Targeting efficiencies of various permutations of the consensus C‐terminal tripeptide peroxisomal targeting signal

Swinkels, B.W.; Gould, Stephen J.; Subramani, Suresh

doi:10.1016/0014-5793(92)80880-p

Cited by 125 publications

(101 citation statements)

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“…Construction of the expression plasmids, pEXcAtsEH1122 (a) and pEXcAtsEH589 (b), and their products. (Arand et aL, 1991), and the C-terminal SKM sequence was also postulated to serve as a weak localization signal to peroxisomes in monkey (Swinkels et a/.,1992). The three deduced C-terminal residues of AtsEH are SKF, which resembles those of human and mouse sEHs, SKM and SKI, respectively.…”

Section: Discussionmentioning

confidence: 99%

Characterization of an Arabidopsis cDNA for a soluble epoxide hydrolase gene that is inducible by auxin and water stress

et al. 1994

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SummaryA cDNA (1122 bp) was isolated from a cDNA library prepared from Arabidopais thaliana L. that had been subjected to drought stress for I h. The sequencing of a genomic clone corresponding to the cDNA and Sl mepplng analysis revealed that the cDNA lacked the first 6 bp from its translational start (ATG). The resulting open reading frame encodes a polypaptlde of 321 amino acids, and the calculated molecular weight of this polypeptide is 36 423 De. The deduced amino acid sequence shows a high degree of similarity to C terminal halves of those of soluble epoxide hydrolases (sEHs) of human, mouse and rat, 35.5%, 34.1% and 33.1%, respectively. The cDNA was expressed In Escherichla coil cells, and the expressed protein migrates at 40 kDa when analyzed by SDS-PAGE. The recombinant protein at 40 kDa Is much smaller than the mammalian sEH (58 kDa) but has characteristics of activity and inhibition slmller to the mammalian sEHs when assayed with the substrate trans-stilbene oxide and the inhibitors 4-fluorochalcone oxide (4FCO), (2R,3R)-3-(4-nitrophenyl) glycidol (RRNPG), and (2S,3S)-3-(4-nitrophenyl)glycidol (SSNPG), which indicates that the cDNA did encode a soluble epoxide hydrolese of A. thallana (AtsEH). Drought stress, but not heat or cold stress, slightly Increased the accu-

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Section: Discussionmentioning

confidence: 99%

Characterization of an Arabidopsis cDNA for a soluble epoxide hydrolase gene that is inducible by auxin and water stress

et al. 1994

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“…In this context, it is interesting to note that of the three non-synonymous polymorphisms found in human AGT (i.e. Pro 11 3 Leu, Val 326 3 Ile, and Ile 340 3 Met) (42), two are located in the 22-residue PTS1A. Ile 340 3 Met segregates with the minor AGXT allele, which also contains Pro 11 3 Leu.…”

Section: Cell Context Dependence Of the Interaction Between Humanmentioning

confidence: 99%

“…Pro 11 3 Leu, Val 326 3 Ile, and Ile 340 3 Met) (42), two are located in the 22-residue PTS1A. Ile 340 3 Met segregates with the minor AGXT allele, which also contains Pro 11 3 Leu. Val 326 3 Ile segregates with a variant called the minor (African) AGXT allele (43).…”

Section: Cell Context Dependence Of the Interaction Between Humanmentioning

confidence: 99%

“…However, several features of the peroxisomal targeting of AGT are unusual when compared with the targeting of other peroxisomal proteins. The C-terminal tripeptide of human AGT is KKL (9), which has a two-out-of-three match with the prototypical consensus PTS1 of (S/A/C)(K/R/H)(L/M) (10,11). KKL is necessary for peroxisomal targeting of human AGT but insufficient to direct the peroxisomal targeting of reporter proteins, such as bacterial chloramphenicol acetyltransferase or firefly luciferase (7,12).…”

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confidence: 99%

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Peroxisomal Import of Human Alanine:glyoxylate Aminotransferase Requires Ancillary Targeting Information Remote from Its C Terminus

