scholarly journals Mutations Affecting a Yeast Mitochondrial Inner Membrane Protein, Pnt1p, Block Export of a Mitochondrially Synthesized Fusion Protein from the Matrix

1999 ◽  
Vol 19 (10) ◽  
pp. 6598-6607 ◽  
Author(s):  
Shichuan He ◽  
Thomas D. Fox
Keyword(s):  
Membrane Protein ◽  
Fusion Protein ◽  
Kluyveromyces Lactis ◽  
Nuclear Gene ◽  
Wild Type ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Mitochondrial Target ◽  
The Matrix ◽  
Inner Membrane Protein

ABSTRACT The machinery that inserts mitochondrially encoded proteins into the inner membrane and translocates their hydrophilic domains through the membrane is poorly understood. We have developed a genetic screen for Saccharomyces cerevisiae mutants defective in this export process. The screen is based on the fact that the hydrophilic polypeptide Arg8mp is exported from the matrix if it is synthesized within mitochondria as a bifunctional Cox2p-Arg8mp fusion protein. Since export of Arg8mp causes an Arg− phenotype, defective mutants can be selected as Arg+. Here we show that mutations in the nuclear gene PNT1 block the translocation of mitochondrially encoded fusion proteins across the inner membrane. Pnt1p is a mitochondrial integral inner membrane protein that appears to have two hydrophilic domains in the matrix, flanking a central hydrophobic hairpin-like anchor. While an S. cerevisiae pnt1 deletion mutant was more sensitive to H2O2 than the wild type was, it was respiration competent and able to export wild-type Cox2p. However, deletion of thePNT1 orthologue from Kluyveromyces lactis,KlPNT1, caused a clear nonrespiratory phenotype, absence of cytochrome oxidase activity, and a defect in the assembly of KlCox2p that appears to be due to a block of C-tail export. SincePNT1 was previously described as a gene affecting resistance to the antibiotic pentamidine, our data support a mitochondrial target for this drug.

scholarly journals Peripheral Mitochondrial Inner Membrane Protein, Mss2p, Required for Export of the Mitochondrially Coded Cox2p C Tail inSaccharomyces cerevisiae

2001 ◽  
Vol 21 (22) ◽  
pp. 7663-7672 ◽  
Author(s):  
Sarah A. Broadley ◽  
Christina M. Demlow ◽  
Thomas D. Fox
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Protein ◽  
Cytochrome Oxidase ◽  
Nuclear Gene ◽  
Cytochrome Oxidase Subunit ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
N Terminus ◽  
The Matrix ◽  
Inner Membrane Protein

ABSTRACT Cytochrome oxidase subunit 2 (Cox2p) is synthesized on the matrix side of the mitochondrial inner membrane, and its N- and C-terminal domains are exported across the inner membrane by distinct mechanisms. The Saccharomyces cerevisiaenuclear gene MSS2 was previously shown to be necessary for Cox2p accumulation. We have used pulse-labeling studies and the expression of the ARG8 m reporter at the COX2 locus in an mss2 mutant to demonstrate that Mss2p is not required for Cox2p synthesis but rather for its accumulation. Mutational inactivation of the proteolytic function of the matrix-localized Yta10p (Afg3p) AAA-protease partially stabilizes Cox2p in an mss2 mutant but does not restore assembly of cytochrome oxidase. In the absence of Mss2p, the Cox2p N terminus is exported, but Cox2p C-terminal export and assembly of Cox2p into cytochrome oxidase is blocked. Epitope-tagged Mss2p is tightly, but peripherally, associated with the inner membrane and protected by it from externally added proteases. Taken together, these data indicate that Mss2p plays a role in recognizing the Cox2p C tail in the matrix and promoting its export.

