scholarly journals An internal region of the peroxisomal membrane protein PMP47 is essential for sorting to peroxisomes

1994 ◽  
Vol 124 (6) ◽  
pp. 915-925 ◽  
Author(s):  
MT McCammon ◽  
JA McNew ◽  
PJ Willy ◽  
JM Goodman
Keyword(s):  
Amino Acids ◽  
Sequence Similarity ◽  
Candida Boidinii ◽  
Carrier Proteins ◽  
Peroxisomal Membrane ◽  
Lower Efficiency ◽  
Mitochondrial Carrier ◽  
Peroxisomal Targeting ◽  
Membrane Spanning ◽  
Mitochondrial Carrier Proteins

Targeting sequences on peroxisomal membrane proteins have not yet been identified. We have attempted to find such a sequence within PMP47, a protein of the methylotrophic yeast, Candida boidinii. This protein of 423 amino acids shows sequence similarity with proteins in the family of mitochondrial carrier proteins. As such, it is predicted to have six membrane-spanning domains. Protease susceptibility experiments are consistent with a six-membrane-spanning model for PMP47, although the topology for the peroxisomal protein is inverted compared with the mitochondrial carrier proteins. PMP47 contains two potential peroxisomal targeting sequences (PTS1), an internal SKL (residues 320-322) and a carboxy terminal AKE (residues 421-423). Using a heterologous in vivo sorting system, we show that efficient sorting occurs in the absence of both sequences. Analysis of PMP47-dihydrofolate reductase (DHFR) fusion proteins revealed that amino acids 1-199 of PMP47, which contain the first three putative membrane spans, do not contain the necessary targeting information, whereas a fusion with amino acids 1-267, which contains five spans, is fully competent for sorting to peroxisomes. Similarly, a DHFR fusion construct containing residues 268-423 did not target to peroxisomes while residues 203-420 appeared to sort to that organelle, albeit at lower efficiency than the 1-267 construct. However, DHFR constructs containing only amino acids 185-267 or 203-267 of PMP47 were not found to be associated with peroxisomes. We conclude that amino acids 199-267 are necessary for peroxisomal targeting, although additional sequences may be required for efficient sorting to, or retention by, the organelles.

scholarly journals Presence of a Member of the Mitochondrial Carrier Family in Hydrogenosomes: Conservation of Membrane-Targeting Pathways between Hydrogenosomes and Mitochondria

2000 ◽  
Vol 20 (7) ◽  
pp. 2488-2497 ◽  
Author(s):  
Sabrina D. Dyall ◽  
Carla M. Koehler ◽  
Maria G. Delgadillo-Correa ◽  
Peter J. Bradley ◽  
Evelyn Plümper ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Protein Targeting ◽  
Phylogenetic Analyses ◽  
Eukaryotic Cell ◽  
Membrane Targeting ◽  
Carrier Proteins ◽  
Mitochondrial Carrier ◽  
Mitochondrial Carrier Family ◽  
Targeting Signal ◽  
Mitochondrial Carrier Proteins

ABSTRACT A number of microaerophilic eukaryotes lack mitochondria but possess another organelle involved in energy metabolism, the hydrogenosome. Limited phylogenetic analyses of nuclear genes support a common origin for these two organelles. We have identified a protein of the mitochondrial carrier family in the hydrogenosome ofTrichomonas vaginalis and have shown that this protein, Hmp31, is phylogenetically related to the mitochondrial ADP-ATP carrier (AAC). We demonstrate that the hydrogenosomal AAC can be targeted to the inner membrane of mitochondria isolated from Saccharomyces cerevisiae through the Tim9-Tim10 import pathway used for the assembly of mitochondrial carrier proteins. Conversely, yeast mitochondrial AAC can be targeted into the membranes of hydrogenosomes. The hydrogenosomal AAC contains a cleavable, N-terminal presequence; however, this sequence is not necessary for targeting the protein to the organelle. These data indicate that the membrane-targeting signal(s) for hydrogenosomal AAC is internal, similar to that found for mitochondrial carrier proteins. Our findings indicate that the membrane carriers and membrane protein-targeting machinery of hydrogenosomes and mitochondria have a common evolutionary origin. Together, they provide strong evidence that a single endosymbiont evolved into a progenitor organelle in early eukaryotic cells that ultimately give rise to these two distinct organelles and support the hydrogen hypothesis for the origin of the eukaryotic cell.

scholarly journals The peroxin Pex17p of the yeast Yarrowia lipolytica is associated peripherally with the peroxisomal membrane and is required for the import of a subset of matrix proteins.

1997 ◽  
Vol 17 (5) ◽  
pp. 2511-2520 ◽  
Author(s):  
J J Smith ◽  
R K Szilard ◽  
M Marelli ◽  
R A Rachubinski
Keyword(s):  
Amino Acids ◽  
Oleic Acid ◽  
Yarrowia Lipolytica ◽  
Matrix Proteins ◽  
Peroxisomal Membrane ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Carboxyl Terminal ◽  
Peroxisomal Targeting Signal ◽  
Yeast Yarrowia Lipolytica

