Dislocation by the m-AAA Protease Increases the Threshold Hydrophobicity for Retention of Transmembrane Helices in the Inner Membrane of Yeast Mitochondria

Botelho, Salomé Calado; Tatsuta, Takashi; Heijne, Gunnar von; Kim, Hyun

doi:10.1074/jbc.m112.430892

Cited by 13 publications

(13 citation statements)

References 25 publications

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“…Recently, the conformational stability has been shown to be a key determinant for the cellular trafficking efficiency of the human membrane protein PMP22 65 . In yeast, the presence of a mitochondrial FtsH ortholog increases the threshold hydrophobicity level of a TM helix for its retention in the inner membrane 66 . Our systematic study dissecting the effects of the two physical forces further supports these observations.…”

Section: Discussionmentioning

confidence: 99%

Folding-Degradation Relationship of a Membrane Protein Mediated by the Universally Conserved ATP-Dependent Protease FtsH

et al. 2018

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ATP-dependent protein degradation mediated by AAA+ proteases is one of the major cellular pathways for protein quality control and regulation of functional networks. While a majority of studies of protein degradation have focused on water-soluble proteins, it is not well understood how membrane proteins with abnormal conformation are selectively degraded. The knowledge gap stems from the lack of an in vitro system in which detailed molecular mechanisms can be studied as well as difficulties in studying membrane protein folding in lipid bilayers. To quantitatively define the folding-degradation relationship of membrane proteins, we reconstituted the degradation using the conserved membrane-integrated AAA+ protease FtsH as a model degradation machine and the stable helical-bundle membrane protein GlpG as a model substrate in the lipid bilayer environment. We demonstrate that FtsH possesses a substantial ability to actively unfold GlpG, and the degradation significantly depends on the stability and hydrophobicity near the degradation marker. We find that FtsH hydrolyzes 380–550 ATP molecules to degrade one copy of GlpG. Remarkably, FtsH overcomes the dual-energetic burden of substrate unfolding and membrane dislocation with the ATP cost comparable to that for water-soluble substrates by robust ClpAP/XP proteases. The physical principles elucidated in this study provide general insights into membrane protein degradation mediated by ATP-dependent proteolytic systems.

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Section: Discussionmentioning

confidence: 99%

Folding-Degradation Relationship of a Membrane Protein Mediated by the Universally Conserved ATP-Dependent Protease FtsH

et al. 2018

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“…This draws the substrate proteins inside the pore and unfolds them (Lee et al, 2001;Langklotz et al, 2012). In yeast mitochondria, the m-AAA protease, described as an ATP-dependent protease that degrades misfolded proteins and mediates protein processing, is proposed to be further involved in the dislocation of imported preproteins from the inner membrane by functioning as an ATP-driven molecular motor (Tatsuta et al, 2007;Botelho et al, 2013). In yeast mitochondria, many nucleus-encoded preproteins are imported into the mitochondrial matrix via the TIM23 translocon (Demishtein-Zohary and Azem, 2017).…”

Section: Possible Role Of the Ftsh12-ftshi Complexmentioning

confidence: 99%

Plastidial NAD-Dependent Malate Dehydrogenase: A Moonlighting Protein Involved in Early Chloroplast Development through Its Interaction with an FtsH12-FtsHi Protease Complex

et al. 2018

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Malate dehydrogenases (MDHs) convert malate to oxaloacetate using NAD(H) or NADP(H) as a cofactor. mutants lacking plastidial NAD-dependent MDH () are embryo-lethal, and constitutive silencing (1) causes a pale, dwarfed phenotype. The reason for these severe phenotypes is unknown. Here, we rescued the embryo lethality of via embryo-specific expression of pdNAD-MDH. Rescued seedlings developed white leaves with aberrant chloroplasts and failed to reproduce. Inducible silencing of pdNAD-MDH at the rosette stage also resulted in white newly emerging leaves. These data suggest that pdNAD-MDH is important for early plastid development, which is consistent with the reductions in major plastidial galactolipid, carotenoid, and protochlorophyllide levels in1 seedlings. Surprisingly, the targeting of other NAD-dependent MDH isoforms to the plastid did not complement the embryo lethality of , while expression of enzymatically inactive pdNAD-MDH did. These complemented plants grew indistinguishably from the wild type. Both active and inactive forms of pdNAD-MDH interact with a heteromeric AAA-ATPase complex at the inner membrane of the chloroplast envelope. Silencing the expression of FtsH12, a key member of this complex, resulted in a phenotype that strongly resembles1. We propose that pdNAD-MDH is essential for chloroplast development due to its moonlighting role in stabilizing FtsH12, distinct from its enzymatic function.

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“…A study examining the retention of simple transmembrane sequences in the MIM demonstrated that sequences required >3:1 leucine:alanine residues to escape dislocation from the membrane by m-AAA. Under this scheme, the protease could extract most MIM proteins (Botelho et al, 2013 ). The central pores of both proteases contain loops bearing the canonical aromatic-hydrophobic (Ar-ϕ) motif that are proposed to deliver the translocating force (Graef and Langer, 2006 ; Martin et al, 2008 ).…”

Section: Mechanisms Of Extraction From the Membranementioning

confidence: 99%

Multifunctional Mitochondrial AAA Proteases

Glynn

2017

Front. Mol. Biosci.

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Mitochondria perform numerous functions necessary for the survival of eukaryotic cells. These activities are coordinated by a diverse complement of proteins encoded in both the nuclear and mitochondrial genomes that must be properly organized and maintained. Misregulation of mitochondrial proteostasis impairs organellar function and can result in the development of severe human diseases. ATP-driven AAA+ proteins play crucial roles in preserving mitochondrial activity by removing and remodeling protein molecules in accordance with the needs of the cell. Two mitochondrial AAA proteases, i-AAA and m-AAA, are anchored to either face of the mitochondrial inner membrane, where they engage and process an array of substrates to impact protein biogenesis, quality control, and the regulation of key metabolic pathways. The functionality of these proteases is extended through multiple substrate-dependent modes of action, including complete degradation, partial processing, or dislocation from the membrane without proteolysis. This review discusses recent advances made toward elucidating the mechanisms of substrate recognition, handling, and degradation that allow these versatile proteases to control diverse activities in this multifunctional organelle.

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Dislocation by the m-AAA Protease Increases the Threshold Hydrophobicity for Retention of Transmembrane Helices in the Inner Membrane of Yeast Mitochondria

Cited by 13 publications

References 25 publications

Folding-Degradation Relationship of a Membrane Protein Mediated by the Universally Conserved ATP-Dependent Protease FtsH

Folding-Degradation Relationship of a Membrane Protein Mediated by the Universally Conserved ATP-Dependent Protease FtsH

Plastidial NAD-Dependent Malate Dehydrogenase: A Moonlighting Protein Involved in Early Chloroplast Development through Its Interaction with an FtsH12-FtsHi Protease Complex

Multifunctional Mitochondrial AAA Proteases

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