Disruption and mutagenesis of the Saccharomyces cerevisiae PDX1 gene encoding the protein X component of the pyruvate dehydrogenase complex

Lawson, Janet E.; Behal, Robert H.; Reed, Lester J.

doi:10.1021/bi00225a015

Cited by 73 publications

(76 citation statements)

References 33 publications

(41 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In mammals, PDC exists in a dodecahedral form with 60 monomers of E2 as a core unit, surrounded by 30 E1 heterodimers (E1␣ and E1␤) and six E3 homodimers (Reed, 1998). Yeast (Saccharomyces cerevisiae) and mammalian PDC also contain an E3 binding protein that is implicated in stabilizing the complex (Lawson et al, 1991;Stoops et al, 1997).…”

mentioning

confidence: 99%

Characterization of Two cDNAs Encoding Mitochondrial Lipoamide Dehydrogenase from Arabidopsis

Lutziger

Oliver

2001

Plant Physiology

View full text Add to dashboard Cite

In contrast to peas (Pisum sativum), where mitochondrial lipoamide dehydrogenase is encoded by a single gene and shared between the α-ketoacid dehydrogenase complexes and the Gly decarboxylase complex, Arabidopsis has two genes encoding for two mitochondrial lipoamide dehydrogenases. Northern-blot analysis revealed different levels of RNA expression for the two genes in different organs; mtLPD1 had higher RNA levels in green leaves compared with the much lower level in roots. The mRNA formtLPD2 shows the inverse pattern. The other organs examined showed nearly equal RNA expressions for both genes. Analysis of etiolated seedlings transferred to light showed a strong induction of RNA expression for mtLPD1 but only a moderate induction of mtLPD2. Based on the organ and light-dependent expression patterns, we hypothesize thatmtLPD1 encodes the protein most often associated with the Gly decarboxylase complex, and mtLPD2 encodes the protein incorporated into α-ketoacid dehydrogenase complexes. Due to the high level of sequence conservation between the two mtLPDs, we assume that the proteins, once in the mitochondrial matrix, are interchangeable among the different multienzyme complexes. If present at high levels, one mtLPD might substitute for the other. Supporting this hypothesis are results obtained with a T-DNA knockout mutant,mtlpd2, which shows no apparent phenotypic change under laboratory growth conditions. This indicates that mtLPD1 can substitute for mtLPD2 and associate with all these multienzyme complexes.

show abstract

mentioning

confidence: 99%

Characterization of Two cDNAs Encoding Mitochondrial Lipoamide Dehydrogenase from Arabidopsis

Lutziger

Oliver

2001

Plant Physiology

View full text Add to dashboard Cite

show abstract

“…Section 1734 solely to indicate this fact. most eukaryotes is a lower abundance polypeptide termed protein X (17)(18)(19).…”

mentioning

confidence: 99%

“…Protein X from Ascaris suum, in contrast, does not contain a lipoyl domain (22). A characteristic common to all protein X subunits is that they can bind the E3 component with higher affinity than the E2 core, suggesting a possible function for this protein and prompting it being renamed the E3-binding protein (17)(18)(19)22). While it is clear that E3-binding proteins are present in animal and fungal PDCs, evidence for an E3-binding protein in plants is indirect and has not yet been confirmed (23).…”

mentioning

confidence: 99%

The Dihydrolipoamide S-Acetyltransferase Subunit of the Mitochondrial Pyruvate Dehydrogenase Complex from Maize Contains a Single Lipoyl Domain

Thelen¹,

Muszynski²,

David³

et al. 1999

Journal of Biological Chemistry

View full text Add to dashboard Cite

Immunoanalysis of mitochondrial proteins from various plants, using a monoclonal antibody against the maize E2, revealed 50 -54-kDa cross-reacting polypeptides in all samples. A larger protein (76 kDa) was also recognized in an enriched pea mitochondrial PDC preparation, indicating two distinct E2s. The presence of a single lipoyl-domain E2 in Arabidopsis thaliana was confirmed by identifying a gene encoding a hypothetical protein with 62% amino acid identity to the maize homologue. These data suggest that all plant mitochondrial PDCs contain an E2 with a single lipoyl domain. Additionally, A. thaliana and other dicots possess a second E2, which contains two lipoyl domains and is only 33% identical at the amino acid level to the smaller isoform. The reason two distinct E2s exist in dicotyledon plants is uncertain, although the variability between these isoforms, particularly within the subunit-binding domain, suggests different roles in assembly and/or function of the plant mitochondrial PDC.

