| 1. |
- Aigner, Harald, 1973-, et al.
(författare)
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FtsH11 protease is required for Arabidopsis thaliana to adapt to gtowth in continuous light
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Continuous light can increase greenhouse food production; however, some of the most important greenhouse horticulture crops are not able to adapt to long photoperiods. Here, we provide evidence that knock-out of the FtsH11 protease causes molecular differences that prevent Arabidopsis thaliana to adapt to prolonged photoperiods. Previously this protease had been shown to be critical for thermotolerance (Chen et al. 2006). We demonstrate that knock-out mutants deficient of FtsH11 develop chlorosis when shifted to continuous light. When grown under normal growth conditions and short days, ftsh11 displayed changes in protein amount of chloroplast proteins involved in the photosynthetic light reaction and the Calvin cycle as well as of the FtsH12 protease. The proteomic changes are accompanied by reduced non-photochemical quenching and faster state transition. A shift to continuous light further enhanced these effects and induced morphological changes of the chloroplast and chlorosis. No changes in the mitochondrial proteome were observed between wild type and ftsh11.
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| 2. |
- Cheregi, Otilia, et al.
(författare)
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Insights into the Cyanobacterial Deg/HtrA Proteases
- 2016
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Ingår i: Frontiers in Plant Science. - : Frontiers Media S.A. - 1664-462X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Proteins are the main machinery for all living processes in a cell; they provide structural elements, regulate biochemical reactions as enzymes, and are the interface to the outside as receptors and transporters. Like any other machinery proteins have to be assembled correctly and need maintenance after damage, e.g., caused by changes in environmental conditions, genetic mutations, and limitations in the availability of cofactors. Proteases and chaperones help in repair, assembly, and folding of damaged and misfolded protein complexes cost-effective, with low energy investment compared with neo-synthesis. Despite their importance for viability, the specific biological role of most proteases in vivo is largely unknown. Deg/HtrA proteases, a family of serinetype ATP-independent proteases, have been shown in higher plants to be involved in the degradation of the Photosystem II reaction center protein D1. The objective of this review is to highlight the structure and function of their cyanobacterial orthologs. Homology modeling was used to find specific features of the SynDeg/HtrA proteases of Synechocystis sp. PCC 6803. Based on the available data concerning their location and their physiological substrates we conclude that these Deg proteases not only have important housekeeping and chaperone functions within the cell, but also are needed for remodeling the cell exterior.
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| 3. |
- Hall, Michael, et al.
(författare)
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The HhoA protease from Synechocystis sp. PCC 6803 : novel insights into structure and activity regulation
- 2017
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Ingår i: Journal of Structural Biology. - : Elsevier. - 1047-8477 .- 1095-8657. ; 198:3, s. 147-153
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Tidskriftsartikel (refereegranskat)abstract
- Proteases play a vital role in the removal of proteins, which become damaged due to temperature or oxidative stress. Important to this process in the cyanobacterium Synechocystis sp. PCC6803 is the family of Deg/HtrA proteases; HhoA (sll1679), HhoB (sll1427) and HtrA (slr1204). While previous studies have elucidated the structures of Deg/HtrA proteases from Escherichia coli and from the chloroplast of the higher plant Arabidopsis thaliana, no structural data have been available for any Deg/HtrA protease from cyanobacteria, the evolutionary ancestor of the chloroplast. To gain a deeper insight into the molecular mechanisms and regulation of these proteins we have solved the structure of the Synechocystis HhoA protease in complex with a co-purified peptide by X-ray crystallography. HhoA assembles into stable trimers, mediated by its protease domain and further into a cage-like hexamer by a novel interaction between the PDZ domains of opposing trimers. Each PDZ domain contains two loops for PDZ-PDZ formation: interaction clamp one and two (IC1, IC2). IC1 interacts with IC2 on the opposing PDZ domain and vice versa. Our structure shows a peptide bound to a conserved groove on the PDZ domain and the properties of this pocket suggest that it binds substrate proteins as well as the neo C-termini of cleaved substrates. In agreement with previous studies showing the proteolytic activity of HhoA to be activated by Ca2+ or Mg2+, binding of divalent metal ions to the central channel of the trimer by the L1 activation loop was observed.
