Sequence Elements in Both Subunits of the DNA Fragmentation Factor Are Essential for Its Nuclear Transport
| Autor: | Werner Albig, Joerg Kahle, Sonja Neimanis, Detlef Doenecke |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
alpha Karyopherins
Cytoplasm Protein subunit Nuclear Localization Signals Active Transport Cell Nucleus Apoptosis Importin Models Biological Biochemistry 03 medical and health sciences medicine Humans Poly-ADP-Ribose Binding Proteins Molecular Biology 030304 developmental biology Cell Nucleus 0303 health sciences Deoxyribonucleases biology 030302 biochemistry & molecular biology Cell Biology beta Karyopherins Molecular biology Protein Structure Tertiary Cell biology medicine.anatomical_structure Multiprotein Complexes Chaperone (protein) biology.protein DNA fragmentation Nuclear transport Apoptosis Regulatory Proteins Nucleus Nuclear localization sequence HeLa Cells Protein Binding |
| Zdroj: | Journal of Biological Chemistry. 282:35821-35830 |
| ISSN: | 0021-9258 |
| Popis: | DNA cleavage is a biochemical hallmark of apoptosis. In humans, apoptotic DNA cleavage is executed by DNA fragmentation factor (DFF) 40. In proliferating cells DFF40 is expressed in the presence of its chaperone and inhibitor DFF45, which results in the formation of the DFF complex. Here, we present a systematic analysis of the nuclear import of the DFF complex. Our in vitro experiments demonstrate that the importin alpha/beta-heterodimer mediates the translocation of the DFF complex from the cytoplasm to the nucleus. Both DFF subunits interact directly with the importin alpha/beta-heterodimer. However, importin alpha/beta binds more tightly to the DFF complex compared with the individual subunits. Additionally, the isolated C-terminal regions of both DFF subunits together bind importin alpha/beta more strongly than the individual C termini. Our results from in vivo studies reveal that the C-terminal regions of both DFF subunits harbor nuclear localization signals. Furthermore, nuclear import of the DFF complex requires the C-terminal regions of both subunits. In more detail, one basic cluster in the C-terminal region of each subunit, DFF40 (RLKRK) and DFF45 (KRAR), is essential for nuclear accumulation of the DFF complex. Based on these findings two alternative models for the interaction of importin alpha/beta with the DFF complex are presented. |
| Databáze: | OpenAIRE |
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