Rafiq, Mehak, Traynor, David and Thompson, Elinor ORCID: 0000-0002-6434-9290 (2014) Investigating ‘rhomboid’ membrane proteases’ roles in development and signalling in Dictyostelium. In: Dicty 2014 Annual International Dictyostelium Conference, 3-7 Aug 2014, Potsdam, Germany.

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Abstract

The rhomboid family of intramembrane serine proteases is almost ubiquitous across all kingdoms of life. The enzymes are poorly conserved at sequence level but are similar in their structures and active-site motifs. They cleave disparate substrates, and it is the role of rhomboids across evolution that seems to be better conserved, since a membrane location means they are ideally placed for signalling and proteolytic activation events. Thus, we are investigating rhomboid function in the development and chemotaxis of Dictyostelium discoideum, the microbial, biomedical model organism that is capable of unicellular vegetative growth and multicellular development. A small group, including four apparently enzymatically active, rhomboids was identified in Dictyostelium. We found that development was unaltered following deletion of rhmC, whereas attempts to knock out the putative mitochondrial rhmD proved lethal. rhmA and rhmB null mutants give rise to changes in development, the lack of RhmA altering the response to chemoattractants and decreasing motility of the multicellular ‘slug’. rhmB null cells have lower viability, a smaller spore-sorus and a decreased response to folic acid stimulation. These results correspond with qRTPCR analysis, in which rhmA and rhmB transcript levels are highest during the multicellular growth phase. TEM intriguingly suggests a role in mitochondrion ultrastructure for RhmA, supported by bioinformatic interaction networks. These reveal Dictyostelium RhmA cotranscription with homologues of the Saccharomyces cerevisiae mitochondrial rhomboid’s substrates, which also regulate mitochondrial morphology.

Item Type:	Conference or Conference Paper (Paper)
Additional Information:	[1] This paper was presented at the Dicty 2014 Annual International Dictyostelium Conference held from 3-7 August 2014 in Potsdam, Germany. It was given by Mehak Rafiq on 4 August 2014, within the Development Session.
Uncontrolled Keywords:	rhomboid protease, mitochondrion, Dictyostelium
Subjects:	Q Science > QH Natural history > QH301 Biology
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science Faculty of Education, Health & Human Sciences > School of Human Sciences (HUM)
Related URLs:	Organisation
Last Modified:	09 Oct 2021 04:46
URI:	http://gala.gre.ac.uk/id/eprint/12261

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