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| 2. |
- Chen, YZ, et al.
(författare)
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Structure and function analysis of the C. elegans aminophospholipid translocase TAT-1
- 2019
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Ingår i: Journal of cell science. - : The Company of Biologists. - 1477-9137 .- 0021-9533. ; 132:5
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Tidskriftsartikel (refereegranskat)abstract
- The C. elegans aminophospholipid translocase TAT–1 maintains phosphatidylserine (PS) asymmetry in the plasma membrane and regulates endocytic transport. Despite these important functions, the structure-function relationship of this protein is poorly understood. Taking advantage of the tat-1 mutations identified by the C. elegans million mutation project, we investigated the effects of 16 single amino-acid substitutions on the two functions of the TAT–1 protein. Two substitutions that alter a highly conserved PISL motif in the fourth transmembrane domain and a highly conserved DKTGT phosphorylation motif, respectively, disrupt both functions of TAT-1, leading to a vesicular gut defect and ectopic PS exposure on cell surface, whereas most other substitutions across the TAT-1 protein, often predicted to be deleterious by bioinformatics programs, do not affect the functions of TAT-1. These results provide in vivo evidence for the importance of the PISL and DKTGT motifs in P4–type adenosine triphosphatases (ATPases) and improve our understanding of the structure-function relationship of TAT-1. Our study also provides an example of how the C. elegans million mutation project helps decipher the structure, functions, and mechanisms of action of important genes.
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| 3. |
- Gallud, A, et al.
(författare)
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Cationic gold nanoparticles elicit mitochondrial dysfunction: a multi-omics study
- 2019
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1, s. 4366-
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Tidskriftsartikel (refereegranskat)abstract
- Systems biology is increasingly being applied in nanosafety research for observing and predicting the biological perturbations inflicted by exposure to nanoparticles (NPs). In the present study, we used a combined transcriptomics and proteomics approach to assess the responses of human monocytic cells to Au-NPs of two different sizes with three different surface functional groups, i.e., alkyl ammonium bromide, alkyl sodium carboxylate, or poly(ethylene glycol) (PEG)-terminated Au-NPs. Cytotoxicity screening using THP-1 cells revealed a pronounced cytotoxicity for the ammonium-terminated Au-NPs, while no cell death was seen after exposure to the carboxylated or PEG-modified Au-NPs. Moreover, Au-NR3+ NPs, but not the Au-COOH NPs, were found to trigger dose-dependent lethality in vivo in the model organism, Caenorhabditis elegans. RNA sequencing combined with mass spectrometry-based proteomics predicted that the ammonium-modified Au-NPs elicited mitochondrial dysfunction. The latter results were validated by using an array of assays to monitor mitochondrial function. Au-NR3+ NPs were localized in mitochondria of THP-1 cells. Moreover, the cationic Au-NPs triggered autophagy in macrophage-like RFP-GFP-LC3 reporter cells, and cell death was aggravated upon inhibition of autophagy. Taken together, these studies have disclosed mitochondria-dependent effects of cationic Au-NPs resulting in the rapid demise of the cells.
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| 6. |
- Kloditz, K, et al.
(författare)
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Three cell deaths and a funeral: macrophage clearance of cells undergoing distinct modes of cell death
- 2019
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Ingår i: Cell death discovery. - : Springer Science and Business Media LLC. - 2058-7716. ; 5, s. 65-
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Tidskriftsartikel (refereegranskat)abstract
- Macrophage clearance of apoptotic cells has been extensively investigated, but less is known regarding the clearance of cells dying by other forms of programmed cell death, e.g., necroptosis or ferroptosis. Here, we established a model of three different cell deaths using the same cell line and the occurrence of distinct cell death modalities was verified by using the specific inhibitors, zVAD-fmk, necrostatin-1, and ferrostatin-1, respectively. Cell death was characterized by using transmission electron microscopy (TEM), the gold standard for the demarcation of different cell death modalities. Moreover, using annexin V as a probe, we could detect surface exposure of phosphatidylserine (PS) in all three types of cell death, and this was confirmed by using specific anti-PS antibodies. We then co-cultured the cells with human monocyte-derived macrophages and found that cells dying by all three death modalities were engulfed by macrophages. Macrophage clearance of apoptotic cells was more efficient when compared to necroptotic and ferroptotic cells with multiple internalized target cells per macrophage, as shown by TEM. We propose that clearance of dying cells also should be taken into account in the classification of different cell death modalities.
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