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| 4. |
- Mielke, Kati, 1981-, et al.
(författare)
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Abundance of metalloprotease FtsH12 modulates chloroplast development in Arabidopsis thaliana
- 2021
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 72:9, s. 3455-3473
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Tidskriftsartikel (refereegranskat)abstract
- The ATP-dependent metalloprotease FtsH12 (filamentation temperature sensitive protein H 12) has been suggested to participate in a heteromeric motor complex, driving protein translocation into the chloroplast. FtsH12 was immuno-detected in proplastids, seedlings, leaves, and roots. Expression of Myc-tagged FtsH12 under its native promotor allowed identification of FtsHi1, 2, 4, and 5, and plastidic NAD-malate dehydrogenase, five of the six interaction partners in the suggested import motor complex. Arabidopsis thaliana mutant seedlings with reduced FTSH12 abundance exhibited pale cotyledons and small, deformed chloroplasts with altered thylakoid structure. Mature plants retained these chloroplast defects, resulting in slightly variegated leaves and lower chlorophyll content. Label-free proteomics revealed strong changes in the proteome composition of FTSH12 knock-down seedlings, reflecting impaired plastid development. The composition of the translocon on the inner chloroplast membrane (TIC) protein import complex was altered, with coordinated reduction of the FtsH12-FtsHi complex subunits and accumulation of the 1 MDa TIC complex subunits TIC56, TIC214 and TIC22-III. FTSH12 overexpressor lines showed no obvious phenotype, but still displayed distinct differences in their proteome. N-terminome analyses further demonstrated normal proteolytic maturation of plastid-imported proteins irrespective of FTSH12 abundance. Together, our data suggest that FtsH12 has highest impact during seedling development; its abundance alters the plastid import machinery and impairs chloroplast development.
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| 5. |
- Mishra, Laxmi S., et al.
(författare)
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Reduced expression of the proteolytically inactive FtsH members has impacts on the Darwinian fitness of Arabidopsis thaliana
- 2019
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 70:7, s. 2173-2184
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Tidskriftsartikel (refereegranskat)abstract
- FtsH (filamentation-temperature-sensitive protein H) proteases are a family of membrane-bound enzymes present in eubacteria, animals, and plants. Besides the 12 genes encoding proteolytically active members of the FtsH family in the genome of Arabidopsis, there are five genes coding for members that are assumed to be proteolytically inactive due to mutations in the protease domain; these are termed FtsHi (i for inactive). Despite their lack of proteolytic activity, these FtsHi members seem to be important for chloroplast and plant development as four out of five homozygous knockout-mutants of FtsHis are embryo-lethal. Here, we analysed the Darwinian fitness of weak homozygous (ftshi1,3,4) and heterozygous (ftshi/FTSHi2,4,5) mutants. We compared the growth and development of these mutants to their respective wild-type Arabidopsis plants under controlled laboratory conditions and in the field, and we also evaluated the photosynthetic efficiency by pulse-amplitude modulation fluorescence. Homologous genotypes were subjected to various stress conditions in a greenhouse and gene co-expression as well as phylogenetic analyses were performed. Analysis of the gene-expression network of the five FTSHi genes indicated common clusters with genes encoding FtsH12, OTP51, and methylase. Phylogenetic analyses pointed to a common evolution (and common disappearance in grasses and gymnosperms) of FtsH12 and multiple presumably proteolytically inactive FtsHi enzymes. Our data show that the FtsHi enzymes are highly important during the seedling stage and for Darwinian fitness analyses in semi-natural conditions.
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| 6. |
- Wagner, Leona, et al.
