Human peroxisomal <scp>l</scp>-alanine: glyoxylate aminotransferase. Evolutionary loss of a mitochondrial targeting signal by point mutation of the initiation codon

Takada, Yoshikazu; Kaneko, Naomi; Esumi, Hiroyasu; Purdue, P. Edward; Danpure, Christopher J.

doi:10.1042/bj2680517

Cited by 100 publications

(58 citation statements)

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“…The amino acid sequence deduced from the upstream open reading frame was compared against the protein data bank, and similarity was found with human peroxisomal alanine:glyoxylate aminotransferase (42,51), mitochondrial serine:pyruvate aminotransferase from rat liver (38), and the small subunit of soluble hydrogenase from Anabaena cylindrica (14) and Synechococcus sp. strain PCC 6716 (56), all apparently belonging to the same family of enzymes.…”

Section: Methodsmentioning

confidence: 99%

Genetics of the serine cycle in Methylobacterium extorquens AM1: identification of sgaA and mtdA and sequences of sgaA, hprA, and mtdA

Chistoserdova

Lidstrom

1994

J Bacteriol

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Section: Methodsmentioning

confidence: 99%

Genetics of the serine cycle in Methylobacterium extorquens AM1: identification of sgaA and mtdA and sequences of sgaA, hprA, and mtdA

Chistoserdova

Lidstrom

1994

J Bacteriol

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“…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).…”

mentioning

confidence: 99%

“…For example, it is KKL in human (9) and marmoset (20), HRL in guinea pig (21), SQL in rabbit (20), NKL in rat (22), mouse (23), and cat (24), HKL in dog (EMBL accession number AAEX01037931/2, Canis familiaris chromosome 25 contig 37930/1), and SKL in cow (EMBL accession number AV605720, Bos taurus cDNA). This evolutionary variability differs from archetypal PTS1 proteins, such as urate oxidase, the C terminus of which (i.e.…”

mentioning

confidence: 99%

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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“…Human AGXT cDNA was cloned (1,2), and its genomic structure is known (3). A number of mutations at the AGXT gene have been found in PH1 patients (www.uwcm.ac.uk͞uwcm͞mg͞ hgmd0.html).…”

mentioning

confidence: 99%

Primary hyperoxaluria type 1 in the Canary Islands: A conformational disease due to I244T mutation in the P11L-containing alanine:glyoxylate aminotransferase

Santana

Salido

Torres

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

116

105

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Primary hyperoxaluria type 1 (PH1) is an inborn error of metabolism resulting from a deficiency of alanine:glyoxylate aminotransferase (AGXT; EC 2.6.1.44). Most of the PH1 alleles detected in the Canary Islands carry the Ile-244 3 Thr (I244T) mutation in the AGXT gene, with 14 of 16 patients homozygous for this mutation. Four polymorphisms within AGXT and regional microsatellites also were shared in their haplotypes (AGXT*LTM), consistent with a founder effect. The consequences of these amino acid changes were investigated. Although I244T alone did not affect AGXT activity or subcellular localization, when present in the same protein molecule as Leu-11 3 Pro (L11P), it resulted in loss of enzymatic activity in soluble cell extracts. Like its normal counterpart, the AGXT*LTM protein was present in the peroxisomes but it was insoluble in detergent-free buffers. The polymorphism L11P behaved as an intragenic modifier of the I244T mutation, with the resulting protein undergoing stable interaction with molecular chaperones and aggregation. This aggregation was temperature-sensitive. AGXT*LTM expressed in Escherichia coli, as a GST-fusion protein, and in insect cells could be purified and retained enzymatic activity. Among various chemical chaperones tested in cell culture, betaine substantially improved the solubility of the mutant protein and the enzymatic activity in cell lysates. In summary, I244T, the second most common mutation responsible for PH1, is a protein conformational disease that may benefit from new therapies with pharmacological chaperones or small molecules to minimize protein aggregation.

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Human peroxisomal l-alanine: glyoxylate aminotransferase. Evolutionary loss of a mitochondrial targeting signal by point mutation of the initiation codon

Cited by 100 publications

References 28 publications

Genetics of the serine cycle in Methylobacterium extorquens AM1: identification of sgaA and mtdA and sequences of sgaA, hprA, and mtdA

Genetics of the serine cycle in Methylobacterium extorquens AM1: identification of sgaA and mtdA and sequences of sgaA, hprA, and mtdA

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

Primary hyperoxaluria type 1 in the Canary Islands: A conformational disease due to I244T mutation in the P11L-containing alanine:glyoxylate aminotransferase

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