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- García-Lorenzo, Maribel, et al.
(author)
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Degradation of the main Photosystem II light-harvesting complex
- 2005
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In: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-905X .- 1474-9092. ; 4, s. 1065-1071
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Journal article (peer-reviewed)abstract
- Many factors trigger the degradation of proteins, including changes in environmental conditions, genetic mutations, and limitations in the availability of cofactors. Despite the importance for viability, still very little is known about protein degradation and its regulation. The degradation of the most abundant membrane protein on Earth, the light-harvesting complex of Photosystem II (LHC II), is highly regulated under different environmental conditions, e.g. light stress, to prevent photochemical damage of the reaction center. However, despite major effort to identify the protease/proteases involved in the degradation of the apoproteins of LHC II the molecular details of this important process remain obscure. LHC II belongs to the family of chlorophyll a/b binding proteins (CAB proteins) and is located in the thylakoid membrane of the plant chloroplast. The results of biochemical experiments to isolate and characterize the protease degrading LHC II are summarized here and compared to our own recent finding indicating that a metalloprotease of the FtsH family is involved in this process.
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| 2. |
- Zelisko, Agnieszka, et al.
(author)
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AtFtsH6 is involved in the degradation of the light-harvesting complex II during high-light acclimation and senescence
- 2005
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 102:39, s. 13699-704
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Journal article (peer-reviewed)abstract
- Degradation of the most abundant membrane protein on earth, the light-harvesting complex of Photosystem II (LHC II), is highly regulated under various environmental conditions, e.g., light stress, to prevent photochemical damage to the reaction center. We identified the LHC II degrading protease in Arabidopsis thaliana as a Zn2+-dependent metalloprotease, activated by the removal of unknown extrinsic factors, similar to the proteolytic activity directed against Lhcb3 in barley. By using a reversed genetic approach, the chloroplast-targeted protease FtsH6 was identified as being responsible for the degradation. T-DNA KO A. thaliana mutants, lacking ftsH6, were unable to degrade either Lhcb3 during dark-induced senescence or Lhcb1 and Lhcb3 during highlight acclimation. The A. thaliana ftsH6 gene has a clear orthologue in the genome of Populus trichocarpa. It is likely that FtsH6 is a general LHC II protease and that FtsH6-dependent LHC II proteolysis is a feature of all higher plants.
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