(författare)
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Neuropeptide Y (NPY) in cerebrospinal fluid from patients with Huntington's Disease : increased NPY levels and differential degradation of the NPY1-30 fragment
- 2016
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 137:5, s. 820-837
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Tidskriftsartikel (refereegranskat)abstract
- Huntington's disease (HD) is an inherited and fatal polyglutamine neurodegenerative disorder caused by an expansion of the CAG triplet repeat coding region within the HD gene. Progressive dysfunction and loss of striatal GABAergic medium spiny neurons (MSNs) may account for some of the characteristic symptoms in HD patients. Interestingly, in HD, MSNs expressing neuropeptide Y (NPY) are spared and their numbers is even up-regulated in HD patients. In line with this, we report here on increased immuno-linked NPY (IL-NPY) levels in human cerebrospinal fluid (hCSF) from HD patients. As this antibody-based detection of NPY may provide false positive differences due to the antibody-based detections of only fragments of NPY, the initial finding was validated by investigating the proteolytic stability of NPY in hCSF using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and selective inhibitors. A comparison between resulting NPY-fragments and detailed epitope analysis verified significant differences of IL-NPY1-36/3-36 and NPY1-30 levels between HD patients and control subjects. Ex vivo degradomics analysis demonstrated that NPY is initially degraded to NPY1-30 by cathepsin D (CTSD) in both HD patients and control subjects. Yet, NPY1-30 is then further differentially hydrolyzed by thimet oligopeptidase (TOP) in HD patients and by neprilysin (NEP) in control subjects. Furthermore, altered hCSF TOP-inhibitor Dynorphin A1-13 (Dyn-A1-13 ) and TOP-substrate Dyn-A1-8 levels indicate an impaired Dyn-A-TOP network in HD patients. Thus, we conclude that elevated IL-NPY-levels in conjunction with TOP- / NEP-activity/protein as well as Dyn-A1-13 -protein levels may serve as a potential biomarker in human CSF of HD. This article is protected by copyright. All rights reserved.
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| 7. |
- Wagner, Leona, et al.
(författare)
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Proteolytic degradation of neuropeptide Y (NPY) from head to toe: Identification of novel NPY-cleaving peptidases and potential drug interactions in CNS and Periphery.
- 2015
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 135:5, s. 1019-1037
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Tidskriftsartikel (refereegranskat)abstract
- The bioactivity of neuropeptide Y (NPY) is either N-terminally modulated with respect to receptor-selectivity by dipeptidyl-peptidase 4 (DP4)-like enzymes or proteolytic degraded by neprilysin or meprins, thereby abrogating signal transduction. However, neither the subcellular nor the compartmental differentiation of these regulatory mechanisms is fully understood. Using mass spectrometry, selective inhibitors and histochemistry, studies across various cell types, body fluids and tissues revealed that most frequently DP4-like enzymes, aminopeptidases P (AmpP), secreted meprin-A (Mep-A) and cathepsin D (CTSD) rapidly hydrolyze NPY, depending on the cell type and tissue under study. Novel degradation of NPY by cathepsins B, D, L, G, S and tissue kallikrein could also be identified. Expression of DP4, CTSD, and Mep-A at the median eminence indicates that the bioactivity of NPY is regulated by peptidases at the interphase between the periphery and the CNS. Detailed ex vivo studies on human sera and CSF samples recognized CTSD as the major NPY-cleaving enzyme in the CSF, whereas an additional C-terminal truncation by angiotensin-converting enzyme (ACE) could be detected in serum. The latter finding hints to potential drug interaction between antidiabetic DP4 inhibitors and anti-hypertensive ACE inhibitors, while it ablates suspected hypertensive side-effects of only antidiabetic DP4-inhibitors application. This article is protected by copyright. All rights reserved.
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| 8. |
- Wagner, Raik, et al.
