Identifizierung und Kartierung von nukleären Import- und Exportsignalmotiven innerhalb des Y-box-bindenden Proteins-1 (YB-1)

Y-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.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2008

Author dc:creator

• Kuhl, Vanessa Alice

Contributors dc:contributor

• Mertens, Peter René

• info:eu-repo/classification/ddc/610
• Transkription <Genetik>
• Zellkern
• Cytoplasma
• Transkriptionsfaktor
• Intrazellulärer Transport
• Medizin
• YB-1
• Deletionskonstrukt
• NLS
• NES
• deletion construct

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113009%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50463