scholarly journals A Single Peroxisomal Targeting Signal Mediates Matrix Protein Import in Diatoms

PLoS ONE ◽  
2011 ◽  
Vol 6 (9) ◽  
pp. e25316 ◽  
Author(s):  
Nicola H. Gonzalez ◽  
Gregor Felsner ◽  
Frederic D. Schramm ◽  
Andreas Klingl ◽  
Uwe-G. Maier ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Protein Import ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Peroxisomal Targeting Signal

Metabolic control of peroxisome abundance

1999 ◽  
Vol 112 (10) ◽  
pp. 1579-1590 ◽  
Author(s):  
C.C. Chang ◽  
S. South ◽  
D. Warren ◽  
J. Jones ◽  
A.B. Moser ◽  
...  
Keyword(s):  
Metabolic Control ◽  
Matrix Protein ◽  
Protein Import ◽  
Zellweger Syndrome ◽  
Mutant Gene ◽  
Peroxisomal Membrane ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Complementation Groups ◽  
Peroxisomal Targeting Signal

Zellweger syndrome and related disorders represent a group of lethal, genetically heterogeneous diseases. These peroxisome biogenesis disorders (PBDs) are characterized by defective peroxisomal matrix protein import and comprise at least 10 complementation groups. The genes defective in seven of these groups and more than 90% of PBD patients are now known. Here we examine the distribution of peroxisomal membrane proteins in fibroblasts from PBD patients representing the seven complementation groups for which the mutant gene is known. Peroxisomes were detected in all PBD cells, indicating that the ability to form a minimal peroxisomal structure is not blocked in these mutants. We also observed that peroxisome abundance was reduced fivefold in PBD cells that are defective in the PEX1, PEX5, PEX12, PEX6, PEX10, and PEX2 genes. These cell lines all display a defect in the import of proteins with the type-1 peroxisomal targeting signal (PTS1). In contrast, peroxisome abundance was unaffected in cells that are mutated in PEX7 and are defective only in the import of proteins with the type-2 peroxisomal targeting signal. Interestingly, a fivefold reduction in peroxisome abundance was also observed for cells lacking either of two PTS1-targeted peroxisomal beta-oxidation enzymes, acyl-CoA oxidase and 2-enoyl-CoA hydratase/D-3-hydroxyacyl-CoA dehydrogenase. These results indicate that reduced peroxisome abundance in PBD cells may be caused by their inability to import these PTS1-containing enzymes. Furthermore, the fact that peroxisome abundance is influenced by peroxisomal 105-oxidation activities suggests that there may be metabolic control of peroxisome abundance.

scholarly journals Redox-regulated Cargo Binding and Release by the Peroxisomal Targeting Signal Receptor, Pex5

2013 ◽  
Vol 288 (38) ◽  
pp. 27220-27231 ◽  
Author(s):  
Changle Ma ◽  
Danielle Hagstrom ◽  
Soumi Guha Polley ◽  
Suresh Subramani
Keyword(s):  
Disulfide Bond ◽  
Protein Interactions ◽  
Matrix Protein ◽  
Protein Import ◽  
Redox Balance ◽  
Receptor Recycling ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Peroxisomal Targeting Signal ◽  
Cargo Binding

In its role as a mobile receptor for peroxisomal matrix cargo containing a peroxisomal targeting signal called PTS1, the protein Pex5 shuttles between the cytosol and the peroxisome lumen. Pex5 binds PTS1 proteins in the cytosol via its C-terminal tetratricopeptide domains and delivers them to the peroxisome lumen, where the receptor·cargo complex dissociates. The cargo-free receptor is exported to the cytosol for another round of import. How cargo release and receptor recycling are regulated is poorly understood. We found that Pex5 functions as a dimer/oligomer and that its protein interactions with itself (homo-oligomeric) and with Pex8 (hetero-oligomeric) control the binding and release of cargo proteins. These interactions are controlled by a redox-sensitive amino acid, cysteine 10 of Pex5, which is essential for the formation of disulfide bond-linked Pex5 forms, for high affinity cargo binding, and for receptor recycling. Disulfide bond-linked Pex5 showed the highest affinity for PTS1 cargo. Upon reduction of the disulfide bond by dithiothreitol, Pex5 transitioned to a noncovalent dimer, concomitant with the partial release of PTS1 cargo. Additionally, dissipation of the redox balance between the cytosol and the peroxisome lumen caused an import defect. A hetero-oligomeric interaction between the N-terminal domain (amino acids 1–110) of Pex5 and a conserved motif at the C terminus of Pex8 further facilitates cargo release, but only under reducing conditions. This interaction is also important for the release of PTS1 proteins. We suggest a redox-regulated model for Pex5 function during the peroxisomal matrix protein import cycle.