(författare)
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Deletion of FtsH11 protease has impact on chloroplast structure and function in Arabidopsis thaliana when grown under continuous light
- 2016
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Ingår i: Plant Cell and Environment. - : Wiley. - 0140-7791 .- 1365-3040. ; 39:11, s. 2530-2544
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Tidskriftsartikel (refereegranskat)abstract
- The membrane-integrated metalloprotease FtsH11 of Arabidopsis thaliana is proposed to be dual-targeted to mitochondria and chloroplasts. A bleached phenotype was observed in ftsh11 grown at long days or continuous light, pointing to disturbances in the chloroplast. Within the chloroplast, FtsH11 was found to be located exclusively in the envelope. Two chloroplast-located proteins of unknown function (Tic22-like protein and YGGT-A) showed significantly higher abundance in envelope membranes and intact chloroplasts of ftsh11 and therefore qualify as potential substrates for the FtsH11 protease. No proteomic changes were observed in the mitochondria of 6-week-old ftsh11 compared with wild type, and FtsH11 was not immunodetected in these organelles. The abundance of plastidic proteins, especially of photosynthetic proteins, was altered even during standard growth conditions in total leaves of ftsh11. At continuous light, the amount of photosystem I decreased relative to photosystem II, accompanied by a drastic change of the chloroplast morphology and a drop of non-photochemical quenching. FtsH11 is crucial for chloroplast structure and function during growth in prolonged photoperiod. The membrane-integrated metalloprotease FtsH11 of Arabidopsis thaliana was found to be located exclusively in the chloroplast envelope and to be crucial for chloroplast structure and function during growth in prolonged photoperiod. Two chloroplast-located proteins of unknown function (Tic22-like protein and YGGT-A) showed significantly higher abundance in envelope membranes and intact chloroplasts of ftsH11 and therefore qualify as potential substrates for the FtsH11 protease.
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| 9. |
- Wagner, Raik, 1976-, et al.
(författare)
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Fitness analyses of Arabidopsis thaliana mutants depleted of FtsH metalloproteases and characterization of three FtsH6 deletion mutants exposed to high light stress, senescence and chilling
- 2011
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 191:2, s. 449-458
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Tidskriftsartikel (refereegranskat)abstract
- Darwinian fitness analyses were performed, comparing single ftsh mutants with wild-type Arabidopsis thaliana plants grown under controlled laboratory conditions and in the field, by measuring plant size, survival rate, and silique and seed production. Additionally, three genotypes of ΔFtsH6 were analysed, under controlled growth conditions, with respect to both their ability to degrade the light-harvesting complex of photosystem II during senescence and light acclimation. In the field, substantial increases in variegation and reductions in growth were observed in the ΔFtsH2, ΔFtsH5 and ΔFtsH10 mutants; FtsH2 seemed particularly important for plant survival. Despite being grown in relatively cold weather, the ΔFtsH11 mutant displayed strong phenotypic deviations from wild type. Both ΔFtsH10 and ΔFtsH3 mutants exhibited less severe phenotypic changes, but were different from wild-type plants when placed in the field as young plants. When older ΔFtsH3 or ΔFtsH10 mutants were placed outdoors, no phenotypic differences from wild type were observed. Three genotypes of ΔFtsH6 displayed no phenotypic deviations from wild-type plants. Under controlled growth conditions, during senescence and light acclimation, no differences in the amount of chlorophyll or Photosystem II light-harvesting complex b3 (Lhcb3) were detected in ΔFtsH6 mutants compared with the wild type. Therefore, FtsH6 seems to be unimportant for LHCII degradation in vivo.
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| 10. |
- Wagner, Raik, 1976-, et al.
(författare)
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FtsH proteases located in the plant chloroplast
- 2012
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Ingår i: Physiologia Plantarum. - Oxford : Wiley-Blackwell. - 0031-9317 .- 1399-3054. ; 145:1, s. 203-214
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Tidskriftsartikel (refereegranskat)abstract
- FtsHs are a well-characterized family of membrane bound proteases containing an AAA (ATPase associated with various cellular activities) and a Zn2+ metalloprotease domain. FtsH proteases are found in eubacteria, animals and plants, and are known to have a crucial role in housekeeping proteolysis of membrane proteins. In Arabidopsis thaliana 12 FtsH family members are present (FtsH 1–12) and their subcellular localization is restricted to mitochondria and chloroplasts. In addition, five genes coding for proteins homologous to FtsH (FtsHi 1–5) have been detected in the genome, lacking the conserved zinc-binding motif HEXXH, which presumably renders them inactive for proteolysis. These inactive FtsHs as well as nine of the active FtsHs are thought to be localized in the chloroplast. In this minireview we shortly summarize the recent findings on plastidic FtsH proteases in text and figures. We will mainly focus on FtsH 1, 2, 5 and 8, localized in the thylakoid membrane and known for their importance in photosynthesis.
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