Pathomechanisms of lysosomal storage disorders
Project Leader: Thomas Braulke
- Project Mucolipidosis II
- Project NCL2TREAT
- Team
- Publications
- Funding
- Links
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Project Mucolipidosis II
Mouse model for mucolipidosis II alpha/beta
We have generated a knock-in mouse model of MLII. In this mouse a single cytosine was inserted in the Gnptab gene (c.3082insC) that is predicted to cause a premature translational termination in the C-terminal conserved region (p.G1028RfsX16) (Figure F 1, Kollmann, et al., 2010). This mutation corresponds to the human c.3145insC mutation (p.G1049RfsX16) detected in an MLII alpha/beta patient (Tiede et al. 2005a).Figure F1. The predicted domain structure of the human alpha/beta-subunit precursor protein of the GlcNAc-1-phosphotransferase was compared with the mouse knock-in mutant (p.G1028RfsX16) alpha/beta-subunit precursors. The red part in the C-terminal conserved domain of the mutant alpha/beta-subunit precursor represents the 16 additional amino acids.
In fibroblasts of this MLII alpha/beta patient no GlcNAc-1-phosphotransferase activity was measured, associate with a strong intracellular reduction of several lysosomal enzyme activities. Mouse embryonic fibroblasts prepared from mutant c.3082insC knock-in mice exhibit intracellular deficiencies and hypersecretion of multiple lysosomal enzyme activities (Figure F2A, Kollmann, et al., 2010) confirming biochemically the MLII-phenotype. Aditionally, no M6P-containing proteins were detectable in cell extracts analyzed by scFv M6P-1 western blotting (Figure F2B, Kollmann, et al., 2010, Müller-Loennies, et al. 2010).
Figure F2: Relative enzyme activities of lysosomal hydrolases beta-hexosaminidase (beta-hex), alpha-mannosidase (alpha-man) and beta-galactosidase (beta-gal) measured in homogenates of mouse embryonic fibroblasts from c.3082insC knock-in mice in comparison to activities in wild-type fibroblasts. The lysosomal hydrolase activities are reduced in the mutant cells (A). Extracts from c.3082insC knock-in mouse embryonic fibroblasts (ki/ki), from heterozygous (wt/ki) and wild-type fibroblasts (wt/wt) and aliquots of media conditioned for 24 h were analyzed by scFv M6P-1 western blotting. In wild-type cells several M6P-containing proteins were observed whereas in c.3082insC cells no M6P-specific signals were detectable demonstrating the loss of GlcNAc-1-phosphotransferase activity in the knock-in cells (B).
This mouse model will allow the analysis of pathomechanisms in MLII and related lysosomal storage diseases and the investigation of alternative M6P-independent transport routes to lysosomes.
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Project NCL2TREAT
For detailed information please visit the NCL2TREAT homepage
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Team
Project Leader
Prof. Dr. rer. nat.Thomas BraulkePhoneE-mailPostdoctoral Fellows
Dr. rer. nat.Malte KlüssendorfPhoneE-mailScientific Staff / Graduate Students
Cand. med. Svenja Krambeck
Former Members
Dr. rer. nat. Stephan Tiede
Dr. med. Elisabeth Schöne
Dr. rer. nat. Nina Westphal
Cinta Diez-Ardanuy, PhD
Dr. rer. nat. Georgia Makrypidi
Andrea Pirosu, MSc
Dr. rer. nat. Sandra Markmann
Dr. med. Takanobu Otomo
Dr. rer. nat. Katrin Kollmann
Dr. med. Kathrin Karkmann
Dr. rer. nat. Melanie Thelen
Dr. rer. nat. Katrin Marschner
Dr. med. Bastian Thies
Dr. rer. nat. Annika Kurze
Dr. rer. nat. Giovanna Galliciotti