Removal of a hydrophobic domain within the mature portion of a mitochondrial inner membrane protein causes its mislocalization to the matrix

1990 ◽  
Vol 10 (5) ◽  
pp. 1873-1881
Author(s):  
S M Glaser ◽  
B R Miller ◽  
M G Cumsky
Keyword(s):  
Amino Acids ◽  
Mitochondrial Matrix ◽  
Mature Protein ◽  
Wild Type ◽  
Inner Membrane ◽  
Hydrophobic Domain ◽  
Mitochondrial Inner Membrane ◽  
The Matrix ◽  
Inner Membrane Protein ◽  
Cognate Protein

We have examined the import and intramitochondrial localization of the precursor to yeast cytochrome c oxidase subunit Va, a protein of the mitochondrial inner membrane. The results of studies on the import of subunit Va derivatives carrying altered presequences suggest that the uptake of this protein is highly efficient. We found that a presequence of only 5 amino acids (Met-Leu-Ser-Leu-Arg) could direct the import and localization of subunit Va with wild-type efficiency, as judged by several different assays. We also found that subunit Va could be effectively targeted to the mitochondrial inner membrane with a heterologous presequence that failed to direct import of its cognate protein. The results presented here confirmed those of an earlier study and showed clearly that the information required to "sort" subunit Va to the inner membrane resides in the mature protein sequence, not within the presequence per se. We present additional evidence that the aforementioned sorting information is contained, at least in part, in a hydrophobic stretch of 22 amino acids residing within the C-terminal third of the protein. Removal of this domain caused subunit Va to be mislocalized to the mitochondrial matrix.

scholarly journals Removal of a hydrophobic domain within the mature portion of a mitochondrial inner membrane protein causes its mislocalization to the matrix.

1990 ◽  
Vol 10 (5) ◽  
pp. 1873-1881 ◽  
Author(s):  
S M Glaser ◽  
B R Miller ◽  
M G Cumsky
Keyword(s):  
Amino Acids ◽  
Mitochondrial Matrix ◽  
Mature Protein ◽  
Wild Type ◽  
Inner Membrane ◽  
Hydrophobic Domain ◽  
Mitochondrial Inner Membrane ◽  
The Matrix ◽  
Inner Membrane Protein ◽  
Cognate Protein

We have examined the import and intramitochondrial localization of the precursor to yeast cytochrome c oxidase subunit Va, a protein of the mitochondrial inner membrane. The results of studies on the import of subunit Va derivatives carrying altered presequences suggest that the uptake of this protein is highly efficient. We found that a presequence of only 5 amino acids (Met-Leu-Ser-Leu-Arg) could direct the import and localization of subunit Va with wild-type efficiency, as judged by several different assays. We also found that subunit Va could be effectively targeted to the mitochondrial inner membrane with a heterologous presequence that failed to direct import of its cognate protein. The results presented here confirmed those of an earlier study and showed clearly that the information required to "sort" subunit Va to the inner membrane resides in the mature protein sequence, not within the presequence per se. We present additional evidence that the aforementioned sorting information is contained, at least in part, in a hydrophobic stretch of 22 amino acids residing within the C-terminal third of the protein. Removal of this domain caused subunit Va to be mislocalized to the mitochondrial matrix.

scholarly journals YME1L controls the accumulation of respiratory chain subunits and is required for apoptotic resistance, cristae morphogenesis, and cell proliferation

2012 ◽  
Vol 23 (6) ◽  
pp. 1010-1023 ◽  
Author(s):  
Lukas Stiburek ◽  
Jana Cesnekova ◽  
Olga Kostkova ◽  
Daniela Fornuskova ◽  
Kamila Vinsova ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Membrane Protein ◽  
Respiratory Chain ◽  
Integral Membrane Protein ◽  
Intermembrane Space ◽  
Wild Type ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Human Orthologue ◽  
Excessive Accumulation

