The EF-Hand Ca2+ Binding Protein MICU Choreographs Mitochondrial Ca2+ Dynamics in Arabidopsis
(2015) In Plant Cell 27(11). p.212-3190- Abstract
Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca(2+) signaling may play a central role in this process. Free Ca(2+) dynamics are tightly regulated and differ markedly between the cytosol, plastid stroma, and mitochondrial matrix. The mechanistic basis of compartment-specific Ca(2+) 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 Ca(2+) uniporter machinery in mammals. MICU binds Ca(2+) and localizes to the mitochondria in Arabidopsis. In vivo imaging of roots expressing a genetically encoded Ca(2+) sensor in the mitochondrial matrix revealed that lack of... (More)
Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca(2+) signaling may play a central role in this process. Free Ca(2+) dynamics are tightly regulated and differ markedly between the cytosol, plastid stroma, and mitochondrial matrix. The mechanistic basis of compartment-specific Ca(2+) 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 Ca(2+) uniporter machinery in mammals. MICU binds Ca(2+) and localizes to the mitochondria in Arabidopsis. In vivo imaging of roots expressing a genetically encoded Ca(2+) sensor in the mitochondrial matrix revealed that lack of MICU increased resting concentrations of free Ca(2+) in the matrix. Furthermore, Ca(2+) elevations triggered by auxin and extracellular ATP occurred more rapidly and reached higher maximal concentrations in the mitochondria of micu mutants, whereas cytosolic Ca(2+) signatures remained unchanged. These findings support the idea that a conserved uniporter system, with composition and regulation distinct from the mammalian machinery, mediates mitochondrial Ca(2+) uptake in plants under in vivo conditions. They further suggest that MICU acts as a throttle that controls Ca(2+) uptake by moderating influx, thereby shaping Ca(2+) signatures in the matrix and preserving mitochondrial homeostasis. Our results open the door to genetic dissection of mitochondrial Ca(2+) signaling in plants.
(Less)
- author
- publishing date
- 2015-11
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Arabidopsis, Arabidopsis Proteins, Calcium, Calcium Signaling, Calcium-Binding Proteins, Cell Respiration, Cytosol, DNA, Bacterial, EF Hand Motifs, Mitochondria, Mutagenesis, Insertional, Phylogeny, Plant Roots, Protein Binding, Protein Transport, Seedlings, Sequence Homology, Amino Acid, Subcellular Fractions, Journal Article, Research Support, Non-U.S. Gov't
- in
- Plant Cell
- volume
- 27
- issue
- 11
- pages
- 23 pages
- publisher
- American Society of Plant Biologists
- external identifiers
-
- scopus:84949665651
- pmid:26530087
- ISSN
- 1040-4651
- DOI
- 10.1105/tpc.15.00509
- language
- English
- LU publication?
- no
- id
- e194396e-b886-41df-a641-7f82201cd6eb
- date added to LUP
- 2017-05-08 10:46:48
- date last changed
- 2024-03-31 07:23:31
@article{e194396e-b886-41df-a641-7f82201cd6eb,
abstract = {{<p>Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca(2+) signaling may play a central role in this process. Free Ca(2+) dynamics are tightly regulated and differ markedly between the cytosol, plastid stroma, and mitochondrial matrix. The mechanistic basis of compartment-specific Ca(2+) 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 Ca(2+) uniporter machinery in mammals. MICU binds Ca(2+) and localizes to the mitochondria in Arabidopsis. In vivo imaging of roots expressing a genetically encoded Ca(2+) sensor in the mitochondrial matrix revealed that lack of MICU increased resting concentrations of free Ca(2+) in the matrix. Furthermore, Ca(2+) elevations triggered by auxin and extracellular ATP occurred more rapidly and reached higher maximal concentrations in the mitochondria of micu mutants, whereas cytosolic Ca(2+) signatures remained unchanged. These findings support the idea that a conserved uniporter system, with composition and regulation distinct from the mammalian machinery, mediates mitochondrial Ca(2+) uptake in plants under in vivo conditions. They further suggest that MICU acts as a throttle that controls Ca(2+) uptake by moderating influx, thereby shaping Ca(2+) signatures in the matrix and preserving mitochondrial homeostasis. Our results open the door to genetic dissection of mitochondrial Ca(2+) signaling in plants.</p>}},
author = {{Wagner, Stephan and Behera, Smrutisanjita and De Bortoli, Sara and Logan, David C and Fuchs, Philippe and Carraretto, Luca and Teardo, Enrico and Cendron, Laura and Nietzel, Thomas and Füßl, Magdalena and Doccula, Fabrizio G and Navazio, Lorella and Fricker, Mark D and Van Aken, Olivier and Finkemeier, Iris and Meyer, Andreas J and Szabò, Ildikò and Costa, Alex and Schwarzländer, Markus}},
issn = {{1040-4651}},
keywords = {{Arabidopsis; Arabidopsis Proteins; Calcium; Calcium Signaling; Calcium-Binding Proteins; Cell Respiration; Cytosol; DNA, Bacterial; EF Hand Motifs; Mitochondria; Mutagenesis, Insertional; Phylogeny; Plant Roots; Protein Binding; Protein Transport; Seedlings; Sequence Homology, Amino Acid; Subcellular Fractions; Journal Article; Research Support, Non-U.S. Gov't}},
language = {{eng}},
number = {{11}},
pages = {{212--3190}},
publisher = {{American Society of Plant Biologists}},
series = {{Plant Cell}},
title = {{The EF-Hand Ca2+ Binding Protein MICU Choreographs Mitochondrial Ca2+ Dynamics in Arabidopsis}},
url = {{http://dx.doi.org/10.1105/tpc.15.00509}},
doi = {{10.1105/tpc.15.00509}},
volume = {{27}},
year = {{2015}},
}