal enzyme (i.e., human β-hexosaminidase-A) produced in K. phaffii GS115 strain. The results showed that cryopreservation with glycerol and skim milk, as well as freeze-drying using disaccharides and sorbitol with skim milk, maintained the viability above 80%. Although variations in enzyme activity among treatments were found, the use of disaccharides had a positive effect on the enzymatic activity levels. This is the first report of the evaluation of two suitable methods to preserve a recombinant K. phaffii strain, preventing the loss of viability and maintaining the activity of the recombinant protein.
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Affiliation(s)
| | - Edwin Alexander Rodríguez-López
- Institute for the Study of Inborn Errors of Metabolism. Faculty of Sciences. Pontificia Universidad Javeriana. Bogotá D.C., Colombia; Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC). Bogotá D.C., Colombia.
| | - Angela Johana Espejo-Mojica
- Institute for the Study of Inborn Errors of Metabolism. Faculty of Sciences. Pontificia Universidad Javeriana. Bogotá D.C., Colombia.
| | | | - Carlos Javier Alméciga-Díaz
- Institute for the Study of Inborn Errors of Metabolism. Faculty of Sciences. Pontificia Universidad Javeriana. Bogotá D.C., Colombia.
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3
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Leal AF, Benincore-Flórez E, Solano-Galarza D, Garzón Jaramillo RG, Echeverri-Peña OY, Suarez DA, Alméciga-Díaz CJ, Espejo-Mojica AJ. GM2 Gangliosidoses: Clinical Features, Pathophysiological Aspects, and Current Therapies. Int J Mol Sci 2020; 21:ijms21176213. [PMID: 32867370 PMCID: PMC7503724 DOI: 10.3390/ijms21176213] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/03/2020] [Accepted: 08/07/2020] [Indexed: 12/16/2022] Open
Abstract
GM2 gangliosidoses are a group of pathologies characterized by GM2 ganglioside accumulation into the lysosome due to mutations on the genes encoding for the β-hexosaminidases subunits or the GM2 activator protein. Three GM2 gangliosidoses have been described: Tay-Sachs disease, Sandhoff disease, and the AB variant. Central nervous system dysfunction is the main characteristic of GM2 gangliosidoses patients that include neurodevelopment alterations, neuroinflammation, and neuronal apoptosis. Currently, there is not approved therapy for GM2 gangliosidoses, but different therapeutic strategies have been studied including hematopoietic stem cell transplantation, enzyme replacement therapy, substrate reduction therapy, pharmacological chaperones, and gene therapy. The blood-brain barrier represents a challenge for the development of therapeutic agents for these disorders. In this sense, alternative routes of administration (e.g., intrathecal or intracerebroventricular) have been evaluated, as well as the design of fusion peptides that allow the protein transport from the brain capillaries to the central nervous system. In this review, we outline the current knowledge about clinical and physiopathological findings of GM2 gangliosidoses, as well as the ongoing proposals to overcome some limitations of the traditional alternatives by using novel strategies such as molecular Trojan horses or advanced tools of genome editing.
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Affiliation(s)
- Andrés Felipe Leal
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; (A.F.L.); (E.B.-F); (D.S.-G.); (R.G.G.J.); (O.Y.E.-P.); (D.A.S.)
| | - Eliana Benincore-Flórez
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; (A.F.L.); (E.B.-F); (D.S.-G.); (R.G.G.J.); (O.Y.E.-P.); (D.A.S.)
| | - Daniela Solano-Galarza
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; (A.F.L.); (E.B.-F); (D.S.-G.); (R.G.G.J.); (O.Y.E.-P.); (D.A.S.)
| | - Rafael Guillermo Garzón Jaramillo
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; (A.F.L.); (E.B.-F); (D.S.-G.); (R.G.G.J.); (O.Y.E.-P.); (D.A.S.)
| | - Olga Yaneth Echeverri-Peña
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; (A.F.L.); (E.B.-F); (D.S.-G.); (R.G.G.J.); (O.Y.E.-P.); (D.A.S.)
| | - Diego A. Suarez
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; (A.F.L.); (E.B.-F); (D.S.-G.); (R.G.G.J.); (O.Y.E.-P.); (D.A.S.)
- Faculty of Medicine, Universidad Nacional de Colombia, Bogotá 110231, Colombia
| | - Carlos Javier Alméciga-Díaz
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; (A.F.L.); (E.B.-F); (D.S.-G.); (R.G.G.J.); (O.Y.E.-P.); (D.A.S.)
- Correspondence: (C.J.A.-D.); (A.J.E.-M.); Tel.: +57-1-3208320 (ext. 4140) (C.J.A.-D.); +57-1-3208320 (ext. 4099) (A.J.E.-M.)
| | - Angela Johana Espejo-Mojica
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; (A.F.L.); (E.B.-F); (D.S.-G.); (R.G.G.J.); (O.Y.E.-P.); (D.A.S.)
- Correspondence: (C.J.A.-D.); (A.J.E.-M.); Tel.: +57-1-3208320 (ext. 4140) (C.J.A.-D.); +57-1-3208320 (ext. 4099) (A.J.E.-M.)