Mitochondrial ATPases associated with diverse cellular activities (AAA) proteases are involved in the quality control and processing of inner-membrane proteins. Here we investigate the cellular activities of YME1L, the human orthologue of the Yme1 subunit of the yeast i‑AAA complex, using stable short hairpin RNA knockdown and expression experiments. Human YME1L is shown to be an integral membrane protein that exposes its carboxy-terminus to the intermembrane space and exists in several complexes of 600–1100 kDa. The stable knockdown of YME1L in human embryonic kidney 293 cells led to impaired cell proliferation and apoptotic resistance, altered cristae morphology, diminished rotenone-sensitive respiration, and increased susceptibility to mitochondrial membrane protein carbonylation. Depletion of YME1L led to excessive accumulation of nonassembled respiratory chain subunits (Ndufb6, ND1, and Cox4) in the inner membrane. This was due to a lack of YME1L proteolytic activity, since the excessive accumulation of subunits was reversed by overexpression of wild-type YME1L but not a proteolytically inactive YME1L variant. Similarly, the expression of wild-type YME1L restored the lamellar cristae morphology of YME1L-deficient mitochondria. Our results demonstrate the importance of mitochondrial inner-membrane proteostasis to both mitochondrial and cellular function and integrity and reveal a novel role for YME1L in the proteolytic regulation of respiratory chain biogenesis.

scholarly journals Mitochondrial inner membrane protein, Mic60/mitofilin in mammalian organ protection

2018 ◽  
Vol 234 (4) ◽  
pp. 3383-3393 ◽  
Author(s):  
Yansheng Feng ◽  
Ngonidzashe B. Madungwe ◽  
Jean C. Bopassa
Keyword(s):  
Membrane Protein ◽  
Organ Protection ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein

scholarly journals Identification of the essential yeast protein MIM17, an integral mitochondrial inner membrane protein involved in protein import

FEBS Letters ◽  
1994 ◽  
Vol 349 (2) ◽  
pp. 215-221 ◽  
Author(s):  
Ammy C. Maarse ◽  
Jolanda Blom ◽  
Petra Keil ◽  
Nikolaus Pfanner ◽  
Michiel Meijer
Keyword(s):  
Membrane Protein ◽  
Protein Import ◽  
Yeast Protein ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein

Reconstitution of the mitochondrial inner membrane protein Cox10 by using inteins

Mitochondrion ◽  
2011 ◽  
Vol 11 (4) ◽  
pp. 677
Author(s):  
R. Marco-Lázaro⁎ ◽  
A. Pérez-Martos ◽  
P. Fernández-Silva ◽  
J.A. Enriquez
Keyword(s):  
Membrane Protein ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein

Increased Expression of Mitochondrial Inner-Membrane Protein Mpv17 After Intracerebral Hemorrhage in Adult Rats

2015 ◽  
Vol 40 (8) ◽  
pp. 1620-1630 ◽  
Author(s):  
Aihong Li ◽  
Lei Li ◽  
Xiaolei Sun ◽  
Yaohui Ni ◽  
Xin Chen ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Intracerebral Hemorrhage ◽  
Adult Rats ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein

scholarly journals SMS1, a high-copy suppressor of the yeast mas6 mutant, encodes an essential inner membrane protein required for mitochondrial protein import.

1994 ◽  
Vol 5 (5) ◽  
pp. 529-538 ◽  
Author(s):  
K R Ryan ◽  
M M Menold ◽  
S Garrett ◽  
R E Jensen
Keyword(s):  
Membrane Protein ◽  
Protein Import ◽  
Mitochondrial Protein ◽  
Mitochondrial Protein Import ◽  
Yeast Saccharomyces Cerevisiae ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein ◽  
Membrane Spanning ◽  
Membrane Spanning Domains

MAS6 encodes an essential inner membrane protein required for mitochondrial protein import in the yeast Saccharomyces cerevisiae (Emtage and Jensen, 1993). To identify new inner membrane import components, we isolated a high-copy suppressor (SMS1) of the mas6-1 mutant. SMS1 encodes a 16.5-kDa protein that contains several potential membrane-spanning domains. The Sms1 protein is homologous to the carboxyl-terminal domain of the Mas6 protein. Like Mas6p, Sms1p is located in the mitochondrial inner membrane and is an essential protein. Depletion of Sms1p from cells causes defects in the import of several mitochondrial precursor proteins, suggesting that Sms1p is a new inner membrane import component. Our observations raise the possibility that Sms1p and Mas6p act together to translocate proteins across the inner membrane.

Sign in / Sign up

Export Citation Format

Share Document