Urate oxidase is imported into peroxisomes recognizing the C‐terminal SKL motif of proteins

Miura, Satoshi; Oda, Toshiaki; Funai, Tsuneyoshi; Ito, Masaki; Okada, Yoshiie; Ichiyama, Arata

doi:10.1111/j.1432-1033.1994.tb18975.x

Cited by 16 publications

(14 citation statements)

References 46 publications

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“…Amidation of the peptide corresponding to the wild-type AOX sequence abolished its ability to act as a competitor, demonstrating that a free c~-carboxyl group is important in recognition of the targeting sequence. Similar results were also reported for urate oxidase from rat liver, which ends with the tripeptide sequence serine-arginine-leucine [34]. Mutation of this sequence to serine-lysine-leucine supported import of the protein, but serine-glutamic acid-leucine did not.…”

Section: What In Vitro Systems Have Taught Us Targetingsupporting

confidence: 86%

“…The major limitation to date has been the relatively low efficiencies of protein import achieved. While efficiencies of up to 30% have been reported [19,40] 5-10% or even less is more common [20,24,34,36]. This may indicate that the existing systems are not optimal, but is almost certainly in part due to the fragility of the peroxisomes.…”

Section: Conclusion and Future Prospectsmentioning

confidence: 82%

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In vitro systems in the study of peroxisomal protein import

Baker

1996

Experientia

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Our level of understanding of peroxisome biogenesis in comparison with other cellular organelles is rudimentary, yet the fragments of information available indicate that the targeting and import of peroxisomal proteins occur by fundamentally different mechanisms. Genetic studies have identified a number of genes required for peroxisome assembly, but in most cases the functions of the gene products remain unknown. In vitro protein translocation systems have played a prominent role in unravelling the biochemistry of protein translocation into other organelles. This review considers some of the requirements for establishing a bona fide peroxisomal import assay and discusses the findings which have emerged as a result of using such experimental systems.

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Section: What In Vitro Systems Have Taught Us Targetingsupporting

confidence: 86%

Section: Conclusion and Future Prospectsmentioning

confidence: 82%

In vitro systems in the study of peroxisomal protein import

Baker

1996

Experientia

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“…The uricase II-coding regions share a high percentage of identity at the nucleotide (90% with soybean; 94% with cowpea) and amino acid levels (91% with soybean; 95% with cowpea). The bean uricase II cDNA encodes a protein of 308 amino acids that contains the four conserved motifs present in all urate oxidases described previously: the V-L-K-T-T-Q-S motif (Bairoch, 1991) and the S-P-S-V-Q-K/ H/N-T-L-Y motif, each of unknown function; the H-X-H-X-F motif that joined to a third His (residue 266 in bean uricase) forms the protein copper-binding site proposed by Wu et al (1989); and the tripeptide S-Basic-L (S-K-L for bean, soybean, and cowpea uricase II), the signal for peroxisome entry localized at the carboxyl terminus of the protein (Motojima and Goto, 1989;Wallrath et al, 1990;van den Bosch, 1992;Miura et al, 1994;Fig. IB).…”

Section: Isolation and Characterization Of A Uricase II Cdna Clonementioning

confidence: 99%

Characterization of the Common Bean Uricase II and Its Expression in Organs Other than Nodules

Capote

Sánchez

1997

Plant Physiology

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Uricase II is a purine metabolic enzyme highly induced in root nodules during the symbiosis established between legumes and bacteria of the genera Rhizobium and Bradyrhizobium. Here we describe the characterization of bean (Phaseolus vulgaris) nodule uricase II cDNA and show that uricase I I is encoded by a single gene in the bean genome. This gene is also expressed in cotyledons, roots, and hypocotyls during bean seedling establishment, and an antiuricase antibody recognizes the protein in different seedling organs. Uricase II has also been found in leucaena leucocephala seedlings, suggesting that it participates during seedling establishment in legumes that do not transport ureides. A 50-kD polypeptide that is detected by the anti-uricase antibody is found in cotyledons during seedling development. This higher-molecular-mass form is also detected in developing roots and hypocotyls but not in nodules. In situ hybridization experiments in root seedlings showed uricase II transcripts in the metaxylem parenchyma cells and phloem fibers of the vascular system.

