| Structural highlights
Disease
[SPYA_HUMAN] Defects in AGXT are the cause of hyperoxaluria primary type 1 (HP1) [MIM:259900]; also known as primary hyperoxaluria type I (PH1) and oxalosis I. HP1 is a rare autosomal recessive inborn error of glyoxylate metabolism characterized by increased excretion of oxalate and glycolate, and the progressive accumulation of insoluble calcium oxalate in the kidney and urinary tract.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18]
Publication Abstract from PubMed
Primary hyperoxaluria type I (PH1) is a conformational disease which result in the loss of alanine:glyoxylate aminotransferase (AGT) function. The study of AGT has important implications for protein folding and trafficking because PH1 mutants may cause protein aggregation and mitochondrial mistargeting. We herein describe a multidisciplinary study aimed to understand the molecular basis of protein aggregation and mistargeting in PH1 by studying twelve AGT variants. Expression studies in cell cultures reveal strong protein folding defects in PH1 causing mutants leading to enhanced aggregation, and in two cases, mitochondrial mistargeting. Immunoprecipitation studies in a cell-free system reveal that most mutants enhance the interactions with Hsc70 chaperones along their folding process, while in vitro binding experiments show no changes in the interaction of folded AGT dimers with the peroxisomal receptor Pex5p. Thermal denaturation studies by calorimetry support that PH1 causing mutants often kinetically destabilize the folded apo-protein through significant changes in the denaturation free energy barrier, whereas coenzyme binding overcomes this destabilization. Modeling of the mutations on a 1.9 A crystal structure suggests that PH1 causing mutants perturb locally the native structure. Our work support that a misbalance between denaturation energetics and interactions with chaperones underlie aggregation and mistargeting in PH1, suggesting that native state stabilizers and protein homeostasis modulators are potential drugs to restore the complex and delicate balance of AGT protein homeostasis in PH1.
The role of protein denaturation energetics and molecular chaperones in the aggregation and mistargeting of mutants causing primary hyperoxaluria type I.,Mesa-Torres N, Fabelo-Rosa I, Riverol D, Yunta C, Albert A, Salido E, Pey AL PLoS One. 2013 Aug 27;8(8):e71963. doi: 10.1371/journal.pone.0071963. PMID:24205397[19]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Purdue PE, Takada Y, Danpure CJ. Identification of mutations associated with peroxisome-to-mitochondrion mistargeting of alanine/glyoxylate aminotransferase in primary hyperoxaluria type 1. J Cell Biol. 1990 Dec;111(6 Pt 1):2341-51. PMID:1703535
- ↑ Nishiyama K, Funai T, Katafuchi R, Hattori F, Onoyama K, Ichiyama A. Primary hyperoxaluria type I due to a point mutation of T to C in the coding region of the serine:pyruvate aminotransferase gene. Biochem Biophys Res Commun. 1991 May 15;176(3):1093-9. PMID:2039493
- ↑ Purdue PE, Lumb MJ, Allsop J, Minatogawa Y, Danpure CJ. A glycine-to-glutamate substitution abolishes alanine:glyoxylate aminotransferase catalytic activity in a subset of patients with primary hyperoxaluria type 1. Genomics. 1992 May;13(1):215-8. PMID:1349575
- ↑ Minatogawa Y, Tone S, Allsop J, Purdue PE, Takada Y, Danpur CJ, Kido R. A serine-to-phenylalanine substitution leads to loss of alanine:glyoxylate aminotransferase catalytic activity and immunoreactivity in a patient with primary hyperoxaluria type 1. Hum Mol Genet. 1992 Nov;1(8):643-4. PMID:1301173
- ↑ Danpure CJ, Purdue PE, Fryer P, Griffiths S, Allsop J, Lumb MJ, Guttridge KM, Jennings PR, Scheinman JI, Mauer SM, et al.. Enzymological and mutational analysis of a complex primary hyperoxaluria type 1 phenotype involving alanine:glyoxylate aminotransferase peroxisome-to-mitochondrion mistargeting and intraperoxisomal aggregation. Am J Hum Genet. 1993 Aug;53(2):417-32. PMID:8101040
