Import of Nuclear-Encoded Mitochondrial Proteins

Glaser, Elzbieta; Whelan, James

doi:10.1002/9780470986592.ch4

Cited by 3 publications

(1 citation statement)

References 242 publications

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“…Mitochondrial homeostasis depends on the coordinated activities of proteins encoded by both the nuclear and mitochondrial genomes. Given that nearly 99% of mitochondrial proteins are encoded by the nuclear genome, an efficient import system involving components from both the cytosol and mitochondria is essential (Lister et al ., 2005; Glaser, Whelan and Logan, 2007; Chacinska et al ., 2009; Murcha et al ., 2014). Disruption in mitochondrial function significantly impacts plant’s well-being, leading to substantial impairments in seed germination, growth, flowering, photosynthesis, respiration efficiency, regulation of reactive oxygen species (ROS), and stress sensitivity (Schwarzländer and Finkemeier, 2013; Wang et al ., 2018; Farooq et al ., 2021; Van Aken, 2021).…”

Section: Introductionmentioning

confidence: 99%

Cytosolic Class I J-domain proteins aid mitochondrial protein import and influence homeostasis inArabidopsis thaliana

Lal,

Neha,

Yadav

et al. 2024

Preprint

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Mitochondrial homeostasis heavily relies on import of numerous nuclear encoded proteins. Multiple chaperone machineries operate at the cytosolic and mitochondrial side of the bilayer to ensure the efficacy of this process. While the mechanisms and components involved in translocation of polypeptides into the mitochondria are known in great detail, the cytosolic events of mitochondrial protein import are poorly understood in plants. This study explores the role of two cytosolic Class I J-domain proteins (JDPs), atDjA1 and atDjA2, in mitochondrial homeostasis in Arabidopsis thaliana. We show that atDjA1 and atDjA2 uniquely interacted with outer mitochondrial surface receptors, Tom9, Metaxin, and OM64, which guide the import of numerous mitochondrial precursors. Knockout of atDjA1 or atDjA2 impeded seed germination under multiple abiotic stress conditions, with atDjA1 mutant being more sensitive. Both the mutants demonstrated decreased respiratory rates and enhanced accumulation of reactive oxygen species (ROS), indicating compromised mitochondrial function. Further, knockout of atDjA1 resulted in a significant decline in the number of active mitochondria as well as import of MTS-GFP. While atDjA2 mutants did not show a reduction in mitochondrial number, both the mutants had an activated mitochondrial retrograde signaling (MRS) further underscoring compromised mitochondrial homeostasis in these mutants. Our findings suggest that evolutionarily conserved cytosolic Class I JDPs preserve mitochondrial homeostasis by targeting specific receptors on the outer mitochondrial surface, facilitating the import of cytosolically synthesized mitochondrial precursors in Arabidopsis thaliana.

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Section: Introductionmentioning

confidence: 99%

Cytosolic Class I J-domain proteins aid mitochondrial protein import and influence homeostasis inArabidopsis thaliana

Lal,

Neha,

Yadav

et al. 2024

Preprint

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Acquisition, Conservation, and Loss of Dual-Targeted Proteins in Land Plants

et al. 2012

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The dual-targeting ability of a variety of proteins from Physcomitrella patens, rice (Oryza sativa), and Arabidopsis (Arabidopsis thaliana) was tested to determine when dual targeting arose and to what extent it was conserved in land plants. Overall, the targeting ability of over 80 different proteins from rice and P. patens, representing 42 dual-targeted proteins in Arabidopsis, was tested. We found that dual targeting arose early in land plant evolution, as it was evident in many cases with P. patens proteins that were conserved in rice and Arabidopsis. Furthermore, we found that the acquisition of dual-targeting ability is still occurring, evident in P. patens as well as rice and Arabidopsis. The loss of dual-targeting ability appears to be rare, but does occur. Ascorbate peroxidase represents such an example. After gene duplication in rice, individual genes encode proteins that are targeted to a single organelle. Although we found that dual targeting was generally conserved, the ability to detect dualtargeted proteins differed depending on the cell types used. Furthermore, it appears that small changes in the targeting signal can result in a loss (or gain) of dual-targeting ability. Overall, examination of the targeting signals within this study did not reveal any clear patterns that would predict dual-targeting ability. The acquisition of dual-targeting ability also appears to be coordinated between proteins. Mitochondrial intermembrane space import and assembly protein40, a protein involved in oxidative folding in mitochondria and peroxisomes, provides an example where acquisition of dual targeting is accompanied by the dual targeting of substrate proteins.

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Mitochondrial Biogenesis and Function in Arabidopsis^†

Millar

Small

Day

et al. 2008

The Arabidopsis Book

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Mitochondria represent the powerhouse of cells through their synthesis of ATP. However, understanding the role of mitochondria in the growth and development of plants will rely on a much deeper appreciation of the complexity of this organelle. Arabidopsis research has provided clear identification of mitochondrial components, allowed wide-scale analysis of gene expression, and has aided reverse genetic manipulation to test the impact of mitochondrial component loss on plant function. Forward genetics in Arabidopsis has identified mitochondrial involvement in mutations with notable impacts on plant metabolism, growth and development. Here we consider the evidence for components involved in mitochondria biogenesis, metabolism and signalling to the nucleus.

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Import of Nuclear-Encoded Mitochondrial Proteins

Cited by 3 publications

References 242 publications

Cytosolic Class I J-domain proteins aid mitochondrial protein import and influence homeostasis inArabidopsis thaliana

Cytosolic Class I J-domain proteins aid mitochondrial protein import and influence homeostasis inArabidopsis thaliana

Acquisition, Conservation, and Loss of Dual-Targeted Proteins in Land Plants

Mitochondrial Biogenesis and Function in Arabidopsis^†

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Import of Nuclear-Encoded Mitochondrial Proteins

Cited by 3 publications

References 242 publications

Cytosolic Class I J-domain proteins aid mitochondrial protein import and influence homeostasis inArabidopsis thaliana

Cytosolic Class I J-domain proteins aid mitochondrial protein import and influence homeostasis inArabidopsis thaliana

Acquisition, Conservation, and Loss of Dual-Targeted Proteins in Land Plants

Mitochondrial Biogenesis and Function in Arabidopsis†

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Mitochondrial Biogenesis and Function in Arabidopsis^†