Publikationsserver der RWTH Aachen University
Identifizierung und Kartierung von nukleären Import- und Exportsignalmotiven innerhalb des Y-box-bindenden Proteins-1 (YB-1)
Abstract
dc:descriptionY-box Protein-1 (YB-1) is a multifunctional protein, which binds to DNA and RNA thereby influencing transcription and transplation. YB-1 consists of three domains: the N-terminal glycine-rich sequence, the cold shock domain (CSD) and the C-terminal domain. The latter contains alternating acidic and basic amino acids and takes part in a number of protein-protein interactions. Shuttel between the cell nucleus and cytoplasm is essential for YB-1 functionality. In immortalized and proliferationg cells YB-1 is localised in cytoplasm. After stimulation with cytotoxic agents, under hyperthermia or ultraviolet light YB-1 translocates to the nucleus. Accumulation of YB-1 in nuclei of malignant cells is associated with a bad prognosis and higher rate of metastasis in patients with various tumors. In the course of the anti-Thy1.1 nephritis, an animal model of inflammatory renal disease, YB-1 accumulates in cytoplasm of mesangial cells. This accumulation correlates with the mesangial cell proliferation and activation between the days four of the anti-Thy1.1 nephritis. Following day nine up till restitution of nehritis a gradual nuclear re-localisation of YB-1 is observed. In this work, the subcellular localisation of YB-1 domains was examined. To localize the nuclear import and export sequences of YB-1 protein, various YB-1 deletion constructs and stimulations were used in different cell lines. Mutation studies showed that both Nuclear Localisation Sequences (NLS) of the bipartite NLS 276-292 are required for nuclear localisation. On the other hand, the length of the sequence between both NLS components or the tyrosine residues had no effect on nuclear YB-1 localisation. Sorokin et al.showed that YB-1 is cleaved at the amino acid position 220 by the 20S proteasome (Sorokin et al. 2005). We showed that this C-terminal cleavage product P 220-317: (i) is translocated to cell nucleus most likely via the bipartite NLS 276-292; (ii) stimulates the MMP-2 promotor in nucleus, as was shown for full-length YB-1; (iii) exerts autoinhibitory effects on full-length YB-1 protein. These data suggest that YB-1 cleavage results in novel protein functions. Furthermore, we showed that YB-1 contains a Cytoplasmic Retention Site (CRS) in the region between the amino acids 52-101. No Nuclear Export Sequence (NES) could be identified. Next we examined the YB-1 localisation after different stimuli. Only in the tumor HeLa cells and only the full-length YB-1 localized to the nucleus after stimulation with thrombin, deferroxamin, aldosterone and angiotensin II.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2008
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Kuhl, Vanessa Alice
- Contributors dc:contributor
-
- Mertens, Peter René
Subjects
dc:subject × 12Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger