start-ver=1.4 cd-journal=joma no-vol=6 cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2015 dt-pub=20150105 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=AtPHT4;4 is a chloroplast-localized ascorbate transporter in Arabidopsis en-subtitle= kn-subtitle= en-abstract= kn-abstract=Ascorbate is an antioxidant and coenzyme for various metabolic reactions in vivo. In plant chloroplasts, high ascorbate levels are required to overcome photoinhibition caused by strong light. However, ascorbate is synthesized in the mitochondria and the molecular mechanisms underlying ascorbate transport into chloroplasts are unknown. Here we show that AtPHT4;4, a member of the phosphate transporter 4 family of Arabidopsis thaliana, functions as an ascorbate transporter. In vitro analysis shows that proteoliposomes containing the purified AtPHT4;4 protein exhibit membrane potential- and Cl-dependent ascorbate uptake. The AtPHT4;4 protein is abundantly expressed in the chloroplast envelope membrane. Knockout of AtPHT4;4 results in decreased levels of the reduced form of ascorbate in the leaves and the heat dissipation process of excessive energy during photosynthesis is compromised. Taken together, these observations indicate that the AtPHT4;4 protein is an ascorbate transporter at the chloroplast envelope membrane, which may be required for tolerance to strong light stress. en-copyright= kn-copyright= en-aut-name=MiyajiTakaaki en-aut-sei=Miyaji en-aut-mei=Takaaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KuromoriTakashi en-aut-sei=Kuromori en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TakeuchiYu en-aut-sei=Takeuchi en-aut-mei=Yu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YokoshoKengo en-aut-sei=Yokosho en-aut-mei=Kengo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=ShimazawaAtsushi en-aut-sei=Shimazawa en-aut-mei=Atsushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SugimotoEriko en-aut-sei=Sugimoto en-aut-mei=Eriko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=OmoteHiroshi en-aut-sei=Omote en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=ShinozakiKazuo en-aut-sei=Shinozaki en-aut-mei=Kazuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=MoriyamaYoshinori en-aut-sei=Moriyama en-aut-mei=Yoshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil= kn-affil=Advanced Science Research Center, Okayama University affil-num=2 en-affil= kn-affil=Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science affil-num=3 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=4 en-affil= kn-affil=Institute of Plant Science and Resources, Okayama University affil-num=5 en-affil= kn-affil=Institute of Plant Science and Resources, Okayama University affil-num=6 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=7 en-affil= kn-affil=Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science affil-num=8 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=9 en-affil= kn-affil=Institute of Plant Science and Resources, Okayama University affil-num=10 en-affil= kn-affil=Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science affil-num=11 en-affil= kn-affil=Advanced Science Research Center, Okayama University END start-ver=1.4 cd-journal=joma no-vol=4 cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2014 dt-pub=20141030 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Identification of a mammalian vesicular polyamine transporter en-subtitle= kn-subtitle= en-abstract= kn-abstract=Spermine and spermidine act as neuromodulators upon binding to the extracellular site(s) of various ionotropic receptors, such as N-methyl-d-aspartate receptors. To gain access to the receptors, polyamines synthesized in neurons and astrocytes are stored in secretory vesicles and released upon depolarization. Although vesicular storage is mediated in an ATP-dependent, reserpine-sensitive fashion, the transporter responsible for this process remains unknown. SLC18B1 is the fourth member of the SLC18 transporter family, which includes vesicular monoamine transporters and vesicular acetylcholine transporter. Proteoliposomes containing purified human SLC18B1 protein actively transport spermine and spermidine by exchange of H+. SLC18B1 protein is predominantly expressed in the hippocampus and is associated with vesicles in astrocytes. SLC18B1 gene knockdown decreased both SLC18B1 protein and spermine/spermidine contents in astrocytes. These results indicated that SLC18B1 encodes a vesicular polyamine transporter (VPAT). en-copyright= kn-copyright= en-aut-name=HiasaMiki en-aut-sei=Hiasa en-aut-mei=Miki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyajiTakaaki