Investigation of IRQ domain containing proteins in Arabidopsis thaliana

The endomembrane system in eukaryotic cells plays a vital role in the movement of membranes and substances around the cell in response to abiotic and biotic stimuli. Recent work on an actin binding protein, NETWORKED4B (NET4B), revealed that this vacuolar localised protein (Deeks et al. 2012) contai...

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Main Author: Pridgeon, Greg Liam
Published: Durham University 2017
Online Access:https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738583
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spelling ndltd-bl.uk-oai-ethos.bl.uk-7385832019-01-08T03:35:43ZInvestigation of IRQ domain containing proteins in Arabidopsis thalianaPridgeon, Greg Liam2017The endomembrane system in eukaryotic cells plays a vital role in the movement of membranes and substances around the cell in response to abiotic and biotic stimuli. Recent work on an actin binding protein, NETWORKED4B (NET4B), revealed that this vacuolar localised protein (Deeks et al. 2012) contains a domain termed the IRQ domain responsible for interacting with particular regulatory proteins of the endomembrane system. Bioinformatic analysis revealed that this IRQ domain was present in six novel proteins not containing the characteristic NET Actin Binding (NAB) domain. These proteins were termed the IRQ proteins (IRQ1-6). Work outlined in this thesis explores the evolution and localisation of expression of these proteins but in particular looks at IRQ4. Phylogenetic analysis revealed that the IRQ proteins represent a eudicot specific group of proteins and that they evolved from the NET proteins. The IRQ proteins can be subdivided based on sequence similarity into three groups: IRQ1 and IRQ6, IRQ2 and IRQ3, IRQ4 and IRQ5. Using promoter GUS lines for IRQ1 and IRQ6 revealed that these proteins may be involved in the initiation or regulation of lateral root growth. IRQ4 was expressed most strongly in the root. Subcellular localisation analysis using promIRQ4::IRQ4-GFP and live cell imaging showed that IRQ4 localises to the prevacuolar compartment (PVC)/multivesicular body (MVB). Immunogold labelling using an IRQ4 specific antibody revealed an additional localisation to autophagasomes. This project investigates a group of novel eudicot specific proteins and shows that IRQ4 may be involved in key endomembrane pathways in plants.Durham Universityhttps://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738583http://etheses.dur.ac.uk/12535/Electronic Thesis or Dissertation
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description The endomembrane system in eukaryotic cells plays a vital role in the movement of membranes and substances around the cell in response to abiotic and biotic stimuli. Recent work on an actin binding protein, NETWORKED4B (NET4B), revealed that this vacuolar localised protein (Deeks et al. 2012) contains a domain termed the IRQ domain responsible for interacting with particular regulatory proteins of the endomembrane system. Bioinformatic analysis revealed that this IRQ domain was present in six novel proteins not containing the characteristic NET Actin Binding (NAB) domain. These proteins were termed the IRQ proteins (IRQ1-6). Work outlined in this thesis explores the evolution and localisation of expression of these proteins but in particular looks at IRQ4. Phylogenetic analysis revealed that the IRQ proteins represent a eudicot specific group of proteins and that they evolved from the NET proteins. The IRQ proteins can be subdivided based on sequence similarity into three groups: IRQ1 and IRQ6, IRQ2 and IRQ3, IRQ4 and IRQ5. Using promoter GUS lines for IRQ1 and IRQ6 revealed that these proteins may be involved in the initiation or regulation of lateral root growth. IRQ4 was expressed most strongly in the root. Subcellular localisation analysis using promIRQ4::IRQ4-GFP and live cell imaging showed that IRQ4 localises to the prevacuolar compartment (PVC)/multivesicular body (MVB). Immunogold labelling using an IRQ4 specific antibody revealed an additional localisation to autophagasomes. This project investigates a group of novel eudicot specific proteins and shows that IRQ4 may be involved in key endomembrane pathways in plants.
author Pridgeon, Greg Liam
spellingShingle Pridgeon, Greg Liam
Investigation of IRQ domain containing proteins in Arabidopsis thaliana
author_facet Pridgeon, Greg Liam
author_sort Pridgeon, Greg Liam
title Investigation of IRQ domain containing proteins in Arabidopsis thaliana
title_short Investigation of IRQ domain containing proteins in Arabidopsis thaliana
title_full Investigation of IRQ domain containing proteins in Arabidopsis thaliana
title_fullStr Investigation of IRQ domain containing proteins in Arabidopsis thaliana
title_full_unstemmed Investigation of IRQ domain containing proteins in Arabidopsis thaliana
title_sort investigation of irq domain containing proteins in arabidopsis thaliana
publisher Durham University
publishDate 2017
url https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738583
work_keys_str_mv AT pridgeongregliam investigationofirqdomaincontainingproteinsinarabidopsisthaliana
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