Cand. med. Anna-Katharina Röchert
Dr. rer. nat. Anne-Hélène Lebrun
Inke Stange (TA)
Dr. med. Nicole Muschol
Dr. rer. nat. Britta Keyser
Dr. med. Brit Hofmann
Manuel-Álvaro Berbis-Moreno
Monica Castrichini, PhD
Dipl-Biol. Guillermo F. Jofre
Dr. rer. nat. Arne Quitsch
Dr. rer. nat. Sabrina Jabs
Dr. med. Franziska Stellmer
Dr. rer. nat. Bettina Koch
Dr. rer. nat. Bernd Kübler
Dr. rer. nat. Sandra Oesterreicher
Dr. rer. nat. Nicola Ott
Dr. rer. nat. Claudia Heine
Dr. med. Bettina Bertram
Dr. med. Victoria Schebek-Fürstenberg
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Publications
Project-relevant Publications
- Impaired bone remodeling and its correction by combination therapy in a mouse model of mucopolysaccharidosis-I. Kuehn SC, Koehne T, Cornils K, Markmann S, Riedel C, Pestka JM, Schweizer M, Baldauf C, Yorgan TA, Krause M, Keller J, Neven M, Breyer S, Stuecker R, Muschol N, Busse B, Braulke T, Fehse B, Amling M, Schinke T (2015) Hum Mol Genet 24:7075-86 Abstract
- Mannose 6-phosphorylation of lysosomal enzymes controls B-cell functions. Otomo T, Schweizer M, Kollmann K, Schumacher V, Muschol N, Tolosa E, Mittrücker HW, Braulke T* (2015) J Cell Biol 208:171-180 Abstract
- Lrp1/LDL Receptor Play Critical Roles in Mannose 6-Phosphate-Independent Lysosomal Enzyme Targeting. Markmann S, Thelen M, Cornils K, Schweizer M, Brocke-Ahmadinejad N, Willnow T, Heeren J, Gieselmann V, Braulke T, Kollmann K (2015) Traffic 16:743-59 Abstract
- Mannose 6-phosphate-independent Lysosomal Sorting of LIMP-2. Blanz J, Zunke F, Markmann S, Damme M, Braulke T, Saftig P, Schwake M (2015) Traffic 16:1127-36 Abstract
- Increased osteoclastogenesis rather than missorting of lysosomal enzymes is causing bone loss in mucolipidosis II. Kollmann K, Pestka JM, Schöne E, Schweizer M, Karkmann K, Kühn SC, Catala-Lehnen P, Failla AV, Marshall RP, Krause M, Santer R, Amling M, Braulke T*, Schinke T* (2013) EMBO Mol Med 5:1871-1886 Abstract
- Lysosomal dysfunction causes neurodegeneration in mucolipidosis II 'knock-in' mice. Kollmann K, Damme M, Markmann S, Morelle W, Schweizer M, Hermans-Borgmeyer I, Röchert AK, Pohl S, Lübke T, Michalski J-C, Käkelä R, Walkley SU, Braulke T* (2012) Brain 135:2661-2675 Abstract
- A key enzyme in the biogenesis of lysosomes is a protease that regulates cholesterol metabolism. Marschner K, Kollmann K, Schweizer M, Braulke T*, Pohl S (2011) Science 333:87-90 Abstract
- Mucolipidosis II is caused by mutations in GNPTA encoding the alpha/beta GlcNAc-1-phosphotransferase. Tiede S, Storch S, Lübke T, Henrissat B, Bargal R, Raas-Rothschild A, Braulke T* (2005) Nat Med 11:1109-1112 Abstract
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Funding
10/2017 - 09/2020
German Research Foundation (DFG)
Research Unit 2625:
"Mechanisms of Lysosomal Homeostasis"
www.for2625-lysosomes.de02/2016 - 01/2019
Federal Ministry of Education and Research (BMBF)
NCL2TREAT: A network for coordinated research and development of clinical biomarkers, diagnostics, pathomechanisms and therapeutic strategies for neuronal ceroid lipofuscinoses
www.ncl2treat.de
01/2016 - 12/2018
EU Horizon 2020
BATCure: European network for coordinated research on neuronal ceroid lipofuscinosis
Website BATCure
07/2010 - 06/2018
German Research Foundation (DFG)
Collaborative Research Centre 877:
"Proteolysis as a Regulatory Event in Pathophysiology"
www.uni-kiel.de/Biochemie/sfb877/
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Links