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Kinnally, Kathleen W.; Muro, Concepción; Campo, María Luisa

doi:10.1023/a:1005560328334

Cited by 13 publications

(3 citation statements)

References 57 publications

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“…Comparisons of these activities with those of recombinant proteins Tim23 and Tom40 solidified the assignment of identities (Chich et al, 1991; Fevre et al, 1993, 1994; Henry et al, 1996; Juin et al, 1997; Kinnally et al, 2000; Kunkele et al, 1998b; Thieffry et al, 1992). TOM and TIM23 activities have a peak conductance of ~1 nS in yeast and ~750 pS in mammals (150 mM KCl).…”

Section: The Protein Import Channels Tom Tim23 and Tim22mentioning

confidence: 66%

The therapeutic potential of mitochondrial channels in cancer, ischemia–reperfusion injury, and neurodegeneration

2012

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Mitochondria communicate with the rest of the cell through channels located in their inner and outer membranes. Most of the time, the message is encoded by the flow of anions and cations e.g., through VDAC and PTP, respectively. However, proteins are also both imported and exported across the mitochondrial membranes e.g, through TOM and MAC, respectively. Transport through mitochondrial channels is exquisitely regulated and controls a myriad of processes; from energy production to cell death. Here, we examine the role of some of the mitochondrial channels involved in neurodegeneration, ischemia-reperfusion injury and cancer in the context of their potential as therapeutic targets.

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Section: The Protein Import Channels Tom Tim23 and Tim22mentioning

confidence: 66%

The therapeutic potential of mitochondrial channels in cancer, ischemia–reperfusion injury, and neurodegeneration

2012

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“…In addition to the regulation of transport of ions and small molecules over the mitochondrial membranes, the TSPO also appears to regulate the import of proteins into the mitochondria, including the matrix [ 82 ]. For example, apart from its function as a channel for ions, MCC can serve as the pore of the import complex present in the inner mitochondrial membrane [ 95 ]. In short, MCC is also considered to be a protein import channel.…”

Section: Functional Effects Of Ppix and Synthetic Tspo Ligands In mentioning

confidence: 99%

Tetrapyrroles as Endogenous TSPO Ligands in Eukaryotes and Prokaryotes: Comparisons with Synthetic Ligands

Veenman

Vainshtein

Yasin

et al. 2016

IJMS

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The 18 kDa translocator protein (TSPO) is highly 0conserved in eukaryotes and prokaryotes. Since its discovery in 1977, numerous studies established the TSPO’s importance for life essential functions. For these studies, synthetic TSPO ligands typically are applied. Tetrapyrroles present endogenous ligands for the TSPO. Tetrapyrroles are also evolutionarily conserved and regulate multiple functions. TSPO and tetrapyrroles regulate each other. In animals TSPO-tetrapyrrole interactions range from effects on embryonic development to metabolism, programmed cell death, response to stress, injury and disease, and even to life span extension. In animals TSPOs are primarily located in mitochondria. In plants TSPOs are also present in plastids, the nuclear fraction, the endoplasmic reticulum, and Golgi stacks. This may contribute to translocation of tetrapyrrole intermediates across organelles’ membranes. As in animals, plant TSPO binds heme and protoporphyrin IX. TSPO-tetrapyrrole interactions in plants appear to relate to development as well as stress conditions, including salt tolerance, abscisic acid-induced stress, reactive oxygen species homeostasis, and finally cell death regulation. In bacteria, TSPO is important for switching from aerobic to anaerobic metabolism, including the regulation of photosynthesis. As in mitochondria, in bacteria TSPO is located in the outer membrane. TSPO-tetrapyrrole interactions may be part of the establishment of the bacterial-eukaryote relationships, i.e., mitochondrial-eukaryote and plastid-plant endosymbiotic relationships.

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“…The gating of this protein-selective pore has been extensively studied in patch clamp experiments on isolated mitochondrial membranes. Patch clamping was also instrumental to functional dissection the main TIM23 components (Lohret et al, 1997; Kinnally et al, 2000; Martinez-Caballero et al, 2007a). There are five membrane-spanning TIM23 subunits: Tim23p and Tim17p are thought to be the pore components (Martinez-Caballero et al, 2007a); Tim50p is the main presequence receptor and a putative structural scaffold that links TIM23 to the outer membrane import complex (TOM) (Mokranjac et al, 2009); Tim21p is a transient subunit that has been shown to interact with TOM or with respiratory complexes (Chacinska et al, 2005); Mgr2p/Romo1 bridges TIM23 to the presequence translocase-associated motor (PAM) and is thought to regulate the lateral release of proteins harboring stop-transfer sequences.…”

Section: Introductionmentioning

confidence: 99%

Deletion of Mgr2p Affects the Gating Behavior of the TIM23 Complex

et al. 2019

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The TIM23 complex is a hub for translocation of preproteins into or across the mitochondrial inner membrane. This dual sorting mechanism is currently being investigated, and in yeast appears to be regulated by a recently discovered subunit, the Mgr2 protein. Deletion of Mgr2p has been found to delay protein translocation into the matrix and accumulation in the inner membrane. This result and other findings suggested that Mgr2p controls the lateral release of inner membrane proteins harboring a stop-transfer signal that follows an N-terminal amino acid signal. However, the mechanism of lateral release is unknown. Here, we used patch clamp electrophysiology to investigate the role of Mgr2p on the channel activity of TIM23. Deletion of Mgr2p decreased normal channel frequency and increased occurrence of a residual TIM23 activity. The residual channel lacked gating transitions but remained sensitive to synthetic import signal peptides. Similarly, a G145L mutation in Tim23p displaced Mgr2p from the import complex leading to gating impairment. These results suggest that Mgr2p regulates the gating behavior of the TIM23 channel.

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Untitled

Cited by 13 publications

References 57 publications

The therapeutic potential of mitochondrial channels in cancer, ischemia–reperfusion injury, and neurodegeneration

The therapeutic potential of mitochondrial channels in cancer, ischemia–reperfusion injury, and neurodegeneration

Tetrapyrroles as Endogenous TSPO Ligands in Eukaryotes and Prokaryotes: Comparisons with Synthetic Ligands

Deletion of Mgr2p Affects the Gating Behavior of the TIM23 Complex

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