Untersuchung von Tubulin-Polyglutamylierung/-Deglutamylierung in der Regulation synaptischer Transportprozesse sowie deren Einfluß auf Lernen und Gedächtnis.
Final Report Abstract
Polyglutamylation (poly-Glu) of tubulin is a posttranslational modification of microtubules, which is thought to affect the binding of microtubule-associated proteins and motor proteins with the cytoskeleton. Little is known about the role of poly-Glu in cytoskeletal transport. We observed preliminary results, suggesting that poly-Glu affects the motor-cargo delivery of synaptic proteins. The aim of the project was to study synaptic trafficking and cognitive function in a genetic mouse model with reduced poly-Glu levels. We established a knockout mouse of the major neuronal polyglutamylase TTLL1 by using animals provided by the European Mouse Mutant Archive EMMA. After extensive characterization it turned out that these mice were genetically incorrect and may carry a phantom allele. Therefore, we had to take an alternative approach. We successfully generated three knock-in mouse mutant lines by our own, which carry point mutations in the tubulin C-terminal tail to abolish polyglutamylation. In parallel, we established live cell imaging with a spinning disk microscope to visualize neuronal transport in live. The characterization of marker proteins for anterograde and retrograde transport of synaptic receptors are suitable for studying poly-Glu-dependent transport. We also developed mouse behavioral assays in the lab to study poly-Glu mouse mutants in cognition. These experiments are available for in vivo analysis of the respective mutant lines. Although the original aims could not be reached in the funding period, we finally generated and established the required animals and assays. It is expected that we will now be able to finish our original aims in a reasonable time scale.
Publications
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GRIP1 interlinks N-cadherin and AMPA receptors at vesicles to promote combined cargo transport into dendrites. Proc Natl Acad Sci USA. 2014 Apr 1;111(13):5030-5
Heisler FF, Lee HK, Gromova KV, Pechmann Y, Schurek B, Ruschkies L, Schroeder M, Schweizer M, Kneussel M
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The kinesin KIF21B participates in the cell surface delivery of γ2 subunit-containing GABAA receptors. Eur J Cell Biol. 2014 Aug-Sep;93(8-9):338-46
Labonté D, Thies E, Kneussel M
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. The LisH motif of muskelin is crucial for oligomerization and governs intracellular localization. Structure. 2015 Feb 3;23(2):364-73
Delto CF, Heisler FF, Kuper J, Sander B, Kneussel M, Schindelin H
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GSK3 and KIF5 regulate activity-dependent sorting of gephyrin between axons and dendrites. Eur J Cell Biol. 2015 Mar-Apr;94(3-4):173-8
Rathgeber L, Gromova KV, Schaefer I, Breiden P, Lohr C, Kneussel M
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Radixin regulates synaptic GABAA receptor density and is essential for reversal learning and short-term memory. Nat Commun. 2015 Apr 20;6:6872
Hausrat TJ, Muhia M, Gerrow K, Thomas P, Hirdes W, Tsukita S, Heisler FF, Herich L, Dubroqua S, Breiden P, Feldon J, Schwarz JR, Yee BK, Smart TG, Triller A, Kneussel M
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Structure-function-behavior relationship in estrogen-induced synaptic plasticity. Horm Behav. 2015 May 23 [Epub ahead of print]
R Vierk, Bayer J, Freitag S, Muhia M, Kutsche K, Wolbers T, Kneussel M, Sommer T, Rune GM