scholarly journals Peroxisomal Targeting Signal Receptor Pex5p Interacts with Cargoes and Import Machinery Components in a Spatiotemporally Differentiated Manner: Conserved Pex5p WXXXF/Y Motifs Are Critical for Matrix Protein Import

2002 ◽  
Vol 22 (6) ◽  
pp. 1639-1655 ◽  
Author(s):  
Hidenori Otera ◽  
Kiyoko Setoguchi ◽  
Maho Hamasaki ◽  
Toshitaka Kumashiro ◽  
Nobuhiro Shimizu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Matrix Protein ◽  
Protein Import ◽  
Tetratricopeptide Repeat ◽  
Amino Acid Residues ◽  
Peroxisomal Targeting ◽  
Signal Type ◽  
Targeting Signal ◽  
Peroxisomal Targeting Signal

ABSTRACT Two isoforms of the peroxisomal targeting signal type 1 (PTS1) receptor, termed Pex5pS and (37-amino-acid-longer) Pex5pL, are expressed in mammals. Pex5pL transports PTS1 proteins and Pex7p-PTS2 cargo complexes to the initial Pex5p-docking site, Pex14p, on peroxisome membranes, while Pex5pS translocates only PTS1 cargoes. Here we report functional Pex5p domains responsible for interaction with peroxins Pex7p, Pex13p, and Pex14p. An N-terminal half, such as Pex5pL(1-243), comprising amino acid residues 1 to 243, bound to Pex7p, Pex13p, and Pex14p and was sufficient for restoring the impaired PTS2 import of pex5 cell mutants, while the C-terminal tetratricopeptide repeat motifs were required for PTS1 binding. N-terminal Pex5p possessed multiple Pex14p-binding sites. Alanine-scanning analysis of the highly conserved seven (six in Pex5pS) pentapeptide WXXXF/Y motifs residing at the N-terminal region indicated that these motifs were essential for the interaction of Pex5p with Pex14p and Pex13p. Moreover, mutation of several WXXXF/Y motifs did not affect the PTS import-restoring activity of Pex5p, implying that the binding of Pex14p to all of the WXXXF/Y sites was not a prerequisite for the translocation of Pex5p-cargo complexes. Pex5p bound to Pex13p at the N-terminal part, not to the C-terminal SH3 region, via WXXXF/Y motifs 2 to 4. PTS1 and PTS2 import required the interaction of Pex5p with Pex14p but not with Pex13p, while Pex5p binding to Pex13p was essential for import of catalase with PTS1-like signal KANL. Pex5p recruited PTS1 proteins to Pex14p but not to Pex13p. Pex14p and Pex13p formed a complex with PTS1-loaded Pex5p but dissociated in the presence of cargo-unloaded Pex5p, implying that PTS cargoes are released from Pex5p at a step downstream of Pex14p and upstream of Pex13p. Thus, Pex14p and Pex13p very likely form mutually and temporally distinct subcomplexes involved in peroxisomal matrix protein import.

scholarly journals Involvement of Pex13p in Pex14p Localization and Peroxisomal Targeting Signal 2–dependent Protein Import into Peroxisomes

1999 ◽  
Vol 144 (6) ◽  
pp. 1151-1162 ◽  
Author(s):  
Wolfgang Girzalsky ◽  
Peter Rehling ◽  
Katharina Stein ◽  
Julia Kipper ◽  
Lars Blank ◽  
...  
Keyword(s):  
Binding Sites ◽  
Protein Import ◽  
Sh3 Domain ◽  
Loss Of Function ◽  
Peroxisomal Membrane ◽  
Peroxisomal Targeting ◽  
Dependent Protein ◽  
Targeting Signal ◽  
Docking Protein ◽  
Peroxisomal Targeting Signal

