Phylogeny and expression of the secA gene from a chromophytic alga - implications for the evolution of plastids and sec-dependent protein translocation

1997 ◽  
Vol 32 (4) ◽  
pp. 300-307 ◽  
Author(s):  
Klaus Valentin
Keyword(s):  
Protein Translocation ◽  
Seca Gene ◽  
Dependent Protein ◽  
Chromophytic Alga

scholarly journals Genetic Analysis of Pathway Specificity during Posttranslational Protein Translocation across the Escherichia coli Plasma Membrane

2003 ◽  
Vol 185 (9) ◽  
pp. 2811-2819 ◽  
Author(s):  
Natascha Blaudeck ◽  
Peter Kreutzenbeck ◽  
Roland Freudl ◽  
Georg A. Sprenger
Keyword(s):  
Escherichia Coli ◽  
Signal Peptide ◽  
Protein Translocation ◽  
Alternative Possibilities ◽  
Amino Acid Residues ◽  
Sec Pathway ◽  
Twin Arginine Translocation ◽  
Tat Pathway ◽  
Arginine Residues ◽  
Dependent Protein

ABSTRACT In Escherichia coli, the SecB/SecA branch of the Sec pathway and the twin-arginine translocation (Tat) pathway represent two alternative possibilities for posttranslational translocation of proteins across the cytoplasmic membrane. Maintenance of pathway specificity was analyzed using a model precursor consisting of the mature part of the SecB-dependent maltose-binding protein (MalE) fused to the signal peptide of the Tat-dependent TorA protein. The TorA signal peptide selectively and specifically directed MalE into the Tat pathway. The characterization of a spontaneous TorA signal peptide mutant (TorA*), in which the two arginine residues in the c-region had been replaced by one leucine residue, showed that the TorA*-MalE mutant precursor had acquired the ability for efficiently using the SecB/SecA pathway. Despite the lack of the “Sec avoidance signal,” the mutant precursor was still capable of using the Tat pathway, provided that the kinetically favored Sec pathway was blocked. These results show that the h-region of the TorA signal peptide is, in principle, sufficiently hydrophobic for Sec-dependent protein translocation, and therefore, the positively charged amino acid residues in the c-region represent a major determinant for Tat pathway specificity. Tat-dependent export of TorA-MalE was significantly slower in the presence of SecB than in its absence, showing that SecB can bind to this precursor despite the presence of the Sec avoidance signal in the c-region of the TorA signal peptide, strongly suggesting that the function of the Sec avoidance signal is not the prevention of SecB binding; rather, it must be exerted at a later step in the Sec pathway.

scholarly journals A β-Lactamase Based Reporter System for ESX Dependent Protein Translocation in Mycobacteria

PLoS ONE ◽  
2012 ◽  
Vol 7 (4) ◽  
pp. e35453 ◽  
Author(s):  
Tobias Rosenberger ◽  
Juliane K. Brülle ◽  
Peter Sander
Keyword(s):  
Protein Translocation ◽  
Reporter System ◽  
Dependent Protein

scholarly journals Protein import into mitochondria: ATP-dependent protein translocation activity in a submitochondrial fraction enriched in membrane contact sites and specific proteins.

1989 ◽  
Vol 109 (6) ◽  
pp. 2603-2616 ◽  
Author(s):  
L Pon ◽  
T Moll ◽  
D Vestweber ◽  
B Marshallsay ◽  
G Schatz
Keyword(s):  
Protein Import ◽  
Protein Translocation ◽  
Buoyant Density ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Mitochondrial Membranes ◽  
Outer Membranes ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Dependent Protein

To identify the membrane regions through which yeast mitochondria import proteins from the cytoplasm, we have tagged these regions with two different partly translocated precursor proteins. One of these was bound to the mitochondrial surface of ATP-depleted mitochondria and could subsequently be chased into mitochondria upon addition of ATP. The other intermediate was irreversibly stuck across both mitochondrial membranes at protein import sites. Upon subfraction of the mitochondria, both intermediates cofractionated with membrane vesicles whose buoyant density was between that of inner and outer membranes. When these vesicles were prepared from mitochondria containing the chaseable intermediate, they internalized it upon addition of ATP. A non-hydrolyzable ATP analogue was inactive. This vesicle fraction contained closed, right-side-out inner membrane vesicles attached to leaky outer membrane vesicles. The vesicles contained the mitochondrial binding sites for cytoplasmic ribosomes and contained several mitochondrial proteins that were enriched relative to markers of inner or outer membranes. By immunoelectron microscopy, two of these proteins were concentrated at sites where mitochondrial inner and outer membranes are closely apposed. We conclude that these vesicles contain contact sites between the two mitochondrial membranes, that these sites are the entry point for proteins into mitochondria, and that the isolated vesicles are still translocation competent.

