Monovalent Cation Activation of Plant Pyruvate Dehydrogenase Kinase

Schuller, Kathryn A.; Gemel, Joanna; Randall, Douglas D.

doi:10.1104/pp.102.1.139

Cited by 13 publications

(5 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pea seedling PDK activity is stimulated by 5–40 μ m NH 4 + and 10–80 m m K + , but inhibited by 10–100 m m Na + . The NH 4 + decreases the K m for Mg‐ATP by about sixfold [41,43]. Stimulation of PDK activity by NH 4 + is additive with stimulation by K + .…”

Section: Pyruvate Dehydrogenase Kinasementioning

confidence: 99%

Regulation of pyruvate dehydrogenase complex activity in plant cells

Tovar‐Méndez¹,

Miernyk²,

Randall³

2003

European Journal of Biochemistry

268

194

View full text Add to dashboard Cite

The pyruvate dehydrogenase complex (PDC) is subjected to multiple interacting levels of control in plant cells. The first level is subcellular compartmentation. Plant cells are unique in having two distinct, spatially separated forms of the PDC; mitochondrial (mtPDC) and plastidial (plPDC). The mtPDC is the site of carbon entry into the tricarboxylic acid cycle, while the plPDC provides acetyl-CoA and NADH for de novo fatty acid biosynthesis. The second level of regulation of PDC activity is the control of gene expression. The genes encoding the subunits of the mt-and plPDCs are expressed following developmental programs, and are additionally subject to physiological and environmental cues. Thirdly, both the mt-and plPDCs are sensitive to product inhibition, and, potentially, to metabolite effectors. Finally, the two different forms of the complex are regulated by distinct organelle-specific mechanisms. Activity of the mtPDC is regulated by reversible phosphorylation catalyzed by intrinsic kinase and phosphatase components. An additional level of sensitivity is provided by metabolite control of the kinase activity. The plPDC is not regulated by reversible phosphorylation. Instead, activity is controlled to a large extent by the physical environment that exists in the plastid stroma.

show abstract

Section: Pyruvate Dehydrogenase Kinasementioning

confidence: 99%

Regulation of pyruvate dehydrogenase complex activity in plant cells

Tovar‐Méndez¹,

Miernyk²,

Randall³

2003

European Journal of Biochemistry

268

194

View full text Add to dashboard Cite

show abstract

“…40 Furthermore, NH 4 + , produced during photorespiration, is the primary positive regulator of PDK activity. 41 It is feasible to envision instances, however, when there might be specific spatial or temporal demand for an intermediate or product of the Krebs Cycle in the light. Met-oxidized PDC could accommodate this need by inhibiting phosphorylation of PDC E1α by PDK.…”

Section: Discussionmentioning

confidence: 99%

Oxidation of an Adjacent Methionine Residue Inhibits Regulatory Seryl-Phosphorylation of Pyruvate Dehydrogenase

Miernyk

Johnston

Huber

et al. 2009

Proteomics�Insights

View full text Add to dashboard Cite

Abstract:A Met residue is located adjacent to phosphorylation site 1 in the sequences of mitochondrial pyruvate dehydrogenase E1α subunits. When synthetic peptides including site 1 were treated with H 2 O 2 , the Met residue was oxidized to methionine sulfoxide (MetSO), and the peptides were no longer phosphorylated by E1α-kinase. Isolated mitochondria were incubated under state III or IV conditions, lysed, the pyruvate dehydrogenase complex (PDC) immunoprecipitated, and tryptic peptides analyzed by MALDI-TOF mass spectrometry. In all instances both Met and MetSO site 1 tryptic-peptides were detected. Similar results were obtained when suspension-cultured cells were incubated with chemical agents known to stimulate production of reactive oxygen species within the mitochondria. Treatment with these agents had no effect upon the amount of total PDC, but decreased the proportion of P-PDC. We propose that the redox-state of the Met residue adjacent to phosphorylation site 1 of pyruvate dehydrogenase contributes to overall regulation of PDC activity in vivo.

show abstract

“…All of the compounds used as probes of the connection between osmotic stress and phosphorylation of mtPDC were tested for direct effects. Although most monovalent cations activate PDK (Schuller et al 1993), Na + is inhibitory. For this reason, after the initial studies only sorbitol was used as the osmotic stress agent.…”

Section: Discussionmentioning

confidence: 99%

Is there a signal transduction pathway that links events at the plasma membrane to the phosphorylation state of the mitochondrial pyruvate dehydrogenase complex?

Miernyk

Szurmak

Tovar‐Méndez

et al. 2006

Physiologia Plantarum

View full text Add to dashboard Cite

Monoclonal antibodies against the E1a subunit of pyruvate dehydrogenase (PDH) were used to quantify the mitochondrial pyruvate dehydrogenase complex (mtPDC) by enzyme-linked immunosorbent assay (ELISA). Recombinant Arabidopsis thaliana PDH (E1) was used to calibrate the ELISA. Antibodies against a synthetic phosphopeptide corresponding to phosphorylation site one of E1a were used in an ELISA to quantify phospho-PDC (P-PDC). For calibration of the second ELISA, recombinant E1 was phosphorylated in vitro with recombinant A. thaliana E1-kinase. The two ELISA were used to quantify mitochondrial total-and P-PDC in clarified homogenates from Nicotiana tabacum BY-2 suspension cells. The level of mtPDC remained constant throughout the 7-day growth cycle at 25.1 g 21 FW. During the lag (days 0-2) and stationary (day 7) stages of the growth cycle, the mtPDC was completely phosphorylated (inactive), whereas during the log-growth stage it was completely dephosphorylated (active). Exposure of 3-or 7-day posttransfer suspension cells to osmotic stress significantly decreased proportion of P-PDC. A series of pharmacological studies were undertaken to gain insight into the signal transduction pathways coupling osmotic stress perception with control of mitochondrial respiration. Results from these studies indicate a signal transduction pathway linking stress perception to control of mitochondrial respiration that includes protein kinases and phosphoprotein phosphatases.Abbreviations -E1 or PDH, pyruvate dehydrogenase; E2, dihydrolipoyl acetyltransferase; ELISA, enzyme-linked immunosorbent assay; L2, the E2 inner lipoyl domain; mt, mitochondrial; P-, phospho; PDC, pyruvate dehydrogenase complex; PDK, pyruvate dehydrogenase kinase; PDP, pyruvate dehydrogenase phosphatase.

show abstract

Monovalent Cation Activation of Plant Pyruvate Dehydrogenase Kinase

Cited by 13 publications

References 25 publications

Regulation of pyruvate dehydrogenase complex activity in plant cells

Regulation of pyruvate dehydrogenase complex activity in plant cells

Oxidation of an Adjacent Methionine Residue Inhibits Regulatory Seryl-Phosphorylation of Pyruvate Dehydrogenase

Is there a signal transduction pathway that links events at the plasma membrane to the phosphorylation state of the mitochondrial pyruvate dehydrogenase complex?

Contact Info

Product

Resources

About