Import of Mitochondrial Carriers Mediated by Essential Proteins of the Intermembrane Space

Koehler, Carla M.; Jarosch, Ernst; Tokatlidis, Kostas; Schmid, Karl; Schweyen, Rudolf J.; Schatz, Gottfried

doi:10.1126/science.279.5349.369

Cited by 291 publications

(365 citation statements)

References 28 publications

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“…Previous results have also revealed several interaction partners of small proteins. Tim12, a small peripheral membrane subunit of TIM22 translocation component with a molecular mass of 12 kDa, has been shown to interact directly with Tim9, Tim10, Tim22 and carrier proteins, and delivers these carrier proteins to the inner membrane 47,48 . Distinct properties of N-and C-terminal ends of Tim12 have been demonstrated to be important for its interactions and functions 47 .…”

Section: Discussionmentioning

confidence: 99%

LTD is a protein required for sorting light-harvesting chlorophyll-binding proteins to the chloroplast SRP pathway

Ouyang

et al. 2011

Nat Commun

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Higher plants require chloroplasts for essential functions in photosynthesis and other important physiological processes, such as sugar, lipid and amino-acid biosynthesis. most chloroplast proteins are nuclear-encoded proteins that are synthesized in the cytosol as precursors, and imported into chloroplasts by protein translocases in the outer and inner chloroplast envelope. The imported chloroplast proteins are then translocated into or across the thylakoid membrane by four distinct pathways. However, the mechanisms by which the imported nuclear-encoded proteins are delivered to these pathways remain largely unknown. Here we show that an Arabidopsis ankyrin protein, LTD (mutation of which causes the light-harvesting chlorophyllbinding protein translocation defect), is localized in the chloroplast and using yeast two-hybrid screens demonstrate that LTD interacts with both proteins from the signal recognition particle (sRP) pathway and the inner chloroplast envelope. our study shows that LTD is essential for the import of light-harvesting chlorophyll-binding proteins and subsequent routing of these proteins to the chloroplast sRP-dependent pathway.

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Section: Discussionmentioning

confidence: 99%

LTD is a protein required for sorting light-harvesting chlorophyll-binding proteins to the chloroplast SRP pathway

Ouyang

et al. 2011

Nat Commun

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“…In contrast, the TIM9/ 10/12 complex is tightly associated with the TIM22 complex at the outer face of the inner membrane. This interaction is probably mediated by Tim12 (120,(128)(129)(130). However, Tim12 was only identi ed in Saccharomyces cerevisiae so far (132).…”

Section: The Tim9/10 and Tim9/10/12 Complexesmentioning

confidence: 99%

“…Finally, two carrier precursors assemble into the functional dimer (stage V). By dissipating the membrane potential or by depleting Tim12, the insertion of the carrier precursor into the inner membrane can be blocked and accumulates at stage IIIa associated with the TIM9/10 and the TOM complex (120,128). Through the association with the carrier precursor, the TIM9/10 complex prevents the retrograde translocation and the misfolding of the hydrophobi c precursor protein in the intermembrane space maintaining an insertion-competent conformation.…”

Section: Import and Assembly Of Mitochondrial Carrier Proteinsmentioning

confidence: 99%

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Protein Import Into Mitochondria

Paschen¹,

Neupert²

2001

IUBMB Life

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SummaryMost mitochondrial proteins are encoded by the nuclear genome and thus have to be imported into mitochondria from the cytosol. Protein translocation across and into the mitochondrial membranes is a multistep process facilitated by the coordinated action of at least four specialized translocation systems in the outer and inner membranes of mitochondria. The outer membrane contains one general translocase, the TOM complex, whereas three distinct translocases are located in the inner membrane, which facilitates translocation of different classes of preproteins. The TIM23 complex mediates import of matrix-targeted preproteins with Nterminal presequences, whereas hydrophobi c preproteins with internal targeting signals are inserted into the inner membrane via the TIM22 complex. The OXA translocase mediates the insertion of preproteins from the matrix space into the inner membrane. This review focuses on the structural organization and function of the import machinery of the model organisms of Saccharomyces cerevisiae and Neurospora crassa. In addition, the molecular basis of a new human mitochondrial disorder is discussed, the MohrTranebjaerg syndrome. This is the rst known disease, which is caused by an impaired mitochondrial protein import machinery leading to progressive neurodegeneration.

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“…Transfer from this stage to the next one requires energy in the form of ATP hydrolysis [8]. In stage III, the AAC crosses the OM through the TOM channel in a loop conformation and is bound by the soluble, intermembrane space (IMS) 70 kDa complex made of Tim9 and Tim10 [5,[9][10][11][12]. In stage IV, the precursor is targeted to the IM where it is inserted by the TIM22 complex [13,14].…”

Section: Introductionmentioning

confidence: 99%

A cryptic matrix targeting signal of the yeast ADP/ATP carrier normally inserted by the TIM22 complex is recognized by the TIM23 machinery

Vergnolle

Sawney

Junne

et al. 2004

Biochemical Journal

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The yeast ADP/ATP carrier (AAC) is a mitochondrial protein that is targeted to the inner membrane via the TIM10 and TIM22 translocase complexes. AAC is devoid of a typical mitochondrial targeting signal and its targeting and insertion are thought to be guided by internal amino acid sequences. Here we show that AAC contains a cryptic matrix targeting signal that can target up to two thirds of the N-terminal part of the protein to the matrix. This event is coordinated by the TIM23 translocase and displays all the features of the matrix-targeting pathway. However, in the context of the whole protein, this signal is 'masked' and rendered nonfunctional as the polypeptide is targeted to the inner membrane via the TIM10 and TIM22 translocases. Our data suggest that after crossing the outer membrane the whole polypeptide chain of AAC is necessary to commit the precursor to the TIM22-mediated inner membrane insertion pathway.

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Import of Mitochondrial Carriers Mediated by Essential Proteins of the Intermembrane Space

Cited by 291 publications

References 28 publications

LTD is a protein required for sorting light-harvesting chlorophyll-binding proteins to the chloroplast SRP pathway

LTD is a protein required for sorting light-harvesting chlorophyll-binding proteins to the chloroplast SRP pathway

Protein Import Into Mitochondria

A cryptic matrix targeting signal of the yeast ADP/ATP carrier normally inserted by the TIM22 complex is recognized by the TIM23 machinery

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