Huber

Birdsey

Lumb

et al. 2005

Journal of Biological Chemistry

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Although human alanine:glyoxylate aminotransferase (AGT) is imported into peroxisomes by a Pex5p-dependent pathway, the properties of its C-terminal tripeptide (KKL) are unlike those of any other type 1 peroxisomal targeting sequence (PTS1). We have previously suggested that AGT might possess ancillary targeting information that enables its unusual PTS1 to work. In this study, we have attempted to locate this information and to determine whether or not it is a characteristic of all vertebrate AGTs. Using the two-hybrid system, we show that human AGT interacts with human Pex5p in mammalian cells, but not yeast cells. Using (immuno)fluorescence microscopic analysis of the distribution of various constructs expressed in COS cells, we show the following. 1) The putative ancillary peroxisomal targeting information (PTS1A) in human AGT is located entirely within the smaller C-terminal structural domain of 110 amino acids, with the sequence between Val-324 and Ile-345 being the most likely candidate region. 2) The PTS1A is present in all mammalian AGTs studied (human, rat, guinea pig, rabbit, and cat), but not amphibian AGT (Xenopus). 3) The PTS1A is necessary for peroxisomal import of human, rabbit, and cat AGTs, but not rat and guinea pig AGTs. We speculate that the internal PTS1A of human AGT works in concert with the C-terminal PTS1 by interacting with Pex5p indirectly with the aid of a yet-to-be-identified mammal-specific adaptor molecule. This interaction might reshape the tetratricopeptide repeat domain allosterically, enabling it to accept KKL as a functional PTS1.Alanine:glyoxylate aminotransferase (AGT, 1 EC 2.6.1.44) catalyzes the transamination of the intermediary metabolite glyoxylate to glycine. A deficiency of AGT, as occurs in the hereditary disease primary hyperoxaluria type 1, allows glyoxylate to be oxidized to oxalate instead. The resulting increased synthesis and excretion of oxalate leads to the deposition of insoluble calcium oxalate in the kidney and urinary tract and, ultimately, renal failure (1). AGT is normally peroxisomal in human liver, but in a subset of primary hyperoxaluria type 1 patients it is mistargeted to mitochondria (2). Although the molecular basis of the peroxisome-to-mitochondrion mistargeting of AGT in primary hyperoxaluria type 1 has been subjected to extensive investigation (3-6), its normal targeting to peroxisomes has received much less attention (7,8).Peroxisomal import of human AGT is dependent on the presence of the type 1 peroxisomal targeting sequence (PTS1) receptor Pex5p, but not the PTS2 receptor Pex7p (7). However, several features of the peroxisomal targeting of AGT are unusual when compared with the targeting of other peroxisomal proteins. The C-terminal tripeptide of human AGT is KKL (9), which has a two-out-of-three match with the prototypical consensus PTS1 of (S/A/C)(K/R/H)(L/M) (10, 11). KKL is necessary for peroxisomal targeting of human AGT but insufficient to direct the peroxisomal targeting of reporter proteins, such as bacterial chloramphenicol acetyl...

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“…In the cytosol, Pex5p binds to proteins carrying a type I peroxisomal targeting signal (PTS1), which is a carboxyl-terminal tripeptide with the consensus sequence S/A/C-K/R/H-L/M (Gould et al, 1989;Swinkels et al, 1992). However, depending on the species and protein under study the carboxyl-terminal tripeptide may deviate from the consensus, and residues just upstream of it also can contribute to Pex5p binding and peroxisomal targeting (Lametschwandtner et al, 1998;Purdue & Lazarow, 1996).…”

Section: Introductionmentioning

confidence: 99%

The activity of the glyoxylate cycle in peroxisomes of Candida albicans depends on a functional β-oxidation pathway: evidence for reduced metabolite transport across the peroxisomal membrane

et al. 2008

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The glyoxylate cycle, a metabolic pathway required for generating C 4 units from C 2 compounds, is an important factor in virulence, in both animal and plant pathogens. Here, we report the localization of the key enzymes of this cycle, isocitrate lyase (Icl1; EC 4.1.3.1) and malate synthase (Mls1; EC 2.3.3.9), in the human fungal pathogen Candida albicans. Immunocytochemistry in combination with subcellular fractionation showed that both Icl1 and Mls1 are localized to peroxisomes, independent of the carbon source used. Although Icl1 and Mls1 lack a consensus type I peroxisomal targeting signal (PTS1), their import into peroxisomes was dependent on the PTS1 receptor Pex5p, suggesting the presence of non-canonical targeting signals in both proteins. Peroxisomal compartmentalization of the glyoxylate cycle is not essential for proper functioning of this metabolic pathway because a pex5D/D strain, in which Icl1 and Mls1 were localized to the cytosol, grew equally as well as the wild-type strain on acetate and ethanol. Previously, we reported that a fox2D/D strain that is completely deficient in fatty acid boxidation, but has no peroxisomal protein import defect, displayed strongly reduced growth on non-fermentable carbon sources such as acetate and ethanol. Here, we show that growth of the fox2D/D strain on these carbon compounds can be restored when Icl1 and Mls1 are relocated to the cytosol by deleting the PEX5 gene. We hypothesize that the fox2D/D strain is disturbed in the transport of glyoxylate cycle products and/or acetyl-CoA across the peroxisomal membrane and discuss the possible relationship between such a transport defect and the presence of giant peroxisomes in the fox2D/D mutant.

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Targeting efficiencies of various permutations of the consensus C‐terminal tripeptide peroxisomal targeting signal

Cited by 125 publications

References 10 publications

Characterization of an Arabidopsis cDNA for a soluble epoxide hydrolase gene that is inducible by auxin and water stress

Characterization of an Arabidopsis cDNA for a soluble epoxide hydrolase gene that is inducible by auxin and water stress

Peroxisomal Import of Human Alanine:glyoxylate Aminotransferase Requires Ancillary Targeting Information Remote from Its C Terminus

The activity of the glyoxylate cycle in peroxisomes of Candida albicans depends on a functional β-oxidation pathway: evidence for reduced metabolite transport across the peroxisomal membrane

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