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4
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In silico analysis of the effects of disease-associated mutations of β-hexosaminidase A in Tay‒Sachs disease. J Genet 2020. [DOI: 10.1007/s12041-020-01208-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Dersh D, Iwamoto Y, Argon Y. Tay-Sachs disease mutations in HEXA target the α chain of hexosaminidase A to endoplasmic reticulum-associated degradation. Mol Biol Cell 2016; 27:3813-3827. [PMID: 27682588 PMCID: PMC5170605 DOI: 10.1091/mbc.e16-01-0012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 09/15/2016] [Accepted: 09/22/2016] [Indexed: 12/29/2022] Open
Abstract
In Tay–Sachs disease, mutations in HEXA can lead to aberrant α subunits of the HexA enzyme. Two such mutants have folding defects and are cleared by endoplasmic reticulum-associated degradation. Toward the pursuit of therapeutic treatments, it was found that manipulating endoplasmic reticulum quality control can impair mutant α degradation and improve cellular Hex activity. Loss of function of the enzyme β-hexosaminidase A (HexA) causes the lysosomal storage disorder Tay–Sachs disease (TSD). It has been proposed that mutations in the α chain of HexA can impair folding, enzyme assembly, and/or trafficking, yet there is surprisingly little known about the mechanisms of these potential routes of pathogenesis. We therefore investigated the biosynthesis and trafficking of TSD-associated HexA α mutants, seeking to identify relevant cellular quality control mechanisms. The α mutants E482K and G269S are defective in enzymatic activity, unprocessed by lysosomal proteases, and exhibit altered folding pathways compared with wild-type α. E482K is more severely misfolded than G269S, as observed by its aggregation and inability to associate with the HexA β chain. Importantly, both mutants are retrotranslocated from the endoplasmic reticulum (ER) to the cytosol and are degraded by the proteasome, indicating that they are cleared via ER-associated degradation (ERAD). Leveraging these discoveries, we observed that manipulating the cellular folding environment or ERAD pathways can alter the kinetics of mutant α degradation. Additionally, growth of patient fibroblasts at a permissive temperature or with chemical chaperones increases cellular Hex activity by improving mutant α folding. Therefore modulation of the ER quality control systems may be a potential therapeutic route for improving some forms of TSD.
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Affiliation(s)
- Devin Dersh
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104
| | - Yuichiro Iwamoto
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104
| | - Yair Argon
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104
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6
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Fan X, Tkachyova I, Sinha A, Rigat B, Mahuran D. Characterization of the biosynthesis, processing and kinetic mechanism of action of the enzyme deficient in mucopolysaccharidosis IIIC. PLoS One 2011; 6:e24951. [PMID: 21957468 PMCID: PMC3177862 DOI: 10.1371/journal.pone.0024951] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 08/22/2011] [Indexed: 11/18/2022] Open
Abstract
Heparin acetyl-CoA:alpha-glucosaminide N-acetyltransferase (N-acetyltransferase, EC 2.3.1.78) is an integral lysosomal membrane protein containing 11 transmembrane domains, encoded by the HGSNAT gene. Deficiencies of N-acetyltransferase lead to mucopolysaccharidosis IIIC. We demonstrate that contrary to a previous report, the N-acetyltransferase signal peptide is co-translationally cleaved and that this event is required for its intracellular transport to the lysosome. While we confirm that the N-acetyltransferase precursor polypeptide is processed in the lysosome into a small amino-terminal alpha- and a larger ß- chain, we further characterize this event by identifying the mature amino-terminus of each chain. We also demonstrate this processing step(s) is not, as previously reported, needed to produce a functional transferase, i.e., the precursor is active. We next optimize the biochemical assay procedure so that it remains linear as N-acetyltransferase is purified or protein-extracts containing N-acetyltransferase are diluted, by the inclusion of negatively charged lipids. We then use this assay to demonstrate that the purified single N-acetyltransferase protein is both necessary and sufficient to express transferase activity, and that N-acetyltransferase functions as a monomer. Finally, the kinetic mechanism of action of purified N-acetyltransferase was evaluated and found to be a random sequential mechanism involving the formation of a ternary complex with its two substrates; i.e., N-acetyltransferase does not operate through a ping-pong mechanism as previously reported. We confirm this conclusion by demonstrating experimentally that no acetylated enzyme intermediate is formed during the reaction.
