title: Metabolic interplay between cytosolic phosphoenolpyruvate carboxylase and mitochondrial alternative oxidase in thermogenic skunk cabbage, Symplocarpus renifolius.
abstract: Skunk cabbage (Symplocarpus renifolius) blooms in early spring and its inflorescence, referred to as the spadix, can produce enough heat to melt snow. Here, we investigated glycolytic carbon flow at the PEP branch-point in thermogenic spadices. Our analyses revealed that petals and pistils in thermogenic florets exhibited higher expression of SrPEPC and SrAOX transcripts than those of SrPK, SrPEPCK, and SrPEPtase. Moreover, enzymatic analyses showed high activities of PEPC in the extracts from thermogenic florets. Finally, mitochondria from thermogenic florets showed low respiratory activities when pyruvate was used as a substrate, although a significant malate-mediated cyanide-insensitive respiration was observed. Collectively, these results suggest that PEP metabolism, primarily catabolized by PEPC, plays a critical role in thermogenesis in S. renifolius.
authors.affiliation: a United Graduate School of Agricultural Science , Iwate University , Ueda, Morioka, Iwate , Japan.
authors.forename: Md Abu
authors.initials: MA
authors.lastname: Sayed
authors.affiliation: a United Graduate School of Agricultural Science , Iwate University , Ueda, Morioka, Iwate , Japan.
authors.forename: Yui
authors.initials: Y
authors.lastname: Umekawa
authors.affiliation: a United Graduate School of Agricultural Science , Iwate University , Ueda, Morioka, Iwate , Japan.|b Cryobiofrontier Research Center , Faculty of Agriculture, Iwate University , Ueda, Morioka, Iwate , Japan.
authors.forename: Kikukatsu
authors.initials: K
authors.lastname: Ito
mesh_terms: D029064:Araceae / Q000201:enzymology* / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology* / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010730:Phosphoenolpyruvate Carboxylase / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D000099188:Alternative Oxidase
chemical_list: D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010730:Phosphoenolpyruvate Carboxylase; D010940:Plant Proteins; D000099188:Alternative Oxidase
keywords: Alternative oxidase; mitochondria; phosphoenolpyruvate carboxylase; respiration; skunk cabbage; thermogenesis