Plant-Specific Preprotein and Amino Acid Transporter Proteins Are Required for tRNA Import into Mitochondria

Murcha, Monika W.; Kubiszewski-Jakubiak, Szymon; Teixeira, Pedro Filipe; Gügel, Irene L.; Kmiec, Beata; Narsai, Reena; Ivanova, Aneta; Megel, Cyrille; Schock, Annette; Kraus, Sabrina; Berkowitz, Oliver; Glaser, Elzbieta; Philippar, Katrin; Maréchal-Drouard, Laurence; Soll, Jürgen; Whelan, James

doi:10.1104/pp.16.01519

Cited by 27 publications

(68 citation statements)

References 92 publications

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“…Consistent with previous results (Rossig et al ), none of the RNAi plants had a visible phenotype if grown under continuous white light illumination. However, when cultivated under 16 h white light 8 h dark cycles, plant growth was retarded and, depending on the light intensity used, gave rise to a chlorotic phenotype similar to that described by Murcha et al () for tric1::tric2 ( hp30::hp30‐2 ) double mutants. Strikingly, etiolated RNAi plants were conditionally seedling‐lethal and died when illuminated (Figures A, S15).…”

Section: Resultssupporting

confidence: 69%

“…Rupture of the outer mitochondrial membrane following import but prior to protease digestion, resulted in a protease‐protected fragment of 35 S‐HP30‐2 (Figure H, panel a). The appearance of this fragment was reminiscent of that routinely obtained for the inner mitochondrial membrane protein TIM23‐2 that is broken down up to its membrane portion by protease (Murcha et al ) (Figure H, panel b). Addition of valinomycin dissipating the ΔΨ, followed by rupture of the outer mitochondrial membrane, resulted in the degradation of imported 35 S‐HP30‐2 and 35 S‐TIM23‐2 by added proteinase K (Figure H), a result consistent with what is expected for an integral inner membrane protein that could not reach its final destination and accumulated in the intermembrane space.…”

Section: Resultssupporting

confidence: 58%

“…As discussed in the SI section, high expression of fluorescence marker can easily give rise to artifacts. On the other hand, Murcha et al () pointed out that not in all cells analyzed could a dual location be observed and that often fluorescence appeared associated with one or the other organelle type. Thus, these results must be interpreted with caution.…”

Section: Discussionmentioning

confidence: 99%

“…The observed abolition of tRNA Ala import correlated with growth defects, leading to a retardation of development and a chlorotic plant appearance (Murcha et al ). The authors concluded that HP30 and HP30‐2 are essential for mitochondrial tRNA import in Arabidopsis thaliana (Murcha et al ).…”

Section: Introductionmentioning

confidence: 99%

“…Previous work in fact had suggested a dual localization of HP30 and HP30‐2 in chloroplasts and mitochondria (Drea et al ; Murcha et al ). Recently, Murcha et al () suggested mitochondrial HP30 and HP30‐2 to cooperatively function in tRNA import. Broadly, two mechanisms of tRNA import into mitochondria have been described (Mirande ; Adhya ; Schneider for reviews).…”

Section: Introductionmentioning

confidence: 99%

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HP30‐2, a mitochondrial PRAT protein for import of signal sequence‐less precursor proteins in Arabidopsis thaliana

Roßig

Gray

Valdes

et al. 2017

JIPB

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Chloroplasts and mitochondria contain a family of putative preprotein and amino acid transporters designated PRAT. Here, we analyzed the role of two previously characterized PRAT protein family members, encoded by At3g49560 (HP30) and At5g24650 (HP30-2), in planta using a combination of genetic, cell biological and biochemical approaches. Expression studies and green fluorescent protein tagging identified HP30-2 both in chloroplasts and mitochondria, whereas HP30 was located exclusively in chloroplasts. Biochemical evidence was obtained for an association of mitochondrial HP30-2 with two distinct protein complexes, one containing the inner membrane translocase TIM22 and the other containing an alternative NAD(P)H dehydrogenase subunit (NDC1) implicated in a respiratory complex 1-like electron transport chain. Through its association with TIM22, HP30-2 is involved in the uptake of carrier proteins and other, hydrophobic membrane proteins lacking cleavable NH -terminal presequences, whereas HP30-2's interaction with NDC1 may permit controlling mitochondrial biogenesis and activity.

