scholarly journals Fusion proteins containing the cytochrome b2 presequence are sorted to the mitochondrial intermembrane space independently of hsp60.

1994 ◽  
Vol 269 (25) ◽  
pp. 17279-17288
Author(s):  
S. Rospert ◽  
S. Müller ◽  
G. Schatz ◽  
B.S. Glick
2014 ◽  
Vol 55 (2) ◽  
pp. 332-341 ◽  
Author(s):  
Victoria Hung ◽  
Peng Zou ◽  
Hyun-Woo Rhee ◽  
Namrata D. Udeshi ◽  
Valentin Cracan ◽  
...  

1993 ◽  
Vol 123 (1) ◽  
pp. 119-126 ◽  
Author(s):  
W Voos ◽  
B D Gambill ◽  
B Guiard ◽  
N Pfanner ◽  
E A Craig

To test the hypothesis that 70-kD mitochondrial heat shock protein (mt-hsp70) has a dual role in membrane translocation of preproteins we screened preproteins in an attempt to find examples which required either only the unfoldase or only the translocase function of mt-hsp70. We found that a series of fusion proteins containing amino-terminal portions of the intermembrane space protein cytochrome b2 (cyt. b2) fused to dihydrofolate reductase (DHFR) were differentially imported into mitochondria containing mutant hsp70s. A fusion protein between the amino-terminal 167 residues of the precursor of cyt. b2 and DHFR was efficiently transported into mitochondria independently of both hsp70 functions. When the length of the cyt. b2 portion was increased and included the heme binding domain, the fusion protein became dependent on the unfoldase function of mt-hsp70, presumably caused by a conformational restriction of the heme-bound preprotein. In the absence of heme the noncovalent heme binding domain in the longer fusion proteins no longer conferred a dependence on the unfoldase function. When the cyt. b2 portion of the fusion protein was less than 167 residues, its import was still independent of mt-hsp70 function; however, deletion of the intermembrane space sorting signal resulted in preproteins that ended up in the matrix of wild-type mitochondria and whose translocation was strictly dependent on the translocase function of mt-hsp70. These findings provide strong evidence for a dual role of mt-hsp70 in membrane translocation and indicate that preproteins with an intermembrane space sorting signal can be correctly imported even in mutants with severely impaired hsp70 function.


2014 ◽  
Vol 289 (14) ◽  
pp. 9852-9864 ◽  
Author(s):  
Hugo Fraga ◽  
Joan-Josep Bech-Serra ◽  
Francesc Canals ◽  
Gabriel Ortega ◽  
Oscar Millet ◽  
...  

1998 ◽  
Vol 265 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Heiko Martin ◽  
Christoph Eckerskorn ◽  
Frank Gärtner ◽  
Joachim Rassow ◽  
Fritz Lottspeich ◽  
...  

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Andrea Pasquadibisceglie ◽  
Fabio Polticelli

Abstract The members of the mitochondrial carrier family, also known as solute carrier family 25 (SLC25), are transmembrane proteins involved in the translocation of a plethora of small molecules between the mitochondrial intermembrane space and the matrix. These transporters are characterized by three homologous domains structure and a transport mechanism that involves the transition between different conformations. Mutations in regions critical for these transporters’ function often cause several diseases, given the crucial role of these proteins in the mitochondrial homeostasis. Experimental studies can be problematic in the case of membrane proteins, in particular concerning the characterization of the structure–function relationships. For this reason, computational methods are often applied in order to develop new hypotheses or to support/explain experimental evidence. Here the computational analyses carried out on the SLC25 members are reviewed, describing the main techniques used and the outcome in terms of improved knowledge of the transport mechanism. Potential future applications on this protein family of more recent and advanced in silico methods are also suggested.


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