show abstract

“…The E3 component, encoded by the LPD1 gene, is also a component in the 2-oxoglutarate dehydrogenase and glycine decarboxylase complexes (34). The protein X (encoded by the PDX1 gene) plays a structural role in the PDC; it binds and positions E3 to the E2 core (52). Deleting any genes in PDC resulted in defects in generating acetyl-CoA (34).…”

Section: Resultsmentioning

confidence: 99%

The Dihydrolipoamide Acetyltransferase Is a Novel Metabolic Longevity Factor and Is Required for Calorie Restriction-mediated Life Span Extension

Easlon

Tsang

Dilova

et al. 2007

Journal of Biological Chemistry

View full text Add to dashboard Cite

Calorie restriction (CR) extends life span in a wide variety of species. Recent studies suggest that an increase in mitochondrial metabolism mediates CR-induced life span extension. Here we present evidence that Lat1 (dihydrolipoamide acetyltransferase), the E2 component of the mitochondrial pyruvate dehydrogenase complex, is a novel metabolic longevity factor in the CR pathway. Deleting the LAT1 gene abolishes life span extension induced by CR. Overexpressing Lat1 extends life span, and this life span extension is not further increased by CR. Similar to CR, life span extension by Lat1 overexpression largely requires mitochondrial respiration, indicating that mitochondrial metabolism plays an important role in CR. Interestingly, Lat1 overexpression does not require the Sir2 family to extend life span, suggesting that Lat1 mediates a branch of the CR pathway that functions in parallel to the Sir2 family. Lat1 is also a limiting longevity factor in nondividing cells in that overexpressing Lat1 extends cell survival during prolonged culture at stationary phase. Our studies suggest that Lat1 overexpression extends life span by increasing metabolic fitness of the cell. CR may therefore also extend life span and ameliorate age-associated diseases by increasing metabolic fitness through regulating central metabolic enzymes. Calorie restriction (CR)2 is the most effective intervention known to extend life span in a variety of species, including mammals (1, 2). CR has also been shown to delay the onset or reduce the incidence of many age-related diseases (1). Although it has been suggested that CR may work by reducing the levels of reactive oxygen species due to a slowing in metabolism (1, 3), the mechanism by which CR extends life span and ameliorates age-associated diseases is still uncertain.Moderate CR can be imposed in the budding yeast Saccharomyces cerevisiae by reducing the glucose concentration from 2 to 0.5% in rich media (4 -9). Under this CR condition, the growth rate remains robust, and yeast mother cells show an extended replicative life span (division potential) of about 20 -30%. Variations in CR protocols have been described where limitation of amino acids and other nutrients accompanies carbon source limitation (10, 11). These regimens may represent another possible longevity pathway that functions in parallel to CR in rich media. Genetic models of CR have also been identified and studied in multiple strain backgrounds, such as PSY316 (4, 5, 7), W303 (4, 8, 9, 12), and BY4742 (13). These CR mimics include a hexokinase mutant (hxk2⌬) and mutations that down-regulate the glucose-sensing cyclic-AMP/protein kinase A pathway: the temperature-sensitive alleles of the adenylate cyclase (cdc35-1) or the RAS nucleotide exchange protein (cdc25-10) and deletions of the glucose-sensing protein Gpa2 and Gpr1. Additional CR genetic models, the tor1⌬ and sch9⌬ mutants, have recently been reported to extend yeast life span (14, 15). The nutrient-sensing Target of Rapamycin (TOR) pathway and Sch9 kinase (a homolog of the...

show abstract

Disruption and mutagenesis of the Saccharomyces cerevisiae PDX1 gene encoding the protein X component of the pyruvate dehydrogenase complex

Cited by 73 publications

References 33 publications

Characterization of Two cDNAs Encoding Mitochondrial Lipoamide Dehydrogenase from Arabidopsis

Characterization of Two cDNAs Encoding Mitochondrial Lipoamide Dehydrogenase from Arabidopsis

The Dihydrolipoamide S-Acetyltransferase Subunit of the Mitochondrial Pyruvate Dehydrogenase Complex from Maize Contains a Single Lipoyl Domain

The Dihydrolipoamide Acetyltransferase Is a Novel Metabolic Longevity Factor and Is Required for Calorie Restriction-mediated Life Span Extension

Contact Info

Product

Resources

About