A novel UDP-glucose transferase is part of the callose synthase complex and interacts with phragmoplastin at the forming cell plate.
Using phragmoplastin as a bait, we isolated an Arabidopsis cDNA encoding a novel UDP-glucose transferase (UGT1). This interaction was confirmed by an in vitro protein--protein interaction assay using purified UGT1 and radiolabeled phragmoplastin. Protein gel blot results revealed that UGT1 is associated with the membrane fraction and copurified with the product-entrapped callose synthase complex. These data suggest that UGT1 may act as a subunit of callose synthase that uses UDP-glucose to synthesize callose, a 1,3-beta-glucan. UGT1 also interacted with Rop1, a Rho-like protein, and this interaction occurred only in its GTP-bound configuration, suggesting that the plant callose synthase may be regulated by Rop1 through the interaction with UGT1. The green fluorescent protein--UGT1 fusion protein was located on the forming cell plate during cytokinesis. We propose that UGT1 may transfer UDP-glucose from sucrose synthase to the callose synthase and thus help form a substrate channel for the synthesis of callose at the forming cell plate.
Department of Molecular Genetics and Plant Biotechnology Center, Ohio State University, 1060 Carmack Road, Columbus, Ohio 43210-1002, USA.
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Hong
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Zhang
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Olson
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Verma
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division; D002458:Cell Fractionation; D002473:Cell Wall / Q000378:metabolism; D018076:DNA, Complementary / Q000302:isolation & purification; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D020798:Two-Hybrid System Techniques
D018076:DNA, Complementary; D008164:Luminescent Proteins; D008565:Membrane Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; D049452:Green Fluorescent Proteins; C098512:phragmoplastin protein, plant; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase