The EF-hand Ca2+ binding protein MICU choreographs mitochondrial Ca2+ dynamics in arabidopsis
© 2015 American Society of Plant Biologists. All rights reserved. Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca2+ signaling may play a central role in this process. Free Ca2+ dynamics are tightly regulated and differ markedly bet...
| Main Authors: | , , , , , , , , , , , , , , , , , , |
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| Format: | Journal article |
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2015
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| _version_ | 1797063652249960448 |
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| author | Wagner, S Behera, S De Bortoli, S Logan, D Fuchs, P Carraretto, L Teardo, E Cendron, L Nietzel, T Füßl, M Doccula, F Navazio, L Fricker, M Van Aken, O Finkemeier, I Finkemeier, I Meyer, A Szabò, I Costa, A Costa, A Schwarzländer, M |
| author_facet | Wagner, S Behera, S De Bortoli, S Logan, D Fuchs, P Carraretto, L Teardo, E Cendron, L Nietzel, T Füßl, M Doccula, F Navazio, L Fricker, M Van Aken, O Finkemeier, I Finkemeier, I Meyer, A Szabò, I Costa, A Costa, A Schwarzländer, M |
| author_sort | Wagner, S |
| collection | OXFORD |
| description | © 2015 American Society of Plant Biologists. All rights reserved. Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca2+ signaling may play a central role in this process. Free Ca2+ dynamics are tightly regulated and differ markedly between the cytosol, plastid stroma, and mitochondrial matrix. The mechanistic basis of compartment-specific Ca2+ dynamics is poorly understood. Here, we studied the function of At-MICU, an EF-hand protein of Arabidopsis thaliana with homology to constituents of the mitochondrial Ca2+ uniporter machinery in mammals. MICU binds Ca2+ and localizes to the mitochondria in Arabidopsis. In vivo imaging of roots expressing a genetically encoded Ca2+ sensor in the mitochondrial matrix revealed that lack of MICU increased resting concentrations of free Ca2+ in the matrix. Furthermore, Ca2+ elevations triggered by auxin and extracellular ATP occurred more rapidly and reached higher maximal concentrations in the mitochondria of micu mutants, whereas cytosolic Ca2+ signatures remained unchanged. These findings support the idea that a conserved uniporter system, with composition and regulation distinct from the mammalian machinery, mediates mitochondrial Ca2+ uptake in plants under in vivo conditions. They further suggest that MICU acts as a throttle that controls Ca2+ uptake by moderating influx, thereby shaping Ca2+ signatures in the matrix and preserving mitochondrial homeostasis. Our results open the door to genetic dissection of mitochondrial Ca2+ signaling in plants. |
| first_indexed | 2024-03-06T21:02:59Z |
| format | Journal article |
| id | oxford-uuid:3b7d2268-2f18-4416-9312-33f3b078ae61 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T21:02:59Z |
| publishDate | 2015 |
| record_format | dspace |
| spelling | oxford-uuid:3b7d2268-2f18-4416-9312-33f3b078ae612022-03-26T14:08:00ZThe EF-hand Ca2+ binding protein MICU choreographs mitochondrial Ca2+ dynamics in arabidopsisJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:3b7d2268-2f18-4416-9312-33f3b078ae61Symplectic Elements at Oxford2015Wagner, SBehera, SDe Bortoli, SLogan, DFuchs, PCarraretto, LTeardo, ECendron, LNietzel, TFüßl, MDoccula, FNavazio, LFricker, MVan Aken, OFinkemeier, IFinkemeier, IMeyer, ASzabò, ICosta, ACosta, ASchwarzländer, M© 2015 American Society of Plant Biologists. All rights reserved. Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca2+ signaling may play a central role in this process. Free Ca2+ dynamics are tightly regulated and differ markedly between the cytosol, plastid stroma, and mitochondrial matrix. The mechanistic basis of compartment-specific Ca2+ dynamics is poorly understood. Here, we studied the function of At-MICU, an EF-hand protein of Arabidopsis thaliana with homology to constituents of the mitochondrial Ca2+ uniporter machinery in mammals. MICU binds Ca2+ and localizes to the mitochondria in Arabidopsis. In vivo imaging of roots expressing a genetically encoded Ca2+ sensor in the mitochondrial matrix revealed that lack of MICU increased resting concentrations of free Ca2+ in the matrix. Furthermore, Ca2+ elevations triggered by auxin and extracellular ATP occurred more rapidly and reached higher maximal concentrations in the mitochondria of micu mutants, whereas cytosolic Ca2+ signatures remained unchanged. These findings support the idea that a conserved uniporter system, with composition and regulation distinct from the mammalian machinery, mediates mitochondrial Ca2+ uptake in plants under in vivo conditions. They further suggest that MICU acts as a throttle that controls Ca2+ uptake by moderating influx, thereby shaping Ca2+ signatures in the matrix and preserving mitochondrial homeostasis. Our results open the door to genetic dissection of mitochondrial Ca2+ signaling in plants. |
| spellingShingle | Wagner, S Behera, S De Bortoli, S Logan, D Fuchs, P Carraretto, L Teardo, E Cendron, L Nietzel, T Füßl, M Doccula, F Navazio, L Fricker, M Van Aken, O Finkemeier, I Finkemeier, I Meyer, A Szabò, I Costa, A Costa, A Schwarzländer, M The EF-hand Ca2+ binding protein MICU choreographs mitochondrial Ca2+ dynamics in arabidopsis |
| title | The EF-hand Ca2+ binding protein MICU choreographs mitochondrial Ca2+ dynamics in arabidopsis |
| title_full | The EF-hand Ca2+ binding protein MICU choreographs mitochondrial Ca2+ dynamics in arabidopsis |
| title_fullStr | The EF-hand Ca2+ binding protein MICU choreographs mitochondrial Ca2+ dynamics in arabidopsis |
| title_full_unstemmed | The EF-hand Ca2+ binding protein MICU choreographs mitochondrial Ca2+ dynamics in arabidopsis |
| title_short | The EF-hand Ca2+ binding protein MICU choreographs mitochondrial Ca2+ dynamics in arabidopsis |
| title_sort | ef hand ca2 binding protein micu choreographs mitochondrial ca2 dynamics in arabidopsis |
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