Properties and Physiological Functions of UDP-Sugar Pyrophosphorylase in<i>Arabidopsis</i>

Kotake, Toshihisa; Hojo, Sachiko; Yamaguchi, Daisuke; Aohara, Tsutomu; Konishi, Tenji; Tsumuraya, Yoichi

doi:10.1271/bbb.60605

Cited by 85 publications

(94 citation statements)

References 34 publications

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“…However, UUAT1 is unlikely to transport significant amounts of UDP-GalA or UDP-Arap in vivo because both UDP-GlcA 4-epimerase and UDP-Xyl 4-epimerase, the enzymes involved in the synthesis of UDP-GalA and UDP-Arap, respectively, are located in the Golgi lumen (Burget et al, 2003;Gu and Bar-Peled, 2004;Mølhøj et al, 2004). A cytosolic salvage pathway for UDPGalA has been reported (Yang et al, 2009) but requires release from the cell wall of GalA, which can then be converted into UDPGalA by the enzymes GalA kinase and Sloppy, a promiscuous UDP-sugar pyrophosphorylase (Kotake et al, 2007). Therefore, this salvage pathway may be active only under certain circumstances and perhaps cytosolic UDP-GalA formed via this pathway could be transported by UUAT1.…”

Section: Discussionmentioning

confidence: 99%

UUAT1 Is a Golgi-Localized UDP-Uronic Acid Transporter That Modulates the Polysaccharide Composition of Arabidopsis Seed Mucilage

et al. 2017

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Section: Discussionmentioning

confidence: 99%

UUAT1 Is a Golgi-Localized UDP-Uronic Acid Transporter That Modulates the Polysaccharide Composition of Arabidopsis Seed Mucilage

et al. 2017

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“…Despite its lower affinity for Ara-1-P, Arabidopsis thaliana USP seems to play a central role in the salvage of this pentose in vivo (21). In Leishmania, however, where D-Ara is present, the monosaccharide is exclusively activated by GDP, and a putative GDP-Ara pyrophosphorylase has been identified in the genome (8).…”

Section: Discussionmentioning

confidence: 99%

“…Like the plant enzyme, T. cruzi USP might be involved in the synthesis of these nucleotide sugars. In Arabidopsis, USP is particularly important in pollination and possibly converts Gal-1-P, Ara-1-P, and Rha-1-P secreted by the pistil (21). In T. cruzi, however, the precise function of the Xyl and Rha metabolism is still unclear.…”

Section: Discussionmentioning

confidence: 99%

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Leishmania UDP-sugar Pyrophosphorylase

Damerow

Lamerz

Haselhorst

et al. 2010

Journal of Biological Chemistry

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The Leishmania parasite glycocalyx is rich in galactosecontaining glycoconjugates that are synthesized by specific glycosyltransferases that use UDP-galactose as a glycosyl donor. UDP-galactose biosynthesis is thought to be predominantly a de novo process involving epimerization of the abundant nucleotide sugar UDP-glucose by the UDP-glucose 4-epimerase, although galactose salvage from the environment has been demonstrated for Leishmania major. Here, we present the characterization of an L. major UDP-sugar pyrophosphorylase able to reversibly activate galactose 1-phosphate into UDP-galactose thus proving the existence of the Isselbacher salvage pathway in this parasite. The ordered bisubstrate mechanism and high affinity of the enzyme for UTP seem to favor the synthesis of nucleotide sugar rather than their pyrophosphorolysis. Although L. major UDP-sugar pyrophosphorylase preferentially activates galactose 1-phosphate and glucose 1-phosphate, the enzyme is able to act on a variety of hexose 1-phosphates as well as pentose 1-phosphates but not hexosamine 1-phosphates and hence presents a broad in vitro specificity. The newly identified enzyme exhibits a low but significant homology with UDP-glucose pyrophosphorylases and conserved in particular is the pyrophosphorylase consensus sequence and residues involved in nucleotide and phosphate binding. Saturation transfer difference NMR spectroscopy experiments confirm the importance of these moieties for substrate binding. The described leishmanial enzyme is closely related to plant UDP-sugar pyrophosphorylases and presents a similar substrate specificity suggesting their common origin.

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“…UDP-Glc pyrophosphorylases generate UDP-Glc, the starting substrate of UDP-sugar metabolism, which is used for the synthesis of cellulose and b-1,3-glucan and for the b-1,4-glucan backbone of xyloglucan (Hayashi et al, 1987;Gordon and Maclachlan, 1989;Cocuron et al, 2007;Park et al, 2010). A plant-specific enzyme, UDP-sugar pyrophosphorylase (USP), converts various monosaccharide 1-Ps to their respective UDP-sugars in the salvage pathway and is required for pollen development (Kotake et al, 2004(Kotake et al, , 2007Schnurr et al, 2006). ADP-Glc pyrophosphorylases provide ADP-Glc for starch synthesis and can be divided into two clades, small (S) subunit and large (L) subunit clades.…”

Section: Introductionmentioning

confidence: 99%

KONJAC1 and 2 Are Key Factors for GDP-Mannose Generation and Affect l-Ascorbic Acid and Glucomannan Biosynthesis in Arabidopsis

et al. 2015

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Humans are unable to synthesize L-ascorbic acid (AsA), yet it is required as a cofactor in many critical biochemical reactions. The majority of human dietary AsA is obtained from plants. In Arabidopsis thaliana, a GDP-mannose pyrophosphorylase (GMPP), VITAMIN C DEFECTIVE1 (VTC1), catalyzes a rate-limiting step in AsA synthesis: the formation of GDP-Man. In this study, we identified two nucleotide sugar pyrophosphorylase-like proteins, KONJAC1 (KJC1) and KJC2, which stimulate the activity of VTC1. The kjc1kjc2 double mutant exhibited severe dwarfism, indicating that KJC proteins are important for growth and development. The kjc1 mutation reduced GMPP activity to 10% of wild-type levels, leading to a 60% reduction in AsA levels. On the contrary, overexpression of KJC1 significantly increased GMPP activity. The kjc1 and kjc1kjc2 mutants also exhibited significantly reduced levels of glucomannan, which is also synthesized from GDP-Man. Recombinant KJC1 and KJC2 enhanced the GMPP activity of recombinant VTC1 in vitro, while KJCs did not show GMPP activity. Yeast two-hybrid assays suggested that the stimulation of GMPP activity occurs via interaction of KJCs with VTC1. These results suggest that KJCs are key factors for the generation of GDP-Man and affect AsA level and glucomannan accumulation through the stimulation of VTC1 GMPP activity.

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Properties and Physiological Functions of UDP-Sugar Pyrophosphorylase inArabidopsis

Cited by 85 publications

References 34 publications

UUAT1 Is a Golgi-Localized UDP-Uronic Acid Transporter That Modulates the Polysaccharide Composition of Arabidopsis Seed Mucilage

UUAT1 Is a Golgi-Localized UDP-Uronic Acid Transporter That Modulates the Polysaccharide Composition of Arabidopsis Seed Mucilage

Leishmania UDP-sugar Pyrophosphorylase

KONJAC1 and 2 Are Key Factors for GDP-Mannose Generation and Affect l-Ascorbic Acid and Glucomannan Biosynthesis in Arabidopsis

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