PEX genes encode peroxins, which are required for the biogenesis of peroxisomes. The Yarrowia lipolytica PEX17 gene encodes the peroxin Pex17p, which is 671 amino acids in length and has a predicted molecular mass of 75,588 Da. Pex17p is peripherally associated with the peroxisomal membrane. The carboxyl-terminal tripeptide, Gly-Thr-Leu, of Pex17p is not necessary for its targeting to peroxisomes. Synthesis of Pex17p is low in cells grown in glucose-containing medium and increases after the cells are shifted to oleic acid-containing medium. Cells of the pex17-1 mutant, the original mutant strain, and the pex17-KA mutant, a strain in which most of the PEX17 gene is deleted, fail to form normal peroxisomes but instead contain numerous large, multimembraned structures. The import of peroxisomal matrix proteins in these mutants is selectively impaired. This selective import is not a function of the nature of the peroxisomal targeting signal. We suggest a regulatory role for Pex17p in the import of a subset of matrix proteins into peroxisomes.

scholarly journals Pex17p of Saccharomyces cerevisiae Is a Novel Peroxin and Component of the Peroxisomal Protein Translocation Machinery

1998 ◽  
Vol 140 (1) ◽  
pp. 49-60 ◽  
Author(s):  
Bettina Huhse ◽  
Peter Rehling ◽  
Markus Albertini ◽  
Lars Blank ◽  
Karl Meller ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Translocation ◽  
Coiled Coil ◽  
Matrix Proteins ◽  
Peroxisomal Membrane ◽  
Trimeric Complex ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Membrane Spanning ◽  
Mutant Cells

The Saccharomyces cerevisiae pex17-1 mutant was isolated from a screen to identify mutants defective in peroxisome biogenesis. pex17-1 and pex17 null mutants fail to import matrix proteins into peroxisomes via both PTS1- and PTS2-dependent pathways. The PEX17 gene (formerly PAS9; Albertini, M., P. Rehling, R. Erdmann, W. Girzalsky, J.A.K.W. Kiel, M. Veenhuis, and W.-H Kunau. 1997. Cell. 89:83–92) encodes a polypeptide of 199 amino acids with one predicted membrane spanning region and two putative coiled-coil structures. However, localization studies demonstrate that Pex17p is a peripheral membrane protein located at the surface of peroxisomes. Particulate structures containing the peroxisomal integral membrane proteins Pex3p and Pex11p are evident in pex17 mutant cells, indicating the existence of peroxisomal remnants (“ghosts”). This finding suggests that pex17 null mutant cells are not impaired in peroxisomal membrane biogenesis. Two-hybrid studies showed that Pex17p directly binds to Pex14p, the recently proposed point of convergence for the two peroxisomal targeting signal (PTS)-dependent import pathways, and indirectly to Pex5p, the PTS1 receptor. The latter interaction requires Pex14p, indicating the potential of these three peroxins to form a trimeric complex. This conclusion is supported by immunoprecipitation experiments showing that Pex14p and Pex17p coprecipitate with both PTS receptors in the absence of Pex13p. From these and other studies we conclude that Pex17p, in addition to Pex13p and Pex14p, is the third identified component of the peroxisomal translocation machinery.

scholarly journals Pmp27 promotes peroxisomal proliferation.

1995 ◽  
Vol 129 (2) ◽  
pp. 345-355 ◽  
Author(s):  
P A Marshall ◽  
Y I Krimkevich ◽  
R H Lark ◽  
J M Dyer ◽  
M Veenhuis ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Sequence Similarity ◽  
Carbon Sources ◽  
Weight Of Evidence ◽  
Candida Boidinii ◽  
Multicopy Plasmid ◽  
Wild Type ◽  
Beta Oxidation ◽  
Peroxisomal Membrane ◽  
A Cell

Peroxisomes perform many essential functions in eukaryotic cells. The weight of evidence indicates that these organelles divide by budding from preexisting peroxisomes. This process is not understood at the molecular level. Peroxisomal proliferation can be induced in Saccharomyces cerevisiae by oleate. This growth substrate is metabolized by peroxisomal enzymes. We have identified a protein, Pmp27, that promotes peroxisomal proliferation. This protein, previously termed Pmp24, was purified from peroxisomal membranes, and the corresponding gene, PMP27, was isolated and sequenced. Pmp27 shares sequence similarity with the Pmp30 family in Candida boidinii. Pmp27 is a hydrophobic peroxisomal membrane protein but it can be extracted by high pH, suggesting that it does not fully span the bilayer. Its expression is regulated by oleate. The function of Pmp27 was probed by observing the phenotype of strains in which the protein was eliminated by gene disruption or overproduced by expression from a multicopy plasmid. The strain containing the disruption (3B) was able to grow on all carbon sources tested, including oleate, although growth on oleate, glycerol, and acetate was slower than wild type. Strain 3B contained peroxisomes with all of the enzymes of beta-oxidation. However, in addition to the presence of a few modestly sized peroxisomes seen in a typical thin section of a cell growing on oleate-containing medium, cells of strain 3B also contained one or two very large peroxisomes. In contrast, cells in a strain in which Pmp27 was overexpressed contained an increased number of normal-sized peroxisomes. We suggest that Pmp27 promotes peroxisomal proliferation by participating in peroxisomal elongation or fission.

scholarly journals Arabidopsis calcium-binding mitochondrial carrier proteins as potential facilitators of mitochondrial ATP-import and plastid SAM-import

FEBS Letters ◽  
2011 ◽  
Vol 585 (24) ◽  
pp. 3935-3940 ◽  
Author(s):  
Simon Stael ◽  
Agostinho G. Rocha ◽  
Alan J. Robinson ◽  
Przemyslaw Kmiecik ◽  
Ute C. Vothknecht ◽  
...  
Keyword(s):  
Calcium Binding ◽  
Carrier Proteins ◽  
Mitochondrial Carrier ◽  
Mitochondrial Carrier Proteins
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