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=2025 dt-pub=20250603 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Amino Acid Substitutions in Loop C of Arabidopsis PIP2 Aquaporins Alters the Permeability of CO2 en-subtitle= kn-subtitle= en-abstract= kn-abstract=The transport of CO2 across biomembranes in plant cells is essential for efficient photosynthesis. Some aquaporins capable of CO2 transport, referred to as ‘COOporins’, are postulated to play a crucial role in leaf CO2 diffusion. However, the structural basis of CO2 permeation through aquaporins remains largely unknown. Here, we show that amino acids in loop C are critical for the CO2 permeability of Arabidopsis thaliana PIP2 aquaporins. We found that swapping tyrosine and serine in loop C to histidine and phenylalanine, which differ between AtPIP2;1 and AtPIP2;3, altered CO2 permeability when examined in the Xenopus laevis oocyte heterologous expression system. AlphaFold2 modelling indicated that these substitution induced a conformational shift in the sidechain of arginine in the aromatic/arginine (ar/R) selectivity filter and in lysine at the extracellular mouth of the monomeric pore in PIP2 aquaporins. Our findings demonstrate that distal amino acid substitutions can trigger conformational changes of the ar/R filter in the monomeric pore, modulating CO2 permeability. Additionally, phylogenetic analysis suggested that aquaporins capable of dual water/CO2 permeability are ancestral to those that are water-selective and CO2-impermeable, and CO2-selective and water impermeable. en-copyright= kn-copyright= en-aut-name=TaniaShaila Shermin en-aut-sei=Tania en-aut-mei=Shaila Shermin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=UtsugiShigeko en-aut-sei=Utsugi en-aut-mei=Shigeko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TsuchiyaYoshiyuki en-aut-sei=Tsuchiya en-aut-mei=Yoshiyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SasanoShizuka en-aut-sei=Sasano en-aut-mei=Shizuka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KatsuharaMaki en-aut-sei=Katsuhara en-aut-mei=Maki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MoriIzumi C. en-aut-sei=Mori en-aut-mei=Izumi C. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=4 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=5 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=6 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=Arabidopsis thaliana kn-keyword=Arabidopsis thaliana en-keyword=CO2 transport kn-keyword=CO2 transport en-keyword=monomeric pore kn-keyword=monomeric pore en-keyword=PIP2 aquaporin kn-keyword=PIP2 aquaporin en-keyword=Xenopus laevis kn-keyword=Xenopus laevis END start-ver=1.4 cd-journal=joma no-vol=227 cd-vols= no-issue= article-no= start-page=110168 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=202510 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The hidden cation-selective pore in ion-conducting aquaporin OsPIP2;4 from rice en-subtitle= kn-subtitle= en-abstract= kn-abstract=Ion-conducting aquaporins (icAQPs) transport ions as well as water. Although the molecular mechanism of how AQPs establish selective permeability for water molecules is well understood, the ion-transporting mechanism in icAQPs has not yet been fully elucidated. In this study, we investigated the molecular mechanism of cation transport in OsPIP2;4, an icAQP in rice, by homology modeling and the electrophysiological analysis using Xenopus laevis oocytes. Water and ion transport assays using OsPIP2;4 T227M and G278K mutants strongly suggested that water- and cation-transporting pathways are independent of each other. Data from amino acid substitutions V54I and A143G in OsPIP2;4 led to the identification of a novel hidden pathway for cation transport located on the side surfaces of the tetramer channel, where two protomers are in contact, which is distinct from conventional monomeric pores and the tetrameric central pore in AQPs. Moreover, the present results provide the possibility that this hypothetical hidden pore also functions in the barley icAQP HvPIP2;8. The overall structure of this novel pathway appears to differ from the structure of general cation channels. However, the arrangement of hydrophilic amino acids at the entrance of the pathway of OsPIP2;4 was found to be comparable to that of some cation channels, which implies that the molecular mechanism of dehydration of hydrated ions might resemble that of the channels. Although direct structural evidence is needed to confirm the proposed pathway, the present study can be a stepping stone toward unraveling the mechanism of dual water and ion transport through icAQPs in plants. en-copyright= kn-copyright= en-aut-name=OnoShuntaro en