Pex13p is the putative docking protein for peroxisomal targeting signal 1 (PTS1)-dependent protein import into peroxisomes. Pex14p interacts with both the PTS1- and PTS2-receptor and may represent the point of convergence of the PTS1- and PTS2-dependent protein import pathways. We report the involvement of Pex13p in peroxisomal import of PTS2-containing proteins. Like Pex14p, Pex13p not only interacts with the PTS1-receptor Pex5p, but also with the PTS2-receptor Pex7p; however, this association may be direct or indirect. In support of distinct peroxisomal binding sites for Pex7p, the Pex7p/Pex13p and Pex7p/ Pex14p complexes can form independently. Genetic evidence for the interaction of Pex7p and Pex13p is provided by the observation that overexpression of Pex13p suppresses a loss of function mutant of Pex7p. Accordingly, we conclude that Pex7p and Pex13p functionally interact during PTS2-dependent protein import into peroxisomes. NH2-terminal regions of Pex13p are required for its interaction with the PTS2-receptor while the COOH-terminal SH3 domain alone is sufficient to mediate its interaction with the PTS1-receptor. Reinvestigation of the topology revealed both termini of Pex13p to be oriented towards the cytosol. We also found Pex13p to be required for peroxisomal association of Pex14p, yet the SH3 domain of Pex13p may not provide the only binding site for Pex14p at the peroxisomal membrane.

scholarly journals A PEX7-Centered Perspective on the Peroxisomal Targeting Signal Type 2-Mediated Protein Import Pathway

2014 ◽  
Vol 34 (15) ◽  
pp. 2917-2928 ◽  
Author(s):  
T. A. Rodrigues ◽  
I. S. Alencastre ◽  
T. Francisco ◽  
P. Brites ◽  
M. Fransen ◽  
...  
Keyword(s):  
Protein Import ◽  
Peroxisomal Targeting ◽  
Signal Type ◽  
Targeting Signal ◽  
Peroxisomal Targeting Signal

scholarly journals A conserved tripeptide sorts proteins to peroxisomes.

1989 ◽  
Vol 108 (5) ◽  
pp. 1657-1664 ◽  
Author(s):  
S J Gould ◽  
G A Keller ◽  
N Hosken ◽  
J Wilkinson ◽  
S Subramani
Keyword(s):  
Protein Import ◽  
Firefly Luciferase ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Luciferase Gene ◽  
Luciferase Protein ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Peroxisomal Targeting Signal ◽  
Made In

The firefly luciferase protein contains a peroxisomal targeting signal at its extreme COOH terminus (Gould et al., 1987). Site-directed mutagenesis of the luciferase gene reveals that this peroxisomal targeting signal consists of the COOH-terminal three amino acids of the protein, serine-lysine-leucine. When this tripeptide is appended to the COOH terminus of a cytosolic protein (chloramphenicol acetyltransferase), it is sufficient to direct the fusion protein into peroxisomes. Additional mutagenesis experiments reveal that only a limited number of conservative changes can be made in this tripeptide targeting signal without abolishing its activity. These results indicate that peroxisomal protein import, unlike other types of transmembrane translocation, is dependent upon a conserved amino acid sequence.

Components Involved in Peroxisome Import, Biogenesis, Proliferation, Turnover, and Movement

1998 ◽  
Vol 78 (1) ◽  
pp. 171-188 ◽  
Author(s):  
SURESH SUBRAMANI
Keyword(s):  
Protein Import ◽  
Protein Translocation ◽  
Peroxisomal Disorders ◽  
Peroxisomal Membrane ◽  
Peroxisomal Protein ◽  
Peroxisomal Targeting ◽  
Docking Proteins ◽  
Targeting Signal ◽  
Peroxisomal Targeting Signal

Subramani, Suresh. Components Involved in Peroxisome Import, Biogenesis, Proliferation, Turnover, and Movement. Physiol. Rev. 78: 171–188, 1998. — In the decade that has elapsed since the discovery of the first peroxisomal targeting signal (PTS), considerable information has been obtained regarding the mechanism of protein import into peroxisomes. The PTSs responsible for the import of matrix and membrane proteins to peroxisomes, the receptors for several of these PTSs, and docking proteins for the PTS1 and PTS2 receptors are known. Many peroxins involved in peroxisomal protein import and biogenesis have been characterized genetically and biochemically. These studies have revealed important new insights regarding the mechanism of protein translocation across the peroxisomal membrane, the conservation of PEX genes through evolution, the role of peroxins in fatal human peroxisomal disorders, and the biogenesis of the organelle. It is clear that peroxisomal protein import and biogenesis have many features unique to this organelle alone. More recent studies on peroxisome degradation, division, and movement highlight newer aspects of the biology of this organelle that promise to be just as exciting and interesting as import and biogenesis.

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