scholarly journals A Transcriptomic and Proteomic Characterization of the Arabidopsis Mitochondrial Protein Import Apparatus and Its Response to Mitochondrial Dysfunction

2004 ◽  
Vol 134 (2) ◽  
pp. 777-789 ◽  
Author(s):  
Ryan Lister ◽  
Orinda Chew ◽  
May-Nee Lee ◽  
Joshua L. Heazlewood ◽  
Rachel Clifton ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
Protein Import ◽  
Mitochondrial Protein ◽  
Mitochondrial Protein Import

scholarly journals Reversal of mitochondrial proteomic loss in Type 1 diabetic heart with overexpression of phospholipid hydroperoxide glutathione peroxidase

2013 ◽  
Vol 304 (7) ◽  
pp. R553-R565 ◽  
Author(s):  
Walter A. Baseler ◽  
Erinne R. Dabkowski ◽  
Rajaganapathi Jagannathan ◽  
Dharendra Thapa ◽  
Cody E. Nichols ◽  
...  
Keyword(s):  
Glutathione Peroxidase ◽  
Mitochondrial Dysfunction ◽  
Protein Import ◽  
Contractile Function ◽  
Tricarboxylic Acid Cycle ◽  
Mitochondrial Protein ◽  
Diabetic Heart ◽  
Phospholipid Hydroperoxide Glutathione Peroxidase ◽  
Mitochondrial Protein Import ◽  
Phospholipid Hydroperoxide

Mitochondrial dysfunction is a contributor to diabetic cardiomyopathy. Previously, we observed proteomic decrements within the inner mitochondrial membrane (IMM) and matrix of diabetic cardiac interfibrillar mitochondria (IFM) correlating with dysfunctional mitochondrial protein import. The goal of this study was to determine whether overexpression of mitochondria phospholipid hydroperoxide glutathione peroxidase 4 (mPHGPx), an antioxidant enzyme capable of scavenging membrane-associated lipid peroxides in the IMM, could reverse proteomic alterations, dysfunctional protein import, and ultimately, mitochondrial dysfunction associated with the diabetic heart. MPHGPx transgenic mice and controls were made diabetic by multiple low-dose streptozotocin injections and examined after 5 wk of hyperglycemia. Five weeks after hyperglycemia onset, in vivo analysis of cardiac contractile function revealed decreased ejection fraction and fractional shortening in diabetic hearts that was reversed with mPHGPx overexpression. MPHGPx overexpression increased electron transport chain function while attenuating hydrogen peroxide production and lipid peroxidation in diabetic mPHGPx IFM. MPHGPx overexpression lessened proteomic loss observed in diabetic IFM. Posttranslational modifications, including oxidations and deamidations, were attenuated in diabetic IFM with mPHGPx overexpression. Mitochondrial protein import dysfunction in diabetic IFM was reversed with mPHGPx overexpression correlating with protein import constituent preservation. Ingenuity Pathway Analyses indicated that oxidative phosphorylation, tricarboxylic acid cycle, and fatty acid oxidation processes most influenced in diabetic IFM were preserved by mPHGPx overexpression. Specific mitochondrial networks preserved included complex I and II, mitochondrial ultrastructure, and mitochondrial protein import. These results indicate that mPHGPx overexpression can preserve the mitochondrial proteome and provide cardioprotective benefits to the diabetic heart.

Characterization of the Novel Mitochondrial Protein Import Component, Tom34, in Mammalian Cells

1999 ◽  
Vol 125 (4) ◽  
pp. 721-727 ◽  
Author(s):  
N. Chewawiwat ◽  
M. Yano ◽  
K. Terada ◽  
N. J Hoogenraad ◽  
M. Mori
Keyword(s):  
Mammalian Cells ◽  
Protein Import ◽  
Mitochondrial Protein ◽  
The Novel ◽  
Mitochondrial Protein Import

scholarly journals Characterization of Mmp37p, aSaccharomyces cerevisiaeMitochondrial Matrix Protein with a Role in Mitochondrial Protein Import

2006 ◽  
Vol 17 (9) ◽  
pp. 4051-4062 ◽  
Author(s):  
Michelle R. Gallas ◽  
Mary K. Dienhart ◽  
Rosemary A. Stuart ◽  
Roy M. Long
Keyword(s):  
Matrix Protein ◽  
Protein Import ◽  
Mitochondrial Protein ◽  
Temperature Sensitive ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Close Proximity ◽  
The Matrix ◽  
Targeting Signal

Many mitochondrial proteins are encoded by nuclear genes and after translation in the cytoplasm are imported via translocases in the outer and inner membranes, the TOM and TIM complexes, respectively. Here, we report the characterization of the mitochondrial protein, Mmp37p (YGR046w) and demonstrate its involvement in the process of protein import into mitochondria. Haploid cells deleted of MMP37 are viable but display a temperature-sensitive growth phenotype and are inviable in the absence of mitochondrial DNA. Mmp37p is located in the mitochondrial matrix where it is peripherally associated with the inner membrane. We show that Mmp37p has a role in the translocation of proteins across the mitochondrial inner membrane via the TIM23-PAM complex and further demonstrate that substrates containing a tightly folded domain in close proximity to their mitochondrial targeting sequences display a particular dependency on Mmp37p for mitochondrial import. Prior unfolding of the preprotein, or extension of the region between the targeting signal and the tightly folded domain, relieves their dependency for Mmp37p. Furthermore, evidence is presented to show that Mmp37 may affect the assembly state of the TIM23 complex. On the basis of these findings, we hypothesize that the presence of Mmp37p enhances the early stages of the TIM23 matrix import pathway to ensure engagement of incoming preproteins with the mtHsp70p/PAM complex, a step that is necessary to drive the unfolding and complete translocation of the preprotein into the matrix.

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