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Affiliation(s)
- Xiaolian Fan
- Genetics and Genome Biology Program, The Hospital For Sick Children, Toronto, Canada
| | - Ilona Tkachyova
- Genetics and Genome Biology Program, The Hospital For Sick Children, Toronto, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Ankit Sinha
- Genetics and Genome Biology Program, The Hospital For Sick Children, Toronto, Canada
| | - Brigitte Rigat
- Genetics and Genome Biology Program, The Hospital For Sick Children, Toronto, Canada
| | - Don Mahuran
- Genetics and Genome Biology Program, The Hospital For Sick Children, Toronto, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
- * E-mail:
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7
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Akeboshi H, Chiba Y, Kasahara Y, Takashiba M, Takaoka Y, Ohsawa M, Tajima Y, Kawashima I, Tsuji D, Itoh K, Sakuraba H, Jigami Y. Production of recombinant beta-hexosaminidase A, a potential enzyme for replacement therapy for Tay-Sachs and Sandhoff diseases, in the methylotrophic yeast Ogataea minuta. Appl Environ Microbiol 2007; 73:4805-12. [PMID: 17557860 PMCID: PMC1951009 DOI: 10.1128/aem.00463-07] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Accepted: 05/24/2007] [Indexed: 01/28/2023] Open
Abstract
Human beta-hexosaminidase A (HexA) is a heterodimeric glycoprotein composed of alpha- and beta-subunits that degrades GM2 gangliosides in lysosomes. GM2 gangliosidosis is a lysosomal storage disease in which an inherited deficiency of HexA causes the accumulation of GM2 gangliosides. In order to prepare a large amount of HexA for a treatment based on enzyme replacement therapy (ERT), recombinant HexA was produced in the methylotrophic yeast Ogataea minuta instead of in mammalian cells, which are commonly used to produce recombinant enzymes for ERT. The problem of antigenicity due to differences in N-glycan structures between mammalian and yeast glycoproteins was potentially resolved by using alpha-1,6-mannosyltransferase-deficient (och1Delta) yeast as the host. Genes encoding the alpha- and beta-subunits of HexA were integrated into the yeast cell, and the heterodimer was expressed together with its isozymes HexS (alphaalpha) and HexB (betabeta). A total of 57 mg of beta-hexosaminidase isozymes, of which 13 mg was HexA (alphabeta), was produced per liter of medium. HexA was purified with immobilized metal affinity column for the His tag attached to the beta-subunit. The purified HexA was treated with alpha-mannosidase to expose mannose-6-phosphate (M6P) residues on the N-glycans. The specific activities of HexA and M6P-exposed HexA (M6PHexA) for the artificial substrate 4MU-GlcNAc were 1.2 +/- 0.1 and 1.7 +/- 0.3 mmol/h/mg, respectively. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern suggested a C-terminal truncation in the beta-subunit of the recombinant protein. M6PHexA was incorporated dose dependently into GM2 gangliosidosis patient-derived fibroblasts via M6P receptors on the cell surface, and degradation of accumulated GM2 ganglioside was observed.
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Affiliation(s)
- Hiromi Akeboshi
- Research Center for Glycoscience, AIST Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki, Japan
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8
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Tomiya N, Narang S, Park J, Abdul-Rahman B, Choi O, Singh S, Hiratake J, Sakata K, Betenbaugh MJ, Palter KB, Lee YC. Purification, Characterization, and Cloning of a Spodoptera frugiperda Sf9 β-N-Acetylhexosaminidase That Hydrolyzes Terminal N-Acetylglucosamine on the N-Glycan Core. J Biol Chem 2006; 281:19545-60. [PMID: 16684772 DOI: 10.1074/jbc.m603312200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Paucimannosidic glycans are often predominant in N-glycans produced by insect cells. However, a beta-N-acetylhexosaminidase responsible for the generation of paucimannosidic glycans in lepidopteran insect cells has not been identified. We report the purification of a beta-N-acetylhexosaminidase from the culture medium of Spodoptera frugiperda Sf9 cells (Sfhex). The purified Sfhex protein showed 10 times higher activity for a terminal N-acetylglucosamine on the N-glycan core compared with tri-N-acetylchitotriose. Sfhex was found to be a homodimer of 110 kDa in solution, with a pH optimum of 5.5. With a biantennary N-glycan substrate, it exhibited a 5-fold preference for removal of the beta(1,2)-linked N-acetylglucosamine from the Man alpha(1,3) branch compared with the Man alpha(1,6) branch. We isolated two corresponding cDNA clones for Sfhex that encode proteins with >99% amino acid identity. A phylogenetic analysis suggested that Sfhex is an ortholog of mammalian lysosomal beta-N-acetylhexosaminidases. Recombinant Sfhex expressed in Sf9 cells exhibited the same substrate specificity and pH optimum as the purified enzyme. Although a larger amount of newly synthesized Sfhex was secreted into the culture medium by Sf9 cells, a significant amount of Sfhex was also found to be intracellular. Under a confocal microscope, cellular Sfhex exhibited punctate staining throughout the cytoplasm, but did not colocalize with a Golgi marker. Because secretory glycoproteins and Sfhex are cotransported through the same secretory pathway and because Sfhex is active at the pH of the secretory compartments, this study suggests that Sfhex may play a role as a processing beta-N-acetylhexosaminidase acting on N-glycans from Sf9 cells.
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Affiliation(s)
- Noboru Tomiya
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
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9
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Lemieux MJ, Mark BL, Cherney MM, Withers SG, Mahuran DJ, James MNG. Crystallographic structure of human beta-hexosaminidase A: interpretation of Tay-Sachs mutations and loss of GM2 ganglioside hydrolysis. J Mol Biol 2006; 359:913-29. [PMID: 16698036 PMCID: PMC2910082 DOI: 10.1016/j.jmb.2006.04.004] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Revised: 03/30/2006] [Accepted: 04/01/2006] [Indexed: 11/21/2022]
Abstract
Lysosomal beta-hexosaminidase A (Hex A) is essential for the degradation of GM2 gangliosides in the central and peripheral nervous system. Accumulation of GM2 leads to severely debilitating neurodegeneration associated with Tay-Sachs disease (TSD), Sandoff disease (SD) and AB variant. Here, we present the X-ray crystallographic structure of Hex A to 2.8 A resolution and the structure of Hex A in complex with NAG-thiazoline, (NGT) to 3.25 A resolution. NGT, a mechanism-based inhibitor, has been shown to act as a chemical chaperone that, to some extent, prevents misfolding of a Hex A mutant associated with adult onset Tay Sachs disease and, as a result, increases the residual activity of Hex A to a level above the critical threshold for disease. The crystal structure of Hex A reveals an alphabeta heterodimer, with each subunit having a functional active site. Only the alpha-subunit active site can hydrolyze GM2 gangliosides due to a flexible loop structure that is removed post-translationally from beta, and to the presence of alphaAsn423 and alphaArg424. The loop structure is involved in binding the GM2 activator protein, while alphaArg424 is critical for binding the carboxylate group of the N-acetyl-neuraminic acid residue of GM2. The beta-subunit lacks these key residues and has betaAsp452 and betaLeu453 in their place; the beta-subunit therefore cleaves only neutral substrates efficiently. Mutations in the alpha-subunit, associated with TSD, and those in the beta-subunit, associated with SD are discussed. The effect of NGT binding in the active site of a mutant Hex A and its effect on protein function is discussed.
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Affiliation(s)
- M. Joanne Lemieux
- CIHR Group in Protein, Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada, T6G 2H7
| | - Brian L. Mark
- CIHR Group in Protein, Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada, T6G 2H7
| | - Maia M. Cherney
- CIHR Group in Protein, Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada, T6G 2H7
| | - Stephen G. Withers
- Chemistry Department, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - Don J. Mahuran
- Department of Laboratory, Medicine and Pathobiology, Sick Kids Hospital, 555, University Avenue, University of Toronto, Toronto, Ont., Canada M5G 1X8
| | - Michael N. G. James
- CIHR Group in Protein, Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada, T6G 2H7
- Corresponding author:
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10
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Mark BL, Mahuran DJ, Cherney MM, Zhao D, Knapp S, James MNG. Crystal structure of human beta-hexosaminidase B: understanding the molecular basis of Sandhoff and Tay-Sachs disease. J Mol Biol 2003; 327:1093-109. [PMID: 12662933 PMCID: PMC2910754 DOI: 10.1016/s0022-2836(03)00216-x] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In humans, two major beta-hexosaminidase isoenzymes exist: Hex A and Hex B. Hex A is a heterodimer of subunits alpha and beta (60% identity), whereas Hex B is a homodimer of beta-subunits. Interest in human beta-hexosaminidase stems from its association with Tay-Sachs and Sandhoff disease; these are prototypical lysosomal storage disorders resulting from the abnormal accumulation of G(M2)-ganglioside (G(M2)). Hex A degrades G(M2) by removing a terminal N-acetyl-D-galactosamine (beta-GalNAc) residue, and this activity requires the G(M2)-activator, a protein which solubilizes the ganglioside for presentation to Hex A. We present here the crystal structure of human Hex B, alone (2.4A) and in complex with the mechanistic inhibitors GalNAc-isofagomine (2.2A) or NAG-thiazoline (2.5A). From these, and the known X-ray structure of the G(M2)-activator, we have modeled Hex A in complex with the activator and ganglioside. Together, our crystallographic and modeling data demonstrate how alpha and beta-subunits dimerize to form either Hex A or Hex B, how these isoenzymes hydrolyze diverse substrates, and how many documented point mutations cause Sandhoff disease (beta-subunit mutations) and Tay-Sachs disease (alpha-subunit mutations).
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Affiliation(s)
- Brian L. Mark
- Canadian Institutes of Heath Research Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alt.,Canada T6G 2H7
| | - Don J. Mahuran
- The Research Institute, The Hospital for Sick Children, 555 University Ave, Toronto Ont., Canada M5G1X8
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ont., Canada M5G1L6
| | - Maia M. Cherney
- Canadian Institutes of Heath Research Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alt.,Canada T6G 2H7
| | - Dalian Zhao
- Department of Chemistry, Rutgers University, New Brunswick, NJ 08903, USA
| | - Spencer Knapp
- Department of Chemistry, Rutgers University, New Brunswick, NJ 08903, USA
| | - Michael N. G. James
- Canadian Institutes of Heath Research Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alt.,Canada T6G 2H7
- Corresponding author:
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11
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Affiliation(s)
- R L Proia
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Mahuran DJ, Gravel RA. The beta-hexosaminidase story in Toronto: from enzyme structure to gene mutation. ADVANCES IN GENETICS 2002; 44:145-63. [PMID: 11596980 DOI: 10.1016/s0065-2660(01)44077-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- D J Mahuran
- The Research Institute, The Hospital for Sick Children and Department of Laboratory Medicine and Pathobiology University of Toronto, Ontario, Canada.
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13
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Neufeld EF, d'Azzo A. Biosynthesis of normal and mutant beta-hexosaminidases. ADVANCES IN GENETICS 2002; 44:165-71. [PMID: 11596981 DOI: 10.1016/s0065-2660(01)44078-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- E F Neufeld
- Department of Biological Chemistry, UCLA School of Medicine, Los Angeles, California 90095, USA.