scholarly journals Routing of Hansenula polymorpha Alcohol Oxidase: An Alternative Peroxisomal Protein-sorting Machinery

2004 ◽  
Vol 15 (3) ◽  
pp. 1347-1355 ◽  
Author(s):  
Katja Gunkel ◽  
Ralf van Dijk ◽  
Marten Veenhuis ◽  
Ida J. van der Klei
Keyword(s):  
Amino Acids ◽  
Protein Translocation ◽  
Hansenula Polymorpha ◽  
Alcohol Oxidase ◽  
N Terminus ◽  
Dependent Protein ◽  
Peptides Synthesis ◽  
Translocation Pathway ◽  
Tpr Domain ◽  
Fad Binding

Import of Hansenula polymorpha alcohol oxidase (AO) into peroxisomes is dependent on the PTS1 receptor, HpPex5p. The PTS1 of AO (-LARF) is sufficient to direct reporter proteins to peroxisomes. To study AO sorting in more detail, strains producing mutant AO proteins were constructed. AO containing a mutation in the FAD binding fold was mislocalized to the cytosol. This indicates that the PTS1 of AO is not sufficient for import of AO. AO protein in which the PTS1 was destroyed (-LARA) was normally sorted to peroxisomes. Moreover, C-terminal deletions of up to 16 amino acids did not significantly affect AO import, indicating that the PTS1 was not necessary for targeting. Consistent with these observations we found that AO import occurred independent from the C-terminal TPR-domain of HpPex5p, known to bind PTS1 peptides. Synthesis of the N-terminal domain (amino acids 1-272) of HpPex5p in pex5 cells restored AO import, whereas other PTS1 proteins were mislocalized to the cytosol. These data indicate that AO is imported via a novel HpPex5p-dependent protein translocation pathway, which does not require the PTS1 of AO and the C-terminal TPR domains of HpPex5p, but involves FAD binding and the N-terminus of HpPex5p.

scholarly journals Involvement of PpiD in Sec-dependent protein translocation

2018 ◽  
Vol 1865 (2) ◽  
pp. 273-280 ◽  
Author(s):  
Michaela Fürst ◽  
Yufan Zhou ◽  
Jana Merfort ◽  
Matthias Müller
Keyword(s):  
Protein Translocation ◽  
Dependent Protein

scholarly journals Additional In Vitro and In Vivo Evidence for SecA Functioning as Dimers in the Membrane: Dissociation into Monomers Is Not Essential for Protein Translocation in Escherichia coli

2007 ◽  
Vol 190 (4) ◽  
pp. 1413-1418 ◽  
Author(s):  
Hongyun Wang ◽  
Bing Na ◽  
Hsiuchin Yang ◽  
Phang C. Tai
Keyword(s):  
Escherichia Coli ◽  
Lipid Bilayers ◽  
Cytoplasmic Membrane ◽  
Protein Translocation ◽  
Secretory Proteins ◽  
Oligomeric State ◽  
Dependent Protein ◽  
Ts Mutant

ABSTRACT SecA is an essential component in the Sec-dependent protein translocation pathway and, together with ATP, provides the driving force for the transport of secretory proteins across the cytoplasmic membrane of Escherichia coli. Previous studies established that SecA undergoes monomer-dimer equilibrium in solution. However, the oligomeric state of functional SecA during the protein translocation process is controversial. In this study, we provide additional evidence that SecA functions as a dimer in the membrane by (i) demonstration of the capability of the presumably monomeric SecA derivative to be cross-linked as dimers in vitro and in vivo, (ii) complementation of the growth of a secA(Ts) mutant with another nonfunctional SecA or (iii) in vivo complementation and in vitro function of a genetically tandem SecA dimer that does not dissociate into monomers, and (iv) formation of similar ring-like structures by the tandem SecA dimer and SecA in the presence of lipid bilayers. We conclude that SecA functions as a dimer in the membrane and dissociation into monomers is not necessary during protein translocation.

Charged Amino Acids in a Preprotein Inhibit SecA-Dependent Protein Translocation

2009 ◽  
Vol 386 (4) ◽  
pp. 1000-1010 ◽  
Author(s):  
Nico Nouwen ◽  
Greetje Berrelkamp ◽  
Arnold J.M. Driessen
Keyword(s):  
Amino Acids ◽  
Protein Translocation ◽  
Charged Amino Acids ◽  
Dependent Protein
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