{"id":{"repo_id":"cambridge","oai_identifier":"oai:www.repository.cam.ac.uk:1810/303943"},"canonical_url":"https://search.dev.ndltd.org/etd/cambridge/oai:www.repository.cam.ac.uk:1810/303943","repository":{"repo_id":"cambridge","name":"Cambridge University","base_url":"https://api.repository.cam.ac.uk/server/oai/request"},"display":{"title":"The Role of Arabidopsis thaliana Annexins 1, 2 and 4 in Extracellular ATP Signalling","abstract":"Extracellular ATP (eATP) is an important signalling molecule in animals but its importance is less understood in plants. Accumulation of eATP in plants occurs in response to biotic and abiotic stresses. eATP causes downstream responses such as increase in cytosolic free calcium ([Ca$^{2+}$]$_{cyt}$), reactive oxygen species (ROS), nitric oxide (NO) and phosphatidic acid (PA). The identification of $\\it{Arabidopsis}$ $\\it{thaliana}$ AtDORN1 (Does Not Respond to Nucleotides) as the first higher plant purinoreceptor has confirmed eATP in plant signalling systems. AtDORN1 is a plasma membrane receptor kinase that appears to command the eATP-induced transient increase in [Ca$^{2+}$]$_{cyt}$ and directs the translational response to wounding. The identity of the plasma membrane Ca$^{2+}$-permeable channels involved in eATP-induced [Ca$^{2+}$]$_{cyt}$ increases remain unknown. Patch clamp electrophysiology has shown that a plasma membrane Ca$^{2+}$ influx conductance lies downstream of the AtRBOHC NADPH oxidase in the response to eATP. As $\\it{Arabidopsis}$ $\\it{thaliana}$ ANNEXIN 1 (AtANN1) underpins ROS-activated plasma membrane Ca$^{2+}$ influx conductance, it has been considered here as operating downstream of AtDORN1 in the eATP-induced increase in [Ca$^{2+}$]$_{cyt}$. In this thesis, the role of AtANN1, AtANN2 and AtANN4 in eATP signalling was tested in $\\it{A.}$ $\\it{thaliana}$. Using (apo)aequorin, AtANN1 and ANNEXIN 2 (AtANN2) have been found to be involved in the root′s [Ca$^{2+}$]$_{cyt}$ response to both eATP and eADP whereas ANNEXIN 4 (AtANN4) might be acting as a negative regulator of AtANN1 (Chapters 3 and 4). Application of Gd$^{3+}$ as a plasma membrane Ca$^{2+}$ channel blocker indicated the possibility of the release of Ca$^{2+}$ from intracellular stores (Chapters 3 and 4). AtANN1 is confirmed to be downstream of the AtDORN1 receptor and also possibly downstream of AtRBOH NADPH Oxidase based on [Ca$^{2+}$]$_{cyt}$ measurement and ROS assays (Chapter 3). Loss${-}$of${-}$function mutants of AtANN1, AtANN2 and AtANN4 altered the eATP${-}$induced gene expression of $\\it{AtACS6}$ but not $\\it{AtWRKY40}$ demonstrating a possible link between eATP signalling and hormone responses in plants (Chapters 3 and 4). Unlike AtANN1 and AtANN4, fewer studies regarding the involvement of AtANN2 in salinity stress and biotic stress were reported. In Chapter 5, results suggest that AtANN2 might not be part of the components mediating salinity stress and biotic stress in plants.","abstract_html":"Extracellular ATP (eATP) is an important signalling molecule in animals but its importance is less understood in plants. Accumulation of eATP in plants occurs in response to biotic and abiotic stresses. eATP causes downstream responses such as increase in cytosolic free calcium ([Ca<span class=\"etd-inline-math\"><sup>2+</sup></span>]<span class=\"etd-inline-math\"><sub>cyt</sub></span>), reactive oxygen species (ROS), nitric oxide (NO) and phosphatidic acid (PA). The identification of $\\it{Arabidopsis}$ $\\it{thaliana}$ AtDORN1 (Does Not Respond to Nucleotides) as the first higher plant purinoreceptor has confirmed eATP in plant signalling systems. AtDORN1 is a plasma membrane receptor kinase that appears to command the eATP-induced transient increase in [Ca<span class=\"etd-inline-math\"><sup>2+</sup></span>]<span class=\"etd-inline-math\"><sub>cyt</sub></span> and directs the translational response to wounding. The identity of the plasma membrane Ca<span class=\"etd-inline-math\"><sup>2+</sup></span>-permeable channels involved in eATP-induced [Ca<span class=\"etd-inline-math\"><sup>2+</sup></span>]<span class=\"etd-inline-math\"><sub>cyt</sub></span> increases remain unknown. Patch clamp electrophysiology has shown that a plasma membrane Ca<span class=\"etd-inline-math\"><sup>2+</sup></span> influx conductance lies downstream of the AtRBOHC NADPH oxidase in the response to eATP. As $\\it{Arabidopsis}$ $\\it{thaliana}$ ANNEXIN 1 (AtANN1) underpins ROS-activated plasma membrane Ca<span class=\"etd-inline-math\"><sup>2+</sup></span> influx conductance, it has been considered here as operating downstream of AtDORN1 in the eATP-induced increase in [Ca<span class=\"etd-inline-math\"><sup>2+</sup></span>]<span class=\"etd-inline-math\"><sub>cyt</sub></span>. In this thesis, the role of AtANN1, AtANN2 and AtANN4 in eATP signalling was tested in $\\it{A.}$ $\\it{thaliana}$. Using (apo)aequorin, AtANN1 and ANNEXIN 2 (AtANN2) have been found to be involved in the root′s [Ca<span class=\"etd-inline-math\"><sup>2+</sup></span>]<span class=\"etd-inline-math\"><sub>cyt</sub></span> response to both eATP and eADP whereas ANNEXIN 4 (AtANN4) might be acting as a negative regulator of AtANN1 (Chapters 3 and 4). Application of Gd<span class=\"etd-inline-math\"><sup>3+</sup></span> as a plasma membrane Ca<span class=\"etd-inline-math\"><sup>2+</sup></span> channel blocker indicated the possibility of the release of Ca<span class=\"etd-inline-math\"><sup>2+</sup></span> from intracellular stores (Chapters 3 and 4). AtANN1 is confirmed to be downstream of the AtDORN1 receptor and also possibly downstream of AtRBOH NADPH Oxidase based on [Ca<span class=\"etd-inline-math\"><sup>2+</sup></span>]<span class=\"etd-inline-math\"><sub>cyt</sub></span> measurement and ROS assays (Chapter 3). Loss${-}$of${-}$function mutants of AtANN1, AtANN2 and AtANN4 altered the eATP${-}$induced gene expression of $\\it{AtACS6}$ but not $\\it{AtWRKY40}$ demonstrating a possible link between eATP signalling and hormone responses in plants (Chapters 3 and 4). Unlike AtANN1 and AtANN4, fewer studies regarding the involvement of AtANN2 in salinity stress and biotic stress were reported. In Chapter 5, results suggest that AtANN2 might not be part of the components mediating salinity stress and biotic stress in plants.","abstract_has_math":true,"creators":["Binti Mohammad Sidik, Amirah"],"institution":"University of Cambridge","degree_name":"Doctor of Philosophy (PhD)","degree_level":"Doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Davies, Julia"],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-03-03","date_published":"2020-03-03","updated_at":"2026-07-22T22:24:06Z","subjects":["extracellular ATP signalling","cytosolic free calcium ion","annexins","salinity stress","DORN1"],"languages":["en"],"rights":[],"rights_urls":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/f6624b7f-a23c-482b-bad1-39f21e24c48b/download","https://www.rioxx.net/licenses/all-rights-reserved/"],"identifier_entries":[]},"links":{"outbound_url":"https://doi.org/10.17863/CAM.51026","outbound_label":"DOI","outbound_source":"dc:identifier.doi"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Davies, Julia"]},{"key":"dc:contributor.sponsor","label":"Sponsor","values":["Yayasan Daya Diri Cambridge Trust Tom ap Rees Fund"]},{"key":"dc:creator","label":"Author","values":["Binti Mohammad Sidik, Amirah"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2020-03-03"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cambridge"]},{"key":"dc:relation.isreferencedby.uri","label":"Dc Relation Isreferencedby URI","values":["https://www.repository.cam.ac.uk/handle/1810/303943"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["extracellular ATP signalling","cytosolic free calcium ion","annexins","salinity stress","DORN1"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/f6624b7f-a23c-482b-bad1-39f21e24c48b/download","https://www.rioxx.net/licenses/all-rights-reserved/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.17863/CAM.51026"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/3f8ec22f-4a0c-4360-9afe-de683b101733/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Extracellular ATP (eATP) is an important signalling molecule in animals but its importance is less understood in plants. Accumulation of eATP in plants occurs in response to biotic and abiotic stresses. eATP causes downstream responses such as increase in cytosolic free calcium ([Ca$^{2+}$]$_{cyt}$), reactive oxygen species (ROS), nitric oxide (NO) and phosphatidic acid (PA). The identification of $\\it{Arabidopsis}$ $\\it{thaliana}$ AtDORN1 (Does Not Respond to Nucleotides) as the first higher plant purinoreceptor has confirmed eATP in plant signalling systems. AtDORN1 is a plasma membrane receptor kinase that appears to command the eATP-induced transient increase in [Ca$^{2+}$]$_{cyt}$ and directs the translational response to wounding. The identity of the plasma membrane Ca$^{2+}$-permeable channels involved in eATP-induced [Ca$^{2+}$]$_{cyt}$ increases remain unknown. Patch clamp electrophysiology has shown that a plasma membrane Ca$^{2+}$ influx conductance lies downstream of the AtRBOHC NADPH oxidase in the response to eATP. As $\\it{Arabidopsis}$ $\\it{thaliana}$ ANNEXIN 1 (AtANN1) underpins ROS-activated plasma membrane Ca$^{2+}$ influx conductance, it has been considered here as operating downstream of AtDORN1 in the eATP-induced increase in [Ca$^{2+}$]$_{cyt}$. In this thesis, the role of AtANN1, AtANN2 and AtANN4 in eATP signalling was tested in $\\it{A.}$ $\\it{thaliana}$. Using (apo)aequorin, AtANN1 and ANNEXIN 2 (AtANN2) have been found to be involved in the root′s [Ca$^{2+}$]$_{cyt}$ response to both eATP and eADP whereas ANNEXIN 4 (AtANN4) might be acting as a negative regulator of AtANN1 (Chapters 3 and 4). Application of Gd$^{3+}$ as a plasma membrane Ca$^{2+}$ channel blocker indicated the possibility of the release of Ca$^{2+}$ from intracellular stores (Chapters 3 and 4). AtANN1 is confirmed to be downstream of the AtDORN1 receptor and also possibly downstream of AtRBOH NADPH Oxidase based on [Ca$^{2+}$]$_{cyt}$ measurement and ROS assays (Chapter 3). Loss${-}$of${-}$function mutants of AtANN1, AtANN2 and AtANN4 altered the eATP${-}$induced gene expression of $\\it{AtACS6}$ but not $\\it{AtWRKY40}$ demonstrating a possible link between eATP signalling and hormone responses in plants (Chapters 3 and 4). Unlike AtANN1 and AtANN4, fewer studies regarding the involvement of AtANN2 in salinity stress and biotic stress were reported. In Chapter 5, results suggest that AtANN2 might not be part of the components mediating salinity stress and biotic stress in plants."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["17b4be3ca959f4ca4527fda1e1833779","87eda9de84448d1f82354d60eee3eb5f"]},{"key":"dc:title","label":"Title","values":["The Role of Arabidopsis thaliana Annexins 1, 2 and 4 in Extracellular ATP Signalling"]}]}],"canonical_facts":{"dc:contributor.advisor":["Davies, Julia"],"dc:contributor.sponsor":["Yayasan Daya Diri Cambridge Trust Tom ap Rees Fund"],"dc:creator":["Binti Mohammad Sidik, Amirah"],"dc:date.issued":["2020-03-03"],"dc:description.abstract":["Extracellular ATP (eATP) is an important signalling molecule in animals but its importance is less understood in plants. Accumulation of eATP in plants occurs in response to biotic and abiotic stresses. eATP causes downstream responses such as increase in cytosolic free calcium ([Ca$^{2+}$]$_{cyt}$), reactive oxygen species (ROS), nitric oxide (NO) and phosphatidic acid (PA). The identification of $\\it{Arabidopsis}$ $\\it{thaliana}$ AtDORN1 (Does Not Respond to Nucleotides) as the first higher plant purinoreceptor has confirmed eATP in plant signalling systems. AtDORN1 is a plasma membrane receptor kinase that appears to command the eATP-induced transient increase in [Ca$^{2+}$]$_{cyt}$ and directs the translational response to wounding. The identity of the plasma membrane Ca$^{2+}$-permeable channels involved in eATP-induced [Ca$^{2+}$]$_{cyt}$ increases remain unknown. Patch clamp electrophysiology has shown that a plasma membrane Ca$^{2+}$ influx conductance lies downstream of the AtRBOHC NADPH oxidase in the response to eATP. As $\\it{Arabidopsis}$ $\\it{thaliana}$ ANNEXIN 1 (AtANN1) underpins ROS-activated plasma membrane Ca$^{2+}$ influx conductance, it has been considered here as operating downstream of AtDORN1 in the eATP-induced increase in [Ca$^{2+}$]$_{cyt}$. In this thesis, the role of AtANN1, AtANN2 and AtANN4 in eATP signalling was tested in $\\it{A.}$ $\\it{thaliana}$. Using (apo)aequorin, AtANN1 and ANNEXIN 2 (AtANN2) have been found to be involved in the root′s [Ca$^{2+}$]$_{cyt}$ response to both eATP and eADP whereas ANNEXIN 4 (AtANN4) might be acting as a negative regulator of AtANN1 (Chapters 3 and 4). Application of Gd$^{3+}$ as a plasma membrane Ca$^{2+}$ channel blocker indicated the possibility of the release of Ca$^{2+}$ from intracellular stores (Chapters 3 and 4). AtANN1 is confirmed to be downstream of the AtDORN1 receptor and also possibly downstream of AtRBOH NADPH Oxidase based on [Ca$^{2+}$]$_{cyt}$ measurement and ROS assays (Chapter 3). Loss${-}$of${-}$function mutants of AtANN1, AtANN2 and AtANN4 altered the eATP${-}$induced gene expression of $\\it{AtACS6}$ but not $\\it{AtWRKY40}$ demonstrating a possible link between eATP signalling and hormone responses in plants (Chapters 3 and 4). Unlike AtANN1 and AtANN4, fewer studies regarding the involvement of AtANN2 in salinity stress and biotic stress were reported. In Chapter 5, results suggest that AtANN2 might not be part of the components mediating salinity stress and biotic stress in plants."],"dc:format.checksum.md5":["17b4be3ca959f4ca4527fda1e1833779","87eda9de84448d1f82354d60eee3eb5f"],"dc:identifier.doi":["10.17863/CAM.51026"],"dc:identifier.uri":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/3f8ec22f-4a0c-4360-9afe-de683b101733/download"],"dc:language":["en"],"dc:publisher.institution":["University of Cambridge"],"dc:relation.isreferencedby.uri":["https://www.repository.cam.ac.uk/handle/1810/303943"],"dc:rights":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/f6624b7f-a23c-482b-bad1-39f21e24c48b/download","https://www.rioxx.net/licenses/all-rights-reserved/"],"dc:subject":["extracellular ATP signalling","cytosolic free calcium ion","annexins","salinity stress","DORN1"],"dc:title":["The Role of Arabidopsis thaliana Annexins 1, 2 and 4 in Extracellular ATP Signalling"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-22T22:24:06Z"}