Functional analysis of mutations in UDP‐galactose‐4‐epimerase (GALE) associated with galactosemia in Korean patients using mammalian GALE‐null cells

Bang, You-Lim; Nguyen, Trang; Trinh, Tram T. B.; Kim, Yun Joong; Song, Junghan; Song, Young-Han

doi:10.1111/j.1742-4658.2009.06922.x

Cited by 23 publications

(18 citation statements)

References 32 publications

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“…A relevant example concerns the in vivo GALE aggregation in type III galactosemia (Bang et al. 2009). Accordingly, the results from the structural analyses of the GALT mutants herein characterized strongly suggest that GALT aggregation associated with protein misfolding might be a major pathogenic mechanism in classic galactosemia, setting the basis for future studies on in vivo GALT aggregation.…”

Section: Discussionmentioning

confidence: 99%

Functional and structural impact of the most prevalent missense mutations in classic galactosemia

Coelho

Trabuco

Ramos

et al. 2014

Molec Gen & Gen Med

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Galactose-1-phosphate uridylyltransferase (GALT) is a key enzyme in galactose metabolism, particularly important in the neonatal period due to ingestion of galactose-containing milk. GALT deficiency results in the genetic disorder classic galactosemia, whose pathophysiology is still not fully elucidated. Whereas classic galactosemia has been hypothesized to result from GALT misfolding, a thorough functional–structural characterization of GALT most prevalent variants was still lacking, hampering the development of alternative therapeutic approaches. The aim of this study was to investigate the structural–functional effects of nine GALT mutations, four of which account for the vast majority of the mutations identified in galactosemic patients. Several methodologies were employed to evaluate the mutations' impact on GALT function, on the protein secondary and tertiary structures, and on the aggregation propensity. The major structural effect concerns disturbed propensity for aggregation, particularly striking for the p.Q188R variant, resulting from the most frequent (∼60%) allele at a worldwide scale. The absence of major effects at the secondary and tertiary structure levels suggests that the disturbed aggregation results from subtle perturbations causing a higher and/or longer exposure of hydrophobic residues in the variants as compared to WT GALT. The results herein described indicate a possible benefit from introducing proteostasis regulators and/or chemical/pharmacological chaperones to prevent the accumulation of protein aggregates, in new avenues of therapeutic research for classic galactosemia.

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Section: Discussionmentioning

confidence: 99%

Functional and structural impact of the most prevalent missense mutations in classic galactosemia

Coelho

Trabuco

Ramos

et al. 2014

Molec Gen & Gen Med

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“…More than 20 different, ostensibly causal genetic variants have been identified in the GALE loci of patients with biochemically confirmed epimerase deficiency; a subset of these alleles and the GALE proteins they encode have been studied in vitro and/or in vivo, revealing a range of degrees and mechanisms of impairment (Alano et al 1998;Bang et al 2009;Chhay et al 2008b;Henderson et al 2001;Maceratesi et al 1996Maceratesi et al , 1998Openo et al 2006;Park et al 2005;Quimby et al 1997;Thoden et al 2001b;Timson 2005;Wohlers and Fridovich-Keil 2000;Wohlers et al 1999). Some variant GALE proteins are catalytically impaired, while others demonstrate compromised stability, at least under defined laboratory conditions.…”

Section: Introductionmentioning

confidence: 99%

A Case Study of Monozygotic Twins Apparently Homozygous for a Novel Variant of UDP-Galactose 4′-epimerase (GALE)

et al. 2012

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Epimerase deficiency galactosemia is an autosomal recessive disorder that results from partial impairment of UDP-galactose 4 0 -epimerase (GALE), the third enzyme in the Leloir pathway of galactose metabolism. Clinical severity of epimerase deficiency ranges from potentially lethal to apparently benign, likely reflecting the extent of GALE enzyme impairment, among other factors. We report here a case study of monozygotic twins identified by newborn screening with elevated total galactose and normal galactose-1P uridylyltransferase (GALT). Follow-up testing revealed partial impairment of GALE in hemolysates but near-normal activity in lymphoblasts; molecular testing identified a missense substitution, R220W, apparently in the homozygous state. The twins were treated with dietary galactose restriction for the first 18 months of life. During this time, independent testing revealed concurrent diagnoses of Williams Syndrome in both twins, and cytomegalovirus (CMV) infection in one. Expression studies of R220W-hGALE in a null-background strain of Saccharomyces cerevisiae demonstrated a very limited impairment of

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“…Another identified protein named UDP-galactose 4-epimerase (GALE) was also down-reg- ulated in thiram treated chondrocytes. GALE protein is an enzyme responsible for the epimerization of UDP-glucose and UDP-N-acetyl glucosamine to UDP-galactose, and UDP-N-acetyl galactosamine, and vice versa (Niou et al, 2009;Bang et al, 2009). GALE plays crucial role in energy metabolism through production of UDP-glucose and UDP-N-acetyl glucosamine necessary for mucopolysaccharide, glycoprotein, glycolipid, and the proteoglycan biosynthesis (Sweeney et al, 1993;Lai et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Effect of thiram on avian growth plate chondrocytes in culture

Rasaputra

Liyanage²,

Lay³

et al. 2013

J. Toxicol. Sci.

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-Thiram is a dithiocarbamate pesticide that causes tibial dyschondroplasia (TD), a growth plate defect, in poultry. Deaths of transitional zone chondrocytes appear to interrupt endochondral bone development leading to the broadening of growth plate. The mechanism of action of thiram on chondrocytes is not well understood. Since proteins play major roles in different aspects of cell's metabolism, growth, and survival, the objective of this study was to find whether thiram produces proteomic changes that could impair the development of chondrocytes. The chondrocytes, isolated from proximal tibial growth plates, were cultured with or without a sub-lethal concentration of thiram for 48 hr, and the cell proteins were extracted, and subjected to 2-D gel electrophoresis. The gel images were compared and statistically evaluated using Melanie software to identify differentially expressed protein spots. Of a total of 72 identifiable spots 3 were down-regulated and 2 up-regulated in thiram treated chondrocytes. In-gel trypsin digestion of the protein spots followed by their characterization by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry identified 25 spots comprising of 23 proteins. Two of 3 down-regulated proteins were identified as a heat shock protein 70 (HSP 70) and a GALE (UDP-galactose-4 epimerase) protein isoform I. The up-regulated proteins were Serpin H1, a protein involved in collagen metabolism and a redox sensor NmrA-like (NMRAL) family domain protein-1. Both GALE and NMRAL proteins are implicated in energy metabolism and redox regulation whereas the HSP 70 protects cells against stress, and implicated in chondrocyte hypertrophy, an important event in endochondral bone formation. The failure of chondrocyte protective mechanisms such as associated with protection against cellular stress and energy metabolism appear to be the likely cause for chondrocyte death induced by thiram.

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Functional analysis of mutations in UDP‐galactose‐4‐epimerase (GALE) associated with galactosemia in Korean patients using mammalian GALE‐null cells

Cited by 23 publications

References 32 publications

Functional and structural impact of the most prevalent missense mutations in classic galactosemia

Functional and structural impact of the most prevalent missense mutations in classic galactosemia

A Case Study of Monozygotic Twins Apparently Homozygous for a Novel Variant of UDP-Galactose 4′-epimerase (GALE)

Effect of thiram on avian growth plate chondrocytes in culture

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