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- Schneider, A., et al.
(författare)
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The Evolutionarily Conserved Protein PHOTOSYNTHESIS AFFECTED MUTANT71 Is Required for Efficient Manganese Uptake at the Thylakoid Membrane in Arabidopsis
- 2016
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Ingår i: Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 28:4, s. 892-910
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Tidskriftsartikel (refereegranskat)abstract
- In plants, algae, and cyanobacteria, photosystem II (PSII) catalyzes the light-driven oxidation of water. The oxygen-evolving complex of PSII is a Mn4CaO5 cluster embedded in a well-defined protein environment in the thylakoid membrane. However, transport of manganese and calcium into the thylakoid lumen remains poorly understood. Here, we show that Arabidopsis thaliana PHOTOSYNTHESIS AFFECTED MUTANT71 (PAM71) is an integral thylakoid membrane protein involved in Mn2+ and Ca2+ homeostasis in chloroplasts. This protein is required for normal operation of the oxygen-evolving complex (as evidenced by oxygen evolution rates) and for manganese incorporation. Manganese binding to PSII was severely reduced in pam71 thylakoids, particularly in PSII supercomplexes. In cation partitioning assays with intact chloroplasts, Mn2+ and Ca2+ ions were differently sequestered in pam71, with Ca2+ enriched in pam71 thylakoids relative to the wild type. The changes in Ca2+ homeostasis were accompanied by an increased contribution of the transmembrane electrical potential to the proton motive force across the thylakoid membrane. PSII activity in pam71 plants and the corresponding Chlamydomonas reinhardtii mutant cgld1 was restored by supplementation with Mn2+, but not Ca2+. Furthermore, PAM71 suppressed the Mn2+-sensitive phenotype of the yeast mutant Delta pmr1. Therefore, PAM71 presumably functions in Mn2+ uptake into thylakoids to ensure optimal PSII performance.
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| 2. |
- Mönnich, M., et al.
(författare)
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CEP128 Localizes to the Subdistal Appendages of the Mother Centriole and Regulates TGF-β/BMP Signaling at the Primary Cilium
- 2018
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Ingår i: Cell Reports. - : Elsevier. - 2211-1247. ; 22:10, s. 2601-2614
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Tidskriftsartikel (refereegranskat)abstract
- The centrosome is the main microtubule-organizing center in animal cells and comprises a mother and daughter centriole surrounded by pericentriolar material. During formation of primary cilia, the mother centriole transforms into a basal body that templates the ciliary axoneme. Ciliogenesis depends on mother centriole-specific distal appendages, whereas the role of subdistal appendages in ciliary function is unclear. Here, we identify CEP128 as a centriole subdistal appendage protein required for regulating ciliary signaling. Loss of CEP128 did not grossly affect centrosomal or ciliary structure but caused impaired transforming growth factor-β/bone morphogenetic protein (TGF-β/BMP) signaling in zebrafish and at the primary cilium in cultured mammalian cells. This phenotype is likely the result of defective vesicle trafficking at the cilium as ciliary localization of RAB11 was impaired upon loss of CEP128, and quantitative phosphoproteomics revealed that CEP128 loss affects TGF-β1-induced phosphorylation of multiple proteins that regulate cilium-associated vesicle trafficking. Mönnich et al. show that CEP128 localizes to the subdistal appendages of the mother centriole and basal body of the primary cilium. CEP128 regulates vesicular trafficking and targeting of RAB11 to the primary cilium. CEP128 loss leads to impaired TGF-β/BMP signaling, which, in zebrafish, is associated with defective organ development.
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