- ↑ von Schnakenburg C, Rumsby G. Primary hyperoxaluria type 1: a cluster of new mutations in exon 7 of the AGXT gene. J Med Genet. 1997 Jun;34(6):489-92. PMID:9192270
- ↑ von Schnakenburg C, Rumsby G. Identification of new mutations in primary hyperoxaluria type 1 (PH1). J Nephrol. 1998 Mar-Apr;11 Suppl 1:15-7. PMID:9604803
- ↑ Amoroso A, Pirulli D, Puzzer D, Ferri L, Crovella S, Ferrettini C, Marangella M, Mazzola G, Florian F. Gene symbol: AGXT. Disease: primary hyperoxaluria type I. Hum Genet. 1999 May;104(5):441. PMID:10394939
- ↑ Pirulli D, Puzzer D, Ferri L, Crovella S, Amoroso A, Ferrettini C, Marangella M, Mazzola G, Florian F. Molecular analysis of hyperoxaluria type 1 in Italian patients reveals eight new mutations in the alanine: glyoxylate aminotransferase gene. Hum Genet. 1999 Jun;104(6):523-5. PMID:10453743
- ↑ Rinat C, Wanders RJ, Drukker A, Halle D, Frishberg Y. Primary hyperoxaluria type I: a model for multiple mutations in a monogenic disease within a distinct ethnic group. J Am Soc Nephrol. 1999 Nov;10(11):2352-8. PMID:10541294
- ↑ Basmaison O, Rolland MO, Cochat P, Bozon D. Identification of 5 novel mutations in the AGXT gene. Hum Mutat. 2000 Jun;15(6):577. PMID:10862087 doi:<577::AID-HUMU9>3.0.CO;2-# 10.1002/1098-1004(200006)15:6<577::AID-HUMU9>3.0.CO;2-#
- ↑ Lumb MJ, Danpure CJ. Functional synergism between the most common polymorphism in human alanine:glyoxylate aminotransferase and four of the most common disease-causing mutations. J Biol Chem. 2000 Nov 17;275(46):36415-22. PMID:10960483 doi:10.1074/jbc.M006693200
- ↑ Coulter-Mackie MB, Tung A, Henderson HE, Toone JR, Applegarth DA. The AGT gene in Africa: a distinctive minor allele haplotype, a polymorphism (V326I), and a novel PH1 mutation (A112D) in Black Africans. Mol Genet Metab. 2003 Jan;78(1):44-50. PMID:12559847
- ↑ Santana A, Salido E, Torres A, Shapiro LJ. Primary hyperoxaluria type 1 in the Canary Islands: a conformational disease due to I244T mutation in the P11L-containing alanine:glyoxylate aminotransferase. Proc Natl Acad Sci U S A. 2003 Jun 10;100(12):7277-82. Epub 2003 May 30. PMID:12777626 doi:10.1073/pnas.1131968100
- ↑ van Woerden CS, Groothoff JW, Wijburg FA, Annink C, Wanders RJ, Waterham HR. Clinical implications of mutation analysis in primary hyperoxaluria type 1. Kidney Int. 2004 Aug;66(2):746-52. PMID:15253729 doi:10.1111/j.1523-1755.2004.00796.x
- ↑ Monico CG, Olson JB, Milliner DS. Implications of genotype and enzyme phenotype in pyridoxine response of patients with type I primary hyperoxaluria. Am J Nephrol. 2005 Mar-Apr;25(2):183-8. Epub 2005 Apr 21. PMID:15849466 doi:10.1159/000085411
- ↑ Frishberg Y, Rinat C, Shalata A, Khatib I, Feinstein S, Becker-Cohen R, Weismann I, Wanders RJ, Rumsby G, Roels F, Mandel H. Intra-familial clinical heterogeneity: absence of genotype-phenotype correlation in primary hyperoxaluria type 1 in Israel. Am J Nephrol. 2005 May-Jun;25(3):269-75. Epub 2005 Jun 15. PMID:15961946 doi:10.1159/000086357
- ↑ Coulter-Mackie MB, Lian Q, Applegarth D, Toone J. The major allele of the alanine:glyoxylate aminotransferase gene: nine novel mutations and polymorphisms associated with primary hyperoxaluria type 1. Mol Genet Metab. 2005 Sep-Oct;86(1-2):172-8. Epub 2005 Jun 15. PMID:15963748 doi:10.1016/j.ymgme.2005.05.005
- ↑ Mesa-Torres N, Fabelo-Rosa I, Riverol D, Yunta C, Albert A, Salido E, Pey AL. The role of protein denaturation energetics and molecular chaperones in the aggregation and mistargeting of mutants causing primary hyperoxaluria type I. PLoS One. 2013 Aug 27;8(8):e71963. doi: 10.1371/journal.pone.0071963. PMID:24205397 doi:http://dx.doi.org/10.1371/journal.pone.0071963
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