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“…After chase periods of 2.5-10 min, the amount of 35 S-PMP70 decreased in the postperoxisomal fraction and increased in the particulate fraction (lanes 3-10). After a 15-min chase, 35 S-PMP70 was detected only in the particulate fractions (lanes [11][12][13][14][15][16][17][18]. The molecular size of 35 S-PMP70 did not change during a chase period of 1 h. The localization of 35 S-PMP70 was further analyzed by sucrose gradient centifugation (Fig.…”

Section: Intracellular Transport and Sorting Of Pmp70 In H-4-ii-e Celmentioning

confidence: 99%

Insertion of the 70-kDa Peroxisomal Membrane Protein into Peroxisomal Membranes in Vivo and in Vitro

Imanaka

Shiina

Takano

et al. 1996

Journal of Biological Chemistry

117

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S-PMP70s, with a molecular mass greater than 50 kDa, bound to and inserted into peroxisomal membranes, whereas truncated 35 S-PMP70s smaller than 45 kDa did not. These results suggest that PMP70 is post-translationally transported to peroxisomes without processing and inserted into peroxisomal membranes by a specific mechanism in which a proteinaceous receptor and a certain internal sequence of PMP70 are involved.Peroxisomes are organelles bounded by a single membrane which are present in almost all eukaryotic cells. The peroxisomes are involved in a variety of metabolic processes including peroxide-based respiration, oxidative degradation of purines and fatty acids, and synthesis of plasmalogen and bile acids (1, 2). It has recently been suggested that peroxisomes are formed by post-translational import of newly synthesized proteins into pre-existing peroxisomes, which then divide (3-5). In rat liver, it is known that matrix proteins in peroxisomes are all synthesized on free polysomes in the cytosol. Post-translational import of these proteins into peroxisomes has been shown by in vivo pulse-chase (6, 7) and also by in vitro import experiments (8 -12). We developed an in vitro system based on the import of radiolabeled acyl-CoA oxidase (AOx) 1 into purified rat liver peroxisomes and showed that ATP hydrolysis was required for the translocation of AOx through peroxisomal membranes (9). At least two types of peroxisomal targeting sequences (PTSs) have been found. PTS1 consists of the sequence Ser-Lys-Leu (or closely related) at the carboxyl terminus (10, 13) and PTS2, which in 3-ketoacyl-CoA thiolase is found in the 11 amino acids of the amino-terminal leader sequence (14,15).The membranes of rat liver peroxisomes contain several integral membrane proteins not found in other organelles. Polypeptides of 69/70 and 22 kDa have been identified as major components and polypeptides of 57, 53, 35/36, and 26/27 kDa have been identified as minor components of peroxisomal membranes (16 -19). The 70-kDa peroxisomal membrane protein (PMP70) is markedly induced by administration of hypolipidemic agents and parallels peroxisome proliferation (17, 18). We cloned and sequenced PMP70 and found that PMP70 belonged to a superfamily called an ATP-binding cassette protein, conferring multidrug resistance to tumor cells (20). Recently PMP70 was suggested to be essential for peroxisome formation (21). PMP22 was also cloned and sequenced and it was suggested that the topology of PMP22 was similar to those of Mpv 17 and certain transmitter gated ion channels, although the function of PMP22 has not yet been described (22). Recently peroxisome assembly factor 1, a peroxisomal integral membrane protein with molecular mass of 35 kDa was also cloned and sequenced (23).A number of studies have been carried out to further investigate the biogenesis of peroxisomal membrane proteins (PMPs). We, and other laboratories, have shown that PMP70, -26, and -22 were synthesized on free polysomes (24 -26), suggesting that the PMPs are likely to be insert...

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Urate oxidase is imported into peroxisomes recognizing the C‐terminal SKL motif of proteins

Cited by 16 publications

References 46 publications

In vitro systems in the study of peroxisomal protein import

In vitro systems in the study of peroxisomal protein import

Characterization of the Common Bean Uricase II and Its Expression in Organs Other than Nodules

Insertion of the 70-kDa Peroxisomal Membrane Protein into Peroxisomal Membranes in Vivo and in Vitro

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