A Mitochondrial Odyssey

Neupert, Walter

doi:10.1146/annurev-biochem-083109-171531

Cited by 9 publications

(13 citation statements)

References 137 publications

(90 reference statements)

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“…All 3 TOM proteins are essential for the formation of intact mitochondria and cooperate in the passage of precursors into the TOM40 import channel in the outer mitochondrial membrane. [2][3][4] Import of pre-sequence-containing and pre-sequence-less precursors in fact converges at TOM40. [2][3][4] Numerous other TOM proteins assist in subsequent steps of mitochondrial protein import.…”

Section: Common Principles Of Protein Translocation Across Membranesmentioning

confidence: 93%

“…[2][3][4] Import of pre-sequence-containing and pre-sequence-less precursors in fact converges at TOM40. [2][3][4] Numerous other TOM proteins assist in subsequent steps of mitochondrial protein import. [2][3][4] Import of pre-sequence-containing chloroplast precursors is mediated by at least 3 proteins: the 2 GTP binding receptors TOC159 and TOC34, and the β-barrel protein and translocation channel TOC75 [5][6][7][8] .…”

Section: Common Principles Of Protein Translocation Across Membranesmentioning

confidence: 93%

“…1 Methods that have led to the identification of these principles include protein biochemistry, cell biology, and genetics. [2][3][4][5][6][7][8] For example, it was found that mitochondria contain 2 types of receptors on their outer surface to bind cytosolic precursors for import. Mitochondrial precursors containing cleavable NH 2 -terminal pre-sequences interact with TOM20.…”

Section: Common Principles Of Protein Translocation Across Membranesmentioning

confidence: 99%

“…[2][3][4] Numerous other TOM proteins assist in subsequent steps of mitochondrial protein import. [2][3][4] Import of pre-sequence-containing chloroplast precursors is mediated by at least 3 proteins: the 2 GTP binding receptors TOC159 and TOC34, and the β-barrel protein and translocation channel TOC75 [5][6][7][8] . TOC159 and TOC34 are encoded by small gene families in Arabidopsis thaliana, with AtTOC159 containing 4 members, designated Attoc159, Attoc132, Attoc120, and Attoc90, and AtTOC34 containing 2 members, named Attoc34 and Attoc33.…”

Section: Common Principles Of Protein Translocation Across Membranesmentioning

confidence: 99%

“…15,16 Indeed, the mitochondrial PRAT family members TIM23 and TIM22 establish the core components for the uptake of newly synthesized cytosolic proteins into the mitochondrial inner membrane. [2][3][4] For the third mitochondrial PRAT protein, TIM17, the exact function has not been resolved, although some evidence suggests that it may operate as a voltage sensor. 30,31 There is a functional specialization among the mitochondrial PRAT proteins.…”

Section: Hp20 Hp30 and Hp30-2 Are Prat Proteins With Novel Functionmentioning

confidence: 99%

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New functions of the chloroplast Preprotein and Amino acid Transporter (PRAT) family members in protein import

Roßig

Reinbothe

Gray

et al. 2014

Plant Signaling & Behavior

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Common principles of protein translocation across membranesCells contain different, membrane-limited compartments endowed with specific proteins. To maintain these compartments, cells have developed elaborate systems for transporting the cell's few thousand different proteins to their final location. Export and import systems have been identified in bacteria and eukaryotes that operate by a similar set of principles.1 Each protein carries NH 2 -terminal or internal targeting information that is recognized by cytoplasmic targeting factors and directs the protein to specific receptors on the target membrane; the targeting signal interacts with a hetero-oligomeric trans-membrane channel that is gated both across and within the plane of the membrane. Molecular chaperones act as nucleoside triphosphate-powered import motors and interact with both the translocating polypeptide chain and the protein-conducting channel. Methods that have led to the identification of these principles include protein biochemistry, cell biology, and genetics.2-8 For example, it was found that mitochondria contain 2 types of receptors on their outer surface to bind cytosolic precursors for import. Mitochondrial precursors containing cleavable NH 2 -terminal pre-sequences interact with TOM20. By contrast, carrier proteins and other hydrophobic membrane proteins lacking cleavable NH 2 -terminal pre-sequences bind TOM70. A third TOM protein, TOM22, was found to associate with both TOM70 and TOM20. All 3 TOM proteins are essential for the formation of intact mitochondria and cooperate in the passage of precursors into the TOM40 import channel in the outer mitochondrial membrane.2-4 Import of pre-sequence-containing and pre-sequence-less precursors in fact converges at TOM40. 2-4Numerous other TOM proteins assist in subsequent steps of mitochondrial protein import. 2-4Import of pre-sequence-containing chloroplast precursors is mediated by at least 3 proteins: the 2 GTP binding receptors TOC159 and TOC34, and the β-barrel protein and translocation channel TOC75 5-8 . TOC159 and TOC34 are encoded by small gene families in Arabidopsis thaliana, with AtTOC159 containing 4 members, designated Attoc159, Attoc132, Attoc120, and Attoc90, and AtTOC34 containing 2 members, named Attoc34 and Attoc33. Biochemical and genetic evidence suggests that there is a functional specialization among the different members of the guanosine triphosphate hydrolyzing GTPase receptor families. 5-8Import of most pre-sequence-containing cytosolic precursors is Keywords: Membrane transport, Protein translocation, Chloroplasts and mitochondria, TIC and TIM translocons at the inner chloroplast envelope and inner mitochondrial membrane, TOC and TOM translocons at outer chloroplast and outer mitochondrial membrane, PRAT protein evolutionPlant cells contain distinct compartments such as the nucleus, the endomembrane system comprising the endoplasmic reticulum and Golgi apparatus, peroxisomes, vacuoles, as well as mitochondria and chloroplasts. All of these compartments are surroun...

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Section: Common Principles Of Protein Translocation Across Membranesmentioning

confidence: 93%

Section: Common Principles Of Protein Translocation Across Membranesmentioning

confidence: 93%

Section: Common Principles Of Protein Translocation Across Membranesmentioning

confidence: 99%

Section: Common Principles Of Protein Translocation Across Membranesmentioning

confidence: 99%

Section: Hp20 Hp30 and Hp30-2 Are Prat Proteins With Novel Functionmentioning

confidence: 99%

See 3 more Smart Citations

New functions of the chloroplast Preprotein and Amino acid Transporter (PRAT) family members in protein import

Roßig

Reinbothe

Gray

et al. 2014

Plant Signaling & Behavior

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Revisiting trends on mitochondrial mega-channels for the import of proteins and nucleic acids

Campo

Peixoto

Martínez-Caballero

2016

J Bioenerg Biomembr

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The discovery of very large channels in the two membranes of mitochondria represented an astonishing finding and a turning point in the awareness of these conspicuous energy-generating organelles. Sizable channels are at the crossroads of important cellular pathways and mitochondrial functions like biogenesis, signaling, secretion, compartmentalization or apoptosis. The integrative approach that combines electrophysiological methods with biochemical and genetic alterations has been decisive to tackle the structure-function relationship of mitochondrial mega-channels. In this review we will give a short account of our joint effort to correlate the existence of large conductance channels in the two membranes of mitochondria with a precise function. In particular, we will focus on the import of proteins and nucleic acids. An analysis of the character of the aqueous pores through which these two types of macromolecules enter mitochondria has been attained, and an up-to date survey of the developments reached in these investigations will be presented. An overlook of the import pathways for proteins and nucleic acids into mitochondria will be outlined. Although this research area is rapidly developing, many issues remain shrouded in uncertainties. A special emphasis will be prone to the not yet entirely settled synergies between different protein translocases.

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