scholarly journals Role of positively charged transmembrane segments in the insertion and assembly of mitochondrial inner-membrane proteins

2001 ◽  
Vol 98 (24) ◽  
pp. 13814-13819 ◽  
Author(s):  
Y. Saint-Georges ◽  
P. Hamel ◽  
C. Lemaire ◽  
G. Dujardin
Keyword(s):  
Membrane Proteins ◽  
Inner Membrane ◽  
Transmembrane Segments ◽  
Mitochondrial Inner Membrane ◽  
Positively Charged

scholarly journals Mitochondrial Membrane Dynamics—Functional Positioning of OPA1

Antioxidants ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 186 ◽  
Author(s):  
Hakjoo Lee ◽  
Yisang Yoon
Keyword(s):  
Mitochondrial Membrane ◽  
Proteolytic Cleavage ◽  
Membrane Dynamics ◽  
Mitochondrial Morphology ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Functional Differences ◽  
New Information ◽  
New Development

The maintenance of mitochondrial energetics requires the proper regulation of mitochondrial morphology, and vice versa. Mitochondrial dynamins control mitochondrial morphology by mediating fission and fusion. One of them, optic atrophy 1 (OPA1), is the mitochondrial inner membrane remodeling protein. OPA1 has a dual role in maintaining mitochondrial morphology and energetics through mediating inner membrane fusion and maintaining the cristae structure. OPA1 is expressed in multiple variant forms through alternative splicing and post-translational proteolytic cleavage, but the functional differences between these variants have not been completely understood. Recent studies generated new information regarding the role of OPA1 cleavage. In this review, we will first provide a brief overview of mitochondrial membrane dynamics by describing fission and fusion that are mediated by mitochondrial dynamins. The second part describes OPA1-mediated fusion and energetic maintenance, the role of OPA1 cleavage, and a new development in OPA1 function, in which we will provide new insight for what OPA1 does and what proteolytic cleavage of OPA1 is for.

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.

scholarly journals Role of mitochondrial inner membrane organizing system in protein biogenesis of the mitochondrial outer membrane

2012 ◽  
Vol 23 (20) ◽  
pp. 3948-3956 ◽  
Author(s):  
Maria Bohnert ◽  
Lena-Sophie Wenz ◽  
Ralf M. Zerbes ◽  
Susanne E. Horvath ◽  
David A. Stroud ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Early Stage ◽  
Outer Membrane Proteins ◽  
Mitochondrial Outer Membrane ◽  
Large Core ◽  
Large Protein ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Protein Biogenesis

Mitochondria contain two membranes, the outer membrane and the inner membrane with folded cristae. The mitochondrial inner membrane organizing system (MINOS) is a large protein complex required for maintaining inner membrane architecture. MINOS interacts with both preprotein transport machineries of the outer membrane, the translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). It is unknown, however, whether MINOS plays a role in the biogenesis of outer membrane proteins. We have dissected the interaction of MINOS with TOM and SAM and report that MINOS binds to both translocases independently. MINOS binds to the SAM complex via the conserved polypeptide transport–associated domain of Sam50. Mitochondria lacking mitofilin, the large core subunit of MINOS, are impaired in the biogenesis of β-barrel proteins of the outer membrane, whereas mutant mitochondria lacking any of the other five MINOS subunits import β-barrel proteins in a manner similar to wild-type mitochondria. We show that mitofilin is required at an early stage of β-barrel biogenesis that includes the initial translocation through the TOM complex. We conclude that MINOS interacts with TOM and SAM independently and that the core subunit mitofilin is involved in biogenesis of outer membrane β-barrel proteins.

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

scholarly journals The J-related Segment of Tim44 Is Essential for Cell Viability: A Mutant Tim44 Remains in the Mitochondrial Import Site, but Inefficiently Recruits mtHsp70 and Impairs Protein Translocation

1999 ◽  
Vol 145 (5) ◽  
pp. 961-972 ◽  
Author(s):  
Alessio Merlin ◽  
Wolfgang Voos ◽  
Ammy C. Maarse ◽  
Michiel Meijer ◽  
Nikolaus Pfanner ◽  
...  
Keyword(s):  
Protein Import ◽  
Protein Translocation ◽  
Adaptor Protein ◽  
Dependent Manner ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
J Proteins

Tim44 is a protein of the mitochondrial inner membrane and serves as an adaptor protein for mtHsp70 that drives the import of preproteins in an ATP-dependent manner. In this study we have modified the interaction of Tim44 with mtHsp70 and characterized the consequences for protein translocation. By deletion of an 18-residue segment of Tim44 with limited similarity to J-proteins, the binding of Tim44 to mtHsp70 was weakened. We found that in the yeast Saccharomyces cerevisiae the deletion of this segment is lethal. To investigate the role of the 18-residue segment, we expressed Tim44Δ18 in addition to the endogenous wild-type Tim44. Tim44Δ18 is correctly targeted to mitochondria and assembles in the inner membrane import site. The coexpression of Tim44Δ18 together with wild-type Tim44, however, does not stimulate protein import, but reduces its efficiency. In particular, the promotion of unfolding of preproteins during translocation is inhibited. mtHsp70 is still able to bind to Tim44Δ18 in an ATP-regulated manner, but the efficiency of interaction is reduced. These results suggest that the J-related segment of Tim44 is needed for productive interaction with mtHsp70. The efficient cooperation of mtHsp70 with Tim44 facilitates the translocation of loosely folded preproteins and plays a crucial role in the import of preproteins which contain a tightly folded domain.

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.

Functional role of positively charged amino acid residues in the transmembrane segments of the yeast PMA1 ATPase

1998 ◽  
Vol 43 (2) ◽  
pp. 208-210 ◽  
Author(s):  
K. P. Padmanabha ◽  
V. V. Petrov ◽  
C. W. Slayman
Keyword(s):  
Amino Acid ◽  
Functional Role ◽  
Amino Acid Residues ◽  
Transmembrane Segments ◽  
Positively Charged

scholarly journals Role of the translocase of the mitochondrial inner membrane in the import of tRNAs into mitochondria in Trypanosoma brucei

Gene ◽  
2020 ◽  
Vol 748 ◽  
pp. 144705
Author(s):  
Muhammad Younas Khan Barozai ◽  
Minu Chaudhuri
Keyword(s):  
Trypanosoma Brucei ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane
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