AAA proteases with catalytic sites on opposite membrane surfaces comprise a proteolytic system for the ATP-dependent degradation of inner membrane proteins in mitochondria.

1996 ◽  
Vol 15 (16) ◽  
pp. 4218-4229 ◽  
Author(s):  
K. Leonhard ◽  
J. M. Herrmann ◽  
R. A. Stuart ◽  
G. Mannhaupt ◽  
W. Neupert ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Proteolytic System ◽  
Inner Membrane ◽  
Membrane Surfaces ◽  
Catalytic Sites

AAA proteases of mitochondria: quality control of membrane proteins and regulatory functions during mitochondrial biogenesis

2001 ◽  
Vol 29 (4) ◽  
pp. 431-436 ◽  
Author(s):  
T. Langer ◽  
M. Käser ◽  
C. Klanner ◽  
K. Leonhard
Keyword(s):  
Quality Control ◽  
Membrane Proteins ◽  
Matrix Space ◽  
Inner Membrane ◽  
Membrane Surfaces ◽  
Mitochondrial Inner Membrane ◽  
Catalytic Sites ◽  
The Matrix ◽  
The Stability ◽  
Regulatory Functions

An ubiquitous and conserved proteolytic system regulates the stability of mitochondrial inner membrane proteins. Two AAA proteases with catalytic sites at opposite membrane surfaces form a membrane-integrated quality control system and exert crucial functions during the biogenesis of mitochondria. Their activity is modulated by another membrane-protein complex that is composed of prohibitins. Peptides generated upon proteolysis in the matrix space are transported across the inner membrane by an ATP-binding cassette transporter. The function of these conserved components is discussed in the present review.

scholarly journals MAP-1 and IAP-1, Two Novel AAA Proteases with Catalytic Sites on Opposite Membrane Surfaces in Mitochondrial Inner Membrane ofNeurospora crassa

2001 ◽  
Vol 12 (9) ◽  
pp. 2858-2869 ◽  
Author(s):  
Carola Klanner ◽  
Holger Prokisch ◽  
Thomas Langer
Keyword(s):  
Matrix Space ◽  
Yeast Saccharomyces Cerevisiae ◽  
Inner Membrane ◽  
Functional Conservation ◽  
Membrane Surfaces ◽  
Mitochondrial Inner Membrane ◽  
Catalytic Sites ◽  
The Matrix ◽  
Inner Membrane Protein ◽  
Yeast Homolog

Eukaryotic AAA proteases form a conserved family of membrane-embedded ATP-dependent proteases but have been analyzed functionally only in the yeast Saccharomyces cerevisiae. Here, we have identified two novel members of this protein family in the filamentous fungus Neurospora crassa, which were termed MAP-1 and IAP-1. Both proteins are localized to the inner membrane of mitochondria. They are part of two similar-sized high molecular mass complexes, but expose their catalytic sites to opposite membrane surfaces, namely, the intermembrane and the matrix space. Disruption of iap-1 by repeat-induced point mutation caused a slow growth phenotype at high temperature and stabilization of a misfolded inner membrane protein against degradation. IAP-1 could partially substitute for functions of its yeast homolog Yme1, demonstrating functional conservation. However, respiratory growth at 37°C was not restored. Our results identify two components of the quality control system of the mitochondrial inner membrane in N. crassa and suggest that AAA proteases with catalytic sites exposed to opposite membrane surfaces are present in mitochondria of all eukaryotic cells.

scholarly journals Prohibitins Regulate Membrane Protein Degradation by the m-AAA Protease in Mitochondria

1999 ◽  
Vol 19 (5) ◽  
pp. 3435-3442 ◽  
Author(s):  
Gregor Steglich ◽  
Walter Neupert ◽  
Thomas Langer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Growth ◽  
Membrane Proteins ◽  
Eukaryotic Cells ◽  
Mitochondrial Morphology ◽  
Regulatory Effect ◽  
Inner Membrane ◽  
Functional Activities ◽  
Native Molecular Mass ◽  
Affect Cell Growth

ABSTRACT Prohibitins comprise a protein family in eukaryotic cells with potential roles in senescence and tumor suppression. Phb1p and Phb2p, members of the prohibitin family in Saccharomyces cerevisiae, have been implicated in the regulation of the replicative life span of the cells and in the maintenance of mitochondrial morphology. The functional activities of these proteins, however, have not been elucidated. We demonstrate here that prohibitins regulate the turnover of membrane proteins by the m-AAA protease, a conserved ATP-dependent protease in the inner membrane of mitochondria. The m-AAA protease is composed of the homologous subunits Yta10p (Afg3p) and Yta12p (Rca1p). Deletion ofPHB1 or PHB2 impairs growth of Δyta10 or Δyta12 cells but does not affect cell growth in the presence of the m-AAA protease. A prohibitin complex with a native molecular mass of approximately 2 MDa containing Phb1p and Phb2p forms a supercomplex with them-AAA protease. Proteolysis of nonassembled inner membrane proteins by the m-AAA protease is accelerated in mitochondria lacking Phb1p or Phb2p, indicating a negative regulatory effect of prohibitins on m-AAA protease activity. These results functionally link members of two conserved protein families in eukaryotes to the degradation of membrane proteins in mitochondria.

scholarly journals Fmp30, Mdm31, and Mdm32 Function in Ups1-Independent Cardiolipin Accumulation Under Low Phosphatidylethanolamine Conditions

Contact ◽  
2018 ◽  
Vol 1 ◽  
pp. 251525641876404
Author(s):  
Non Miyata ◽  
Osamu Kuge
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Proteins ◽  
Phosphatidic Acid ◽  
Yeast Saccharomyces Cerevisiae ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Per Se

Maintenance of the cardiolipin (CL) level largely depends on Ups1-Mdm35 complex-mediated intramitochondrial phosphatidic acid transfer. In addition, the presence of an alternative CL accumulation pathway has been suggested in the yeast Saccharomyces cerevisiae. This pathway is independent of the Ups1-Mdm35 complex and stimulated by loss of Ups2, which forms a complex with Mdm35 and mediates intramitochondrial transfer of phosphatidylserine for phosphatidylethanolamine synthesis. Recently, we found that the alternative CL accumulation pathway is enhanced by a lowered phosphatidylethanolamine level, not by loss of Ups2 per se, and depends on three mitochondrial inner membrane proteins, Fmp30, Mdm31, and Mdm32.

Translocation of mitochondrial inner-membrane proteins: conformation matters

2006 ◽  
Vol 31 (5) ◽  
pp. 259-267 ◽  
Author(s):  
Carine de Marcos-Lousa ◽  
Dionisia P Sideris ◽  
Kostas Tokatlidis
Keyword(s):  
Membrane Proteins ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane
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