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14
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Hepbildikler ST, Sandhoff R, Kolzer M, Proia RL, Sandhoff K. Physiological substrates for human lysosomal beta -hexosaminidase S. J Biol Chem 2002; 277:2562-72. [PMID: 11707436 DOI: 10.1074/jbc.m105457200] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human lysosomal beta-hexosaminidases remove terminal beta-glycosidically bound N-acetylhexosamine residues from a number of glycoconjugates. Three different isozymes composed of two noncovalently linked subunits alpha and beta exist: Hex A (alphabeta), Hex B (betabeta), and Hex S (alphaalpha). While the role of Hex A and B for the degradation of several anionic and neutral glycoconjugates has been well established, the physiological significance of labile Hex S has remained unclear. However, the striking accumulation of anionic oligosaccharides in double knockout mice totally deficient in hexosaminidase activity but not in mice expressing Hex S (Sango, K., McDonald, M. P., Crawley, J. N., Mack, M. L., Tifft, C.J., Skop, E., Starr, C. M., Hoffmann, A., Sandhoff, K., Suzuki, K., and Proia, R. L., (1996) Nat. Genet. 14, 348-352) prompted us to reinvestigate the substrate specificity of Hex S. To identify physiological substrates of Hex S, anionic and neutral oligosaccharides excreted in the urine of the double knockout mice were isolated and analyzed. Using ESI-MS/MS and glycosidase digestion the anionic glycans were identified as products of incomplete dermatan sulfate degradation whereas the neutral storage oligosaccharides were found to be fragments of N-glycan degradation. In vitro, recombinant Hex S was highly active on water-soluble and amphiphilic glycoconjugates including artificial substrates, sulfated GAG fragments, and the sulfated glycosphingolipid SM2. Hydrolysis of membrane-bound SM2 by the recombinant Hex S was synergistically stimulated by the GM2 activator protein and the lysosomal anionic phospholipid bis(monoacylglycero)phosphate.
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Affiliation(s)
- Stefan T Hepbildikler
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
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15
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Schmid JA, Mach L, Paschke E, Glössl J. Accumulation of sialic acid in endocytic compartments interferes with the formation of mature lysosomes. Impaired proteolytic processing of cathepsin B in fibroblasts of patients with lysosomal sialic acid storage disease. J Biol Chem 1999; 274:19063-71. [PMID: 10383408 DOI: 10.1074/jbc.274.27.19063] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The impact of an altered endocytic environment on the biogenesis of lysosomes was studied in fibroblasts of patients suffering from sialic acid storage disease (SASD). This inherited disorder is characterized by the accumulation of acidic monosaccharides in lysosomal compartments and a concomitant decrease of their buoyant density. We demonstrate that C-terminal trimming of the lysosomal cysteine proteinase cathepsin B is inhibited in SASD fibroblasts. This late event in the biosynthesis of cathepsin B normally takes place in mature lysosomes, suggesting an impaired biogenesis of these organelles in SASD cells. When normal fibroblasts are loaded with sucrose, which inhibits transport from late endosomes to lysosomes, C-terminal cathepsin B processing is prevented to the same extent. Further characterization of the terminal endocytic compartments of SASD cells revealed properties usually associated with late endosomes/prelysosomes. In addition to a decreased buoyant density, SASD "lysosomes" show a reduced acidification capacity and appear smaller than their normal counterparts. We conclude that the accumulation of small non-diffusible compounds within endocytic compartments interferes with the formation of mature lysosomes and that the acidic environment of the latter organelles is a prerequisite for C-terminal processing of lysosomal hydrolases.
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Affiliation(s)
- J A Schmid
- Centre of Applied Genetics, University of Agricultural Sciences, Vienna A-1190, Austria.
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16
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Chapter 1a Normal and pathological catabolism of glycoproteins. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0167-7306(08)60278-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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17
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Liessem B, Glombitza GJ, Knoll F, Lehmann J, Kellermann J, Lottspeich F, Sandhoff K. Photoaffinity labeling of human lysosomal beta-hexosaminidase B. Identification of Glu-355 at the substrate binding site. J Biol Chem 1995; 270:23693-9. [PMID: 7559539 DOI: 10.1074/jbc.270.40.23693] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The carbene precursor 3-azi-1-[([6-3H]-2-acetamido-2-deoxy-1-beta-D-galactopyranosyl)thi o -butane (also designated [3H]-1-ATB-GalNAc) has been used as a photoaffinity label for human lysosomal beta-hexosaminidase B (Hex B, EC 3.2.1.52) purified to apparent homogeneity from postmortal liver. [3H]-1-ATB-GalNAc behaved as an active site-directed inhibitor, which bound covalently to Hex B upon photolysis at 350 nm and resulted in 15% inactivation of enzyme activity. Up to 75% of the inactivation of Hex B was prevented by including the competitive inhibitor 2-acetamido-2-deoxy-D-glucono-1,5-lactone in the photoaffinity experiment. Incubation of [3H]-1-ATB-GalNAc with the enzyme followed by irradiation and subsequent separation of the three polypeptides composing the beta-subunit led mainly to labeling of the beta a-polypeptide. Subsequent proteolysis of beta a with trypsin and separation of the resulting peptides by high pressure liquid chromatography yielded one prominently labeled peptide fraction. Edman degradation resulted in the sequence E339ISEVFPDQFIHLGGD-EVEFK359. However, no modified amino acid was detected, indicating that the photoaffinity label was presumably bound to the peptide by a labile ester linkage. This was proven when the radiolabel was almost completely released from the peptide by treatment with aqueous ammonium hydroxide. Simultaneously, Glu-355 was converted into Gln-355, which is located within a region of Hex B that shows considerable homology with the alpha-subunit of human hexosaminidase A and other hexosaminidases from various species.
