GABARAP-artige Proteine, Nix und Bcl-2 : strukturelle Basis molekularer Interaktionen an der Schnittstelle zwischen Autophagie und Apoptose
GABARAP-artige Proteine, Nix und Bcl-2 : strukturelle Basis molekularer Interaktionen an der Schnittstelle zwischen Autophagie und Apoptose
Autophagy, a pathway primarily relevant for cell survival, and apoptosis, a process leading to cell death, are the two main mechanisms of self-destruction at cellular and subcellular levels. Currently, a potential crosstalk between apoptosis and autophagy is intensively discussed, the respective pro...
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Personal Name(s): | Schwarten, Melanie (Corresponding author) |
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Contributing Institute: |
Strukturbiochemie; ICS-6 |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentrlbibliothek, Verlag
2011
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Physical Description: |
VIII, 164 S |
Dissertation Note: |
Universität Düsseldorf, Diss., 2010 |
ISBN: |
978-3-89336-700-9 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
Addenda |
Series Title: |
Schriften des Forschungszentrums Jülich. Reihe Gesundheit / Health
34 |
Subject (ZB): | |
Publikationsportal JuSER |
Autophagy, a pathway primarily relevant for cell survival, and apoptosis, a process leading to cell death, are the two main mechanisms of self-destruction at cellular and subcellular levels. Currently, a potential crosstalk between apoptosis and autophagy is intensively discussed, the respective protein-protein interaction network, however, remains to be elucidated in detail. The $\gamma$-aminobutyric acid type A (GABA$_{A}$) receptor-associated protein GABARAP belongs to a family of proteins implicated in intracellular transport events and autophagy. It encompasses several mammalian members like GABARAP and MAP LC3 (microtubuleassociated protein 1 light chain 3) as well as the yeast protein Atg8 (autophagy-related protein 8). The members of the GABARAP-like family belong to the Ubiquitin-like modifiers and are enzymatically coupled to the phospholipids phosphatidylethanolamine (PE) or phosphatidylserine (PS) via a multiple-stage mechanism. During the first processing step GABARAP-like proteins get truncated at the carboxy termini. In the present work, the solution structure of unprocessed Atg8 was determined. In addition, the dynamical behaviour of the unprocessed and the truncated form were compared. Unprocessed Atg8 features a ubiquitin-like domain and a N-terminal domain, that undergoes conformational exchange on the micro- to millisecond timescale. Cleavage of the C-terminal arginine residue does not stabilise one conformation in the N-terminal domain, but increases the rigidity of the ubiquitin-like domain. Further increase in rigidity can be expected upon lipidation. This and the conformation exchange in the N-terminal region may favour oligomerization of lipidated Atg8 to mediate autophagosome formation. Based on a phage display screen, nip-like protein x (Nix) was identified to be a potential binding partner of GABARAP. Most recognized is the role of Nix in apoptosis, where it contributes to cell death. In the present work, the molecular basis of the binding reaction of GABARAP and Nix was quantitatively investigated by surface plasmon resonance (SPR) experiments. The dissociation constant K$_{D}$ of the complex is about 100 μM. Structural information about the Nix binding area on GABARAP was obtained by NMR spectroscopy. This binding area includes the hydrophobic pockets 1 and 2. Thus, the specific interaction between Nix and GABARAP indicates one of the first elucidated molecular links between autophagy and apoptosis. [...] |