en-aut-sei=Miyaji en-aut-mei=Takaaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HarunaYuka en-aut-sei=Haruna en-aut-mei=Yuka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TakeuchiTomoya en-aut-sei=Takeuchi en-aut-mei=Tomoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HaradaYuika en-aut-sei=Harada en-aut-mei=Yuika kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MoriyamaSawako en-aut-sei=Moriyama en-aut-mei=Sawako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamamotoAkitsugu en-aut-sei=Yamamoto en-aut-mei=Akitsugu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=OmoteHiroshi en-aut-sei=Omote en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=MoriyamaYoshinori en-aut-sei=Moriyama en-aut-mei=Yoshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=2 en-affil= kn-affil=Advanced Science Research Center, Okayama University affil-num=3 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=4 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=5 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=6 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=7 en-affil= kn-affil=Faculty of Bioscience, Nagahama Institute of Bio-science and Technology affil-num=8 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=9 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences END start-ver=1.4 cd-journal=joma no-vol=105 cd-vols= no-issue=15 article-no= start-page=5683 end-page=5686 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080401 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Identification of a vesicular nucleotide transporter en-subtitle= kn-subtitle= en-abstract= kn-abstract=

ATP is a major chemical transmitter in purinergic signal transmission. Before secretion, ATP is stored in secretory vesicles found in purinergic cells. Although the presence of active transport mechanisms for ATP has been postulated for a long time, the proteins responsible for its vesicular accumulation remains unknown. The transporter encoded by the human and mouse SLC17A9 gene, a novel member of an anion transporter family, was predominantly expressed in the brain and adrenal gland. The mouse and bovine counterparts were associated with adrenal chromaffin granules. Proteoliposomes containing purified transporter actively took up ATP, ADP, and GTP by using membrane potential as the driving force. The uptake properties of the reconstituted transporter were similar to that of the ATP uptake by synaptic vesicles and chromaffin granules. Suppression of endogenous SLC17A9 expression in PC12 cells decreased exocytosis of ATP. These findings strongly suggest that SLC17A9 protein is a vesicular nucleotide transporter and should lead to the elucidation of the molecular mechanism of ATP secretion in purinergic signal transmission.

en-copyright= kn-copyright= en-aut-name=SawadaKeisuke en-aut-sei=Sawada en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=EchigoNoriko en-aut-sei=Echigo en-aut-mei=Noriko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=JugeNarinobu en-aut-sei=Juge en-aut-mei=Narinobu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyajiTakaaki en-aut-sei=Miyaji en-aut-mei=Takaaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=OtsukaMasato en-aut-sei=Otsuka en-aut-mei=Masato kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=OmoteHiroshi en-aut-sei=Omote en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamamotoAkitsugu en-aut-sei=Yamamoto en-aut-mei=Akitsugu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=MoriyamaYoshinori en-aut-sei=Moriyama en-aut-mei=Yoshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama University affil-num=4 en-affil= kn-affil=Okayama University affil-num=5 en-affil= kn-affil=Okayama University affil-num=6 en-affil= kn-affil=Okayama University affil-num=7 en-affil= kn-affil=Nagahama Institute of Technology affil-num=8 en-affil= kn-affil=Okayama University en-keyword=chromaffin granule kn-keyword=chromaffin granule en-keyword=synaptic vesicle kn-keyword=synaptic vesicle en-keyword=ATP kn-keyword=ATP en-keyword=storage and exocytosis kn-keyword=storage and exocytosis en-keyword=purinergic signaling. kn-keyword=purinergic signaling. END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2009 dt-pub=20090325 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=小胞型アスパラギン酸トランスポーターの発見とその生理的意義について en-subtitle= kn-subtitle= en-abstract= kn-abstract= en-copyright= kn-copyright= en-aut-name=MiyajiTakaaki en-aut-sei=Miyaji en-aut-mei=Takaaki kn-aut-name=宮地孝明 kn-aut-sei=宮地 kn-aut-mei=孝明 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 END