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- Hansson, Markus, et al.
(författare)
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Targeting proteins to secretory lysosomes of natural killer cells as a principle for immunoregulation.
- 2003
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Ingår i: Molecular Immunology. - 1872-9142. ; 40:6, s. 363-372
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Tidskriftsartikel (refereegranskat)abstract
- Secretory lysosomes of natural killer (NK) cells combine storage, regulated secretion and lysosomal activity. We asked whether one could target exogenous proteins to the secretory lysosomes of NK-cells for final delivery into a tumor site upon degranulation. cDNAs for both soluble and transmembrane (tm) proteins were expressed in the human YT-Indy NK-cell line. Targeting of a soluble TNF receptor (sTNFR1) was achieved by expressing a cDNA construct with a transmembrane sequence to facilitate ER-export and by incorporating a cytosolic sorting signal (Y) from CD63 to overcome constitutive secretion. The resulting sTNFR1-tm-Y was targeted to secretory lysosomes as confirmed by results from biosynthetic radiolabeling in combination with subcellular fractionation, immunoelectron microscopy, and immunofluorescence microscopy. A soluble sTNFR1 form was generated in the secretory lysosome by endogenous proteolytic activity. Expression of exogenous normally secretory non-membrane proteins, such as alpha1-microglobulin (alpha1-m) and alpha1-antitrypsin (alpha1-at) resulted mostly in constitutive secretion although a small amount of alpha1-microglobulin was targeted to secretory lysosomes. Our results suggest a potential for delivery of pharmacologically active agents into tumor sites by use of the NK-cell secretory lysosome as a carrier. (C) 2003 Elsevier Ltd. All rights reserved.
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| 2. |
- Rondin Lindberg, Sofia, et al.
(författare)
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Interactions between the leukaemia-associated ETO homologues of nuclear repressor proteins.
- 2003
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Ingår i: European Journal of Haematology. - : Wiley. - 1600-0609 .- 0902-4441. ; 71:6, s. 439-447
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Tidskriftsartikel (refereegranskat)abstract
- The eight-twenty-one (ETO) homologues, represented by ETO, myeloid transforming gene-related protein 1 (MTGR1) and myeloid transforming gene chromosome 16 (MTG16), are nuclear repressor proteins. ETO is part of the fusion protein acute myeloid leukaemia (AML)1-ETO, resulting from the translocation (8;21). Similarly, MTG16 is disrupted to become part of AML1/MTG16 in t(16;21). The aberrant expression of these chimeras could affect interplay between ETO homologues and contribute to the leukaemogenic process. We investigated possible interactions between the ETO homologues. Ectopic co-expression in COS-cells resulted in heterodimerisation of the various ETO homologues suggesting that they may co-operate. Similarly, the chimeric oncoprotein AML1-ETO interacted with both MTGR1 and MTG16. However, results from cell lines endogenously expressing more than one ETO homologue did not demonstrate co-precipitation. Results from IP-Western and size determination by gel filtration of deletion mutants expressed in COS-cells, indicated an important role of the HHR domain for oligomerisation. A role was also suggested for the Nervy domain in the homologue interactions. Our results suggest that ETO homologues can interact with each other as well as with AML1-ETO, although it is unclear as to what extent these interactions occur in vivo.
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