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Section: Resultssupporting

confidence: 69%

Section: Resultssupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

HP30‐2, a mitochondrial PRAT protein for import of signal sequence‐less precursor proteins in Arabidopsis thaliana

Roßig

Gray

Valdes

et al. 2017

JIPB

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Plant Mitochondria

Ghifari¹,

Murcha²

2020

Encyclopedia of Life Sciences

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Plant mitochondria, like the mitochondria of other eukaryotes, originated from an endosymbiotic event and have retained their own genome. Over a billion years of evolution, most mitochondrial genes are laterally transferred to the nucleus. Consequently, most proteins required for mitochondrial biogenesis and activity are synthesised in the cytosol and imported via specific protein import machineries. Mitochondria are energy‐generating organelles that via electron transfer chain (ETC), create a proton gradient and generate adenosine triphosphate (ATP), the energy chemical used by the cell for numerous biochemical reactions. Energy production can come at a cost as reactive oxygen species (ROS) are generated as by‐product. Plant mitochondria have alternative ETC pathways to regulate mitochondrial ROS (mtROS) through modulating the rate of redox reactions, proton gradient and ATP production. Although excessive ROS can damage cellular components and lead to programmed cell death, mtROS also play an important role as signalling molecules. mtROS are involved in nucleus–mitochondria communications (anterograde–retrograde signalling), mitochondrial autophagy (mitophagy) and play a role in the plant response to various environmental stimuli. Considering the pivotal roles of mitochondria in energy generation and cellular signalling, perturbation of mitochondrial biogenesis and activity renders plants to be more susceptible to various stresses and ultimately compromises plant growth, development and reproduction. Key Concepts Plant mitochondria are small (1–2 μm long) rod‐shaped organelle that undergo frequent fusion and fission events. The plant mitochondrial inner membrane houses protein complexes involved in the electron transfer chain (ETC) that creates a proton‐motive gradient across the intermembrane space to drive the production of adenosine triphosphate (ATP) through ATP synthase. The majority of plant mitochondrial proteins (approximately 2000) are encoded in the nuclear genome, whereas the plant mitochondrial genome contains around 50 genes encoding for ETC subunits, mitoribosomal translation machinery and transfer ribonucleic acids (tRNAs). The abundance of mtROS produced by the ETC is proportionally linked with the efficiency and rate of electron transfer and ATP production. Plant mitochondria have alternative ETC pathways to modulate ROS homeostasis, proton gradient and ATP production. mtROS can damage mitochondrial macromolecules and ultimately organelle function but are also important signalling molecules in various pathways, including stress response and anterograde–retrograde signalling. The nucleus controls mitochondrial gene expression through anterograde signalling, yet the mitochondria can also influence nuclear gene expression through retrograde signalling. Disrupted plant mitochondrial function often causes enhanced sensitivity to a number of stresses, disrupted pollen development in cytoplasmic male sterility and affects normal plant growth and development.

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Intercompartment RNA Trafficking in Mitochondrial Function and Communication

Weber-Lotfi

Dietrich

2018

RNA Metabolism in Mitochondria

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Plant-Specific Preprotein and Amino Acid Transporter Proteins Are Required for tRNA Import into Mitochondria

Cited by 27 publications

References 92 publications

HP30‐2, a mitochondrial PRAT protein for import of signal sequence‐less precursor proteins in Arabidopsis thaliana

HP30‐2, a mitochondrial PRAT protein for import of signal sequence‐less precursor proteins in Arabidopsis thaliana

Plant Mitochondria

Intercompartment RNA Trafficking in Mitochondrial Function and Communication

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