scholarly journals The import receptor for the peroxisomal targeting signal 2 (PTS2) in Saccharomyces cerevisiae is encoded by the PAS7 gene.

1996 ◽  
Vol 15 (12) ◽  
pp. 2901-2913 ◽  
Author(s):  
P. Rehling ◽  
M. Marzioch ◽  
F. Niesen ◽  
E. Wittke ◽  
M. Veenhuis ◽  
...  
2004 ◽  
Vol 78 (9) ◽  
pp. 4744-4752 ◽  
Author(s):  
Beatriz Navarro ◽  
Luisa Rubino ◽  
Marcello Russo

ABSTRACT Open reading frame 1 in the viral genome of Cymbidium ringspot virus encodes a 33-kDa protein (p33), which was previously shown to localize to the peroxisomal membrane in infected and transgenic plant cells. To determine the sequence requirements for the organelle targeting and membrane insertion, the protein was expressed in the yeast Saccharomyces cerevisiae in native form (33K) or fused to the green fluorescent protein (33KGFP). Cell organelles were identified by immunolabeling of marker proteins. In addition, peroxisomes were identified by simultaneous expression of the red fluorescent protein DsRed containing a peroxisomal targeting signal and mitochondria by using the dye MitoTracker. Fluorescence microscopy showed the 33KGFP fusion protein concentrated in a few large bodies colocalizing with peroxisomes. These bodies were shown by electron microscopy to be composed by aggregates of peroxisomes, a few mitochondria and endoplasmic reticulum (ER) strands. In immunoelectron microscopy, antibodies to p33 labeled the peroxisomal clumps. Biochemical analysis suggested that p33 is anchored to the peroxisomal membrane through a segment of ca. 7 kDa, which corresponds to the sequence comprising two hydrophobic transmembrane domains and a hydrophilic interconnecting loop. Analysis of deletion mutants confirmed these domains as essential components of the p33 peroxisomal targeting signal, together with a cluster of three basic amino acids (KRR). In yeast mutants lacking peroxisomes p33 was detected in the ER. The possible involvement of the ER as an intermediate step for the integration of p33 into the peroxisomal membrane is discussed.


2001 ◽  
Vol 276 (18) ◽  
pp. 15034-15041 ◽  
Author(s):  
André T. J. Klein ◽  
Phil Barnett ◽  
Gina Bottger ◽  
Daphne Konings ◽  
Henk F. Tabak ◽  
...  

1993 ◽  
Vol 120 (3) ◽  
pp. 665-673 ◽  
Author(s):  
F Kragler ◽  
A Langeder ◽  
J Raupachova ◽  
M Binder ◽  
A Hartig

In contrast to many other peroxisomal proteins catalase A contains at least two peroxisomal targeting signals each sufficient to direct reporter proteins to peroxisomes. One of them resides at the extreme carboxy terminus constituting a new variant of this signal, -SSNSKF, not active in monkey kidney cells (Gould, S. J., G. A. Keller, N. Hosken, J. Wilkinson, and S. Subramani 1989. J. Cell Biol. 108:1657-1664). However, this signal is completely dispensable for import of catalase A itself. In its amino-terminal third this protein contains another peroxisomal targeting signal sufficient to direct reporter proteins into microbodies. This internal signal depends on the context. The nature of this targeting signal might be a short defined sequence or a structural feature recognized by import factors. In addition, we have demonstrated that the carboxy-terminal seven amino acids of citrate synthase of Saccharomyces cerevisiae encoded by CIT2 and containing the canonical -SKL represents a targeting signal sufficient to direct reporter proteins to peroxisomes.


2011 ◽  
Vol 10 (6) ◽  
pp. 770-775 ◽  
Author(s):  
Sven Thoms ◽  
Mykhaylo O. Debelyy ◽  
Melanie Connerth ◽  
Günther Daum ◽  
Ralf Erdmann

ABSTRACT Here, we report the identification of a novel hydrolase in Saccharomyces cerevisiae . Ldh1p (systematic name, Ybr204cp) comprises the typical GXSXG-type lipase motif of members of the α/β-hydrolase family and shares some features with the peroxisomal lipase Lpx1p. Both proteins carry a putative peroxisomal targeting signal type1 (PTS1) and can be aligned with two regions of homology. While Lpx1p is known as a peroxisomal enzyme, subcellular localization studies revealed that Ldh1p is predominantly localized to lipid droplets, the storage compartment of nonpolar lipids. Ldh1p is not required for the function and biogenesis of peroxisomes, and targeting of Ldh1p to lipid droplets occurs independently of the PTS1 receptor Pex5p.


1992 ◽  
Vol 12 (12) ◽  
pp. 5593-5599
Author(s):  
K K Singh ◽  
G M Small ◽  
A S Lewin

The tripeptide serine-lysine-leucine (SKL) occurs at the carboxyl terminus of many peroxisomal proteins and serves as a peroxisomal targeting signal. Saccharomyces cerevisiae has two isozymes of citrate synthase. The peroxisomal form, encoded by CIT2, terminates in SKL, while the mitochondrial form, encoded by CIT1, begins with an amino-terminal mitochondrial signal sequence and ends in SKN. We analyzed the importance of SKL as a topogenic signal for citrate synthase, using oleate to induce peroxisomes and density gradients to fractionate organelles. Our experiments revealed that SKL was necessary for directing citrate synthase to peroxisomes. C-terminal SKL was also sufficient to target a leaderless version of mitochondrial citrate synthase to peroxisomes. Deleting this tripeptide from the CIT2 protein caused peroxisomal citrate synthase to be missorted to mitochondria. These experiments suggest that the CIT2 protein contains a cryptic mitochondrial targeting signal.


1992 ◽  
Vol 12 (12) ◽  
pp. 5593-5599 ◽  
Author(s):  
K K Singh ◽  
G M Small ◽  
A S Lewin

The tripeptide serine-lysine-leucine (SKL) occurs at the carboxyl terminus of many peroxisomal proteins and serves as a peroxisomal targeting signal. Saccharomyces cerevisiae has two isozymes of citrate synthase. The peroxisomal form, encoded by CIT2, terminates in SKL, while the mitochondrial form, encoded by CIT1, begins with an amino-terminal mitochondrial signal sequence and ends in SKN. We analyzed the importance of SKL as a topogenic signal for citrate synthase, using oleate to induce peroxisomes and density gradients to fractionate organelles. Our experiments revealed that SKL was necessary for directing citrate synthase to peroxisomes. C-terminal SKL was also sufficient to target a leaderless version of mitochondrial citrate synthase to peroxisomes. Deleting this tripeptide from the CIT2 protein caused peroxisomal citrate synthase to be missorted to mitochondria. These experiments suggest that the CIT2 protein contains a cryptic mitochondrial targeting signal.


Genomics ◽  
1995 ◽  
Vol 30 (2) ◽  
pp. 366-368 ◽  
Author(s):  
Peter Marynen ◽  
Marc Fransen ◽  
Peter Raeymaekers ◽  
Guy P. Mannaerts ◽  
Paul P. Van Veldhoven

Author(s):  
G-A. Keller ◽  
S. J. Gould ◽  
S. Subramani ◽  
S. Krisans

Subcellular compartments within eukaryotic cells must each be supplied with unique sets of proteins that must be directed to, and translocated across one or more membranes of the target organelles. This transport is mediated by cis- acting targeting signals present within the imported proteins. The following is a chronological account of a series of experiments designed and carried out in an effort to understand how proteins are targeted to the peroxisomal compartment.-We demonstrated by immunocryoelectron microscopy that the enzyme luciferase is a peroxisomal enzyme in the firefly lantern. -We expressed the cDNA encoding firefly luciferase in mammalian cells and demonstrated by immunofluorescence that the enzyme was transported into the peroxisomes of the transfected cells. -Using deletions, linker insertions, and gene fusion to identify regions of luciferase involved in its transport to the peroxisomes, we demonstrated that luciferase contains a peroxisomal targeting signal (PTS) within its COOH-terminal twelve amino acid.


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