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Affiliation(s)
- B Liessem
- Institut für Organische Chemie und Biochemie, Universität Bonn, Federal Republic of Germany
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18
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Abstract
The lysosomal enzyme beta-hexosaminidase (Hex, EC 3.2.1.52) was purified from human serum and placental tissue. On gel chromatography, Hex isoenzymes (Hex A, B and P) from serum showed a molecular weight of about 150 kDa, i.e. higher than the 120 kDa found for the placental (tissue) isoenzymes (Hex A and B). Sodium dodecyl sulphate polyacrylamide gel electrophoresis of non-reduced serum Hex A revealed two different subunits, denoted alpha and beta, corresponding to apparent molecular weights of 70 and 67 kDa, respectively. Serum Hex B and Hex P were composed of beta-subunits only. In contrast, the apparent molecular weights of the alpha- and beta-subunits originating from tissue were both 55 kDa. Reduction of tissue Hex A and Hex B resulted in cleavage of the beta-subunit into several fragments, whereas the beta-subunit in serum forms was resistant to this treatment. These results are consistent with the serum forms never having entered the lysosome prior to their release to the extracellular environment and serum forms can therefore be classified as precursor molecules. No mature (tissue) forms were found in serum. Isoelectric focusing before and after neuraminidase treatment of the serum isoenzymes showed that they all contained sialic acid and that Hex B and Hex P had an identical focusing pattern after desialylation. Serum beta-hexosaminidase is frequently elevated in liver disease, alcoholism and pregnancy and the results of the present study indicate that this is due to an increased synthesis and secretion of hypersialylated beta-subunits, rather than to release of intralysosomally stored enzyme.
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Affiliation(s)
- A Isaksson
- Department of Clinical Chemistry, University Hospital, Lund, Sweden
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19
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Martino S, Emiliani C, Orlacchio A, Hosseini R, Stirling JL. Beta-N-acetylhexosaminidases A and S have similar sub-cellular distributions in HL-60 cells. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1243:489-95. [PMID: 7727524 DOI: 10.1016/0304-4165(94)00179-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In HL-60 cells the most abundant isoenzymes of beta-N-acetyl-hexosaminidase are A (alpha beta) and S (alpha alpha). Sub-cellular fractionation of HL-60 cells by differential centrifugation showed that both A and S forms were present in the lysosomal and post-lysosomal (soluble) fractions in approximately equal abundance. Ion-exchange chromatography showed that a fraction enriched with plasma membranes had the A form, and a form of beta-N-acetylhexosaminidase less acidic than A, but there was no S. Analysis of the alpha-subunits of beta-N-acetylhexosaminidases A and S using Western blotting and immuno-detection with antisera raised to synthetic peptides showed that mature alpha-subunits were present in both A and S isolated from the lysosomal fraction. This observation establishes that the alpha alpha-dimer of beta-N-acetyl-hexosaminidase (S) can be transported to lysosomes in HL-60 cells whereas there is good evidence that this does not take place in fibroblasts. HL-60 cells were not stimulated to secrete lysosomal enzymes by incubating them with NH4Cl and, unlike fibroblasts, are unlikely to use mannose-6-phosphate mediated transport of beta-N-acetylhexosaminidases to lysosomes. Comparison of the sequence of the beta-N-acetylhexosaminidase alpha-subunit with a 43 amino acid sequence of cathepsin D, though to function in the mannose-6-phosphate independent targeting of this enzyme to lysosomes, showed alignment in a region towards the C-terminus in which 21% of the residues were identical with the interposition of a one amino acid gap.
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Affiliation(s)
- S Martino
- Division of Life Sciences, King's College London, Campden Hill, UK
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20
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Mahuran DJ. Beta-hexosaminidase: biosynthesis and processing of the normal enzyme, and identification of mutations causing Jewish Tay-Sachs disease. Clin Biochem 1995; 28:101-6. [PMID: 7628066 DOI: 10.1016/0009-9120(95)00003-r] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES This report presents an overview of the nearly 100-year history of the study of Tay-Sachs disease in the Ashkenazi Jewish population. DESIGN AND METHODS Each major step leading to our present understanding of the disease are highlighted. RESULTS The original interest in the cause of this devastating disease in the late 1800s led to the identification of a novel glycolipid. GM2 ganglioside, stored in the neurons of Tay-Sachs patients in the 1930s, and the elucidation of its structure in the 1960s. The identification of the defective isozyme, beta-hexosaminidase A, followed in 1968-69. Elucidation of the subunit structures of the hexosaminidase A (alpha beta) and B (beta beta) isozymes in 1973 and their purification in 1974-80, led to the characterization of the biosynthesis, assembly, intracellular transport, and posttranslational processing of the two subunits in the 1980s. The ability to purify milligram quantities of the isozymes made possible the isolation of cDNA clones encoding both subunits in 1985, and ultimately the identification of the causes of Jewish Tay-Sachs disease at the genomic DNA level in 1988. CONCLUSIONS Tay-Sachs disease is the major model for lysosomal storage diseases. Similarly, the work done in the 1980s on hexosaminidase has been used as a model for understanding the cell biology of many other lysosomal proteins. Current research encompassing the fields of enzymology, cell biology, and molecular biology is linking genotypes with the clinical phenotypes of patients with Tay-Sachs and related diseases.
