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Rhomboid proteases of the chloroplast and cyanobacterium

Rhomboid proteases of the chloroplast and cyanobacterium

Thompson, Elinor ORCID: 0000-0002-6434-9290 and Ibrahim, Iskander (2016) Rhomboid proteases of the chloroplast and cyanobacterium. In: 3rd International Conference on Plant Proteases: Plant Proteases: from roles in life and death to understanding regulation and action., 10-12 April 2016, University of Oxford, Oxford, UK.

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The ‘rhomboid’ proteases are conserved across all kingdoms, their characteristic transmembrane structure typified by the Escherichia coli prototype GlpG. Ironically, the bacterial rhomboids are least well characterised, but various eukaryotic roles have been reported. Rhomboids’ membrane locations are ideal for intracellular or extra-organellar signalling in regulatory and developmental pathways: Drosophila Rhomboid-1 cleaves tethered epidermal growth factor (EGF) ligands to activate EGF signalling; several mitochondrial rhomboids affect biology internal and external to the organelle via proteolysis of apoptotic-pathway intermediates; and an Arabidopsis rhomboid may activate retrograde signalling by a mitochondrial membrane-bound transcription factor. We visualised another organellar rhomboid in Arabidopsis, RBL10, on the chloroplast periphery, loss of which affected photosynthetic parameters and floral morphology. Rhomboids have been neglected in the chloroplast model, photosynthetic cyanobacteria. We investigated a Synechocystis representative, finding that photosynthetic parameters were unaltered by insertional inactivation of the rhomboid gene until mixotrophic conditions, when the rhomboid was required to reduce photosynthesis, a mechanism cyanobacteria use to conserve energy, reducing uptake of carbon dioxide when glucose is available. Transcription of the rhomboid gene was differentially regulated in a range of abiotic stress conditions and, notably, transcription levels were linked with induction of several genes that regulate high-affinity CO2 import.

Item Type: Conference or Conference Paper (Poster)
Uncontrolled Keywords: FtsH, rhomboid, protease, chloroplast, cyanobacterium, CCM
Faculty / School / Research Centre / Research Group: Faculty of Engineering & Science
Faculty of Education, Health & Human Sciences > School of Human Sciences (HUM)
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Last Modified: 09 Oct 2021 04:45

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