Biochemical characterization of Arabidopsis APYRASE family reveals their roles in regulating endomembrane NDP/NMP homoeostasis.
Plant apyrases are nucleoside triphosphate (NTP) diphosphohydrolases (NTPDases) and have been implicated in an array of functions within the plant including the regulation of extracellular ATP. Arabidopsis encodes a family of seven membrane bound apyrases (AtAPY1-7) that comprise three distinct clades, all of which contain the five conserved apyrase domains. With the exception of AtAPY1 and AtAPY2, the biochemical and the sub-cellular characterization of the other members are currently unavailable. In this research, we have shown all seven Arabidopsis apyrases localize to internal membranes comprising the cis-Golgi, endoplasmic reticulum (ER) and endosome, indicating an endo-apyrase classification for the entire family. In addition, all members, with the exception of AtAPY7, can function as endo-apyrases by complementing a yeast double mutant (Δynd1Δgda1) which lacks apyrase activity. Interestingly, complementation of the mutant yeast using well characterized human apyrases could only be accomplished by using a functional ER endo-apyrase (NTPDase6), but not the ecto-apyrase (NTPDase1). Furthermore, the substrate specificity analysis for the Arabidopsis apyrases AtAPY1-6 indicated that each member has a distinct set of preferred substrates covering various NDPs (nucleoside diphosphates) and NTPs. Combining the biochemical analysis and sub-cellular localization of the Arabidopsis apyrases family, the data suggest their possible roles in regulating endomembrane NDP/NMP (nucleoside monophosphate) homoeostasis.
Department of Molecular Biosciences, University of Texas, Austin, TX 78713, U.S.A. Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, U.S.A.
Tsan-Yu
TY
Chiu
Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, U.S.A.
Jeemeng
J
Lao
Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, U.S.A.
Bianca
B
Manalansan
Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, U.S.A.
Dominique
D
Loqué
Department of Molecular Biosciences, University of Texas, Austin, TX 78713, U.S.A.
Stanley J
SJ
Roux
Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, U.S.A. ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Victoria 3010, Australia Joshua.heazlewood@unimelb.edu.au.
Joshua L
JL
Heazlewood
D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D001081:Apyrase / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D006056:Golgi Apparatus / Q000378:metabolism; D006706:Homeostasis; D015151:Immunoblotting; D007425:Intracellular Membranes / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D005810:Multigene Family; D010802:Phylogeny; D030821:Plants, Genetically Modified; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D008164:Luminescent Proteins; D029701:Saccharomyces cerevisiae Proteins; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D011755:Pyrophosphatases; C010357:guanosine-diphosphatase; D001081:Apyrase; C506070:Ynd1 protein, S cerevisiae
Arabidopsis apyrase; endomembrane; human; yeast