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Affiliation(s)
- D J Mahuran
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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21
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Abstract
beta-Hexosaminidase is a lysosomal hydrolase that is important in the metabolism of sphingoglycolipids. beta-Hexosaminidase B and beta-hexosaminidase A are the major isozymes in normal human tissue. beta-Hexosaminidase B is a homodimer of beta subunits, and beta-hexosaminidase A is a heterodimer composed of an alpha and a beta subunit. Crystals of beta-hexosaminidase B (M(r) 112,000) have been grown using the handling drop technique. They are elongated hexagonal prisms with maximum dimensions of 0.2 mm x 0.2 mm x 0.7 mm. The space group is P6(1)22 (or enantiomorph); the unit cell dimensions are a = b = 114.2 A, c = 402.2 A, alpha = beta = 90 degrees, gamma = 120 degrees. The molecular mass and cell dimensions suggest that there is one dimer per asymmetric unit. Crystals diffract to 3.2 A resolution.
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Affiliation(s)
- W B Church
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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22
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Hasilik A. The early and late processing of lysosomal enzymes: proteolysis and compartmentation. EXPERIENTIA 1992; 48:130-51. [PMID: 1740186 DOI: 10.1007/bf01923507] [Citation(s) in RCA: 123] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lysosomal enzymes are subjected to a number of modifications including carbohydrate restructuring and proteolytic maturation. Some of these reactions support lysosomal targeting, others are necessary for activation or keeping the enzyme inactive before being segregated, while still others may be adventitious. The non-segregated fraction of the enzyme is secreted and can be isolated from the medium. It is considered that the secreted lysosomal enzymes fulfill certain physiological and pathophysiological roles. By comparing the secreted and the intracellular enzymes it is possible to distinguish between the reactions that occur before and after the segregation. In this review the reactions that may influence the segregation are referred to as the early processing and those characteristic for the enzymes isolated from lysosomal compartments as the late processing. The early processing is characterized mainly by modifications of carbohydrate side chains. In the late processing, proteolytic fragmentation represents the most conspicuous changes. The review focuses on the compartmentation of the reactions and the proteolytic fragmentation of lysosomal enzyme precursors. While a plethora of proteolytic reactions are involved, our knowledge of the proteinases responsible for the particular maturation reactions remains very limited. The review points also to work with cells from patients affected with lysosomal storage disorders, which contributed to our understanding of the lysosomal apparatus.
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Affiliation(s)
- A Hasilik
- Institute for Physiological Chemistry and Pathobiochemistry, University of Münster, Germany
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23
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Abstract
Tay-Sachs disease is one of the few neurodegenerative diseases of known causes. It results from mutations of the HEXA gene encoding the alpha subunit of beta-hexosaminidase, producing a destructive ganglioside accumulation in lysosomes, principally in neurons. With the determination of the protein sequence of the alpha and beta subunits, deduced from cDNA sequences, the complex pathway of subcellular and lysosomal processing of the enzyme has been determined. More recently, detailed knowledge of the gene structure has allowed the determination of specific mutations causing Tay-Sachs disease. The high incidence of the disease in Ashkenazi Jews is attributed predominantly to three mutations present in high frequency, while in non-Jews some two dozen mutations have been identified thus far. The cataloguing of mutations has important implications for carrier screening and prenatal diagnosis for Tay-Sachs disease.
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Affiliation(s)
- R A Gravel
- McGill University-Montreal Children's Hospital Research Institute, Quebec, Canada
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24
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Fisher K, Aronson N. Characterization of the mutation responsible for aspartylglucosaminuria in three Finnish patients. Amino acid substitution Cys163—-Ser abolishes the activity of lysosomal glycosylasparaginase and its conversion into subunits. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99071-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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25
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Mahuran DJ. The biochemistry of HEXA and HEXB gene mutations causing GM2 gangliosidosis. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1096:87-94. [PMID: 1825792 DOI: 10.1016/0925-4439(91)90044-a] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- D J Mahuran
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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26
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Neote K, Brown CA, Mahuran DJ, Gravel RA. Translation initiation in the HEXB gene encoding the beta-subunit of human beta-hexosaminidase. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)45286-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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27
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Dlott B, d'Azzo A, Quon DV, Neufeld EF. Two mutations produce intron insertion in mRNA and elongated beta-subunit of human beta-hexosaminidase. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)38251-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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28
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Characterization of human placental beta-hexosaminidase I2. Proteolytic processing intermediates of hexosaminidase A. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39219-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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29
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Brown CA, Neote K, Leung A, Gravel RA, Mahuran DJ. Introduction of the α subunit mutation associated with the B1 variant of Tay-Sachs disease into the β subunit produces a β-hexosaminidase B without catalytic activity. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(20)88243-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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30
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A Frameshift Mutation in a Patient with Tay-Sachs Disease Causes Premature Termination and Defective Intracellular Transport of the α-Subunit of β-Hexosaminidase. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)30090-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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31
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Neufeld EF. Natural History and Inherited Disorders of a Lysosomal Enzyme, β-Hexosaminidase. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)60406-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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32
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Analysis of the glycosylation and phosphorylation of the lysosomal enzyme, β-hexosaminidase B, by site-directed mutagenesis. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)83290-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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33
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Daniel WL, Kahle EJ. Arylsulfatase and beta-glucuronidase expression in green sunfish, bluegill, and their reciprocal interspecific hybrids. Biochem Genet 1989; 27:167-81. [PMID: 2775168 DOI: 10.1007/bf02401799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Fish arylsulfatases (arylsulfate sulfohydrolase; EC 3.1.6.1) were resolved into cationic arylsulfatase A-like (ARSA) and anionic arylsulfatase B-like (ARSB) fractions by DEAE-Sephacel chromatography. Green sunfish (GSF) hepatic ARSA was more acidic and more thermostable than bluegill (BG) ARSA. GSF x BG interspecific hybrids preferentially expressed GSF ARSA, while BG x GSF hybrids appeared to produce a dimeric enzyme consisting of both GSF and BG ARSA polypeptides. GSF hepatic beta-glucuronidase (GUS) also proved to be more thermostable than BG GUS. Thermostabilities of GUS produced by reciprocal interspecific hybrids were very similar to that of GSF GUS. Either GSF GUS is preferentially expressed in both interspecific hybrids or both the GSF and BG GUS polypeptides are synthesized in comparable amounts, and the GSF GUS polypeptide sufficiently stabilizes the heterotetramers produced by the hybrids to produce denaturation profiles closely approximating that of the GSF enzyme.
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Affiliation(s)
- W L Daniel
- Department of Cell and Structural Biology, University of Illinois, Urbana 61801
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34
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Arylsulfatase and beta-glucuronidase expression in green sunfish, bluegill, and their reciprocal interspecific hybrids. Biochem Genet 1989. [DOI: 10.1007/pl00020153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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35
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Quon DVK, Proia RL, Fowler AV, Bleibaum J, Neufeld EF. Proteolytic Processing of the β-Subunit of the Lysosomal Enzyme, β-Hexosaminidase, in Normal Human Fibroblasts. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)94077-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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36
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37
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Robertson DA, Freeman C, Nelson PV, Morris CP, Hopwood JJ. Human glucosamine-6-sulfatase cDNA reveals homology with steroid sulfatase. Biochem Biophys Res Commun 1988; 157:218-24. [PMID: 3196333 DOI: 10.1016/s0006-291x(88)80035-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Glucosamine-6-sulfatase is a lysosomal enzyme which degrades glycosaminoglycans and is deficient in mucopolysaccharidosis type IIID. Human liver contains two major active forms of glucosamine-6-sulfatase, form A which has a single 78 kDa polypeptide and form B which has two polypeptides of 48 kDa and 32 kDa. A 1761 base pair cDNA clone encoding the complete 48 kDa polypeptide of form B was isolated. Form A is shown to be processed to form B with the 48 kDa polypeptide C-terminal to the 32 kDa polypeptide, and it is shown that C-terminal processing is limited to a region of thirty amino acids. The glucosamine-6-sulfatase sequence reveals homology with steroid sulfatase, a microsomal enzyme.
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Affiliation(s)
- D A Robertson
- Department of Chemical Pathology, Adelaide Children's Hospital, South Australia
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38
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Yonezawa S, Takahashi T, Wang XJ, Wong RN, Hartsuck JA, Tang J. Structures at the proteolytic processing region of cathepsin D. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37621-x] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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39
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Bapat B, Ethier M, Neote K, Mahuran D, Gravel RA. Cloning and sequence analysis of a cDNA encoding the beta-subunit of mouse beta-hexosaminidase. FEBS Lett 1988; 237:191-5. [PMID: 2971567 DOI: 10.1016/0014-5793(88)80199-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A cDNA encoding the prepro-beta-polypeptide of mouse beta-hexosaminidase (Hex) was isolated from a mouse lymphoblast cDNA library. The cDNA contains an open reading frame corresponding to a polypeptide of 536 amino acids which shows 74% homology with the human prepro-beta-polypeptide. An examination of the amino acid sequence identifies a putative signal peptide and five possible glycosylation sites, two of which are identical to the confirmed glycosylation sites of the human beta-chain. The amino acid sequence also shows a structurally similar though not identical site for internal cleavage responsible for the generation of mature beta a- and beta b-polypeptides.
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Affiliation(s)
- B Bapat
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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40
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Synthesis and assembly of a catalytically active lysosomal enzyme, beta-hexosaminidase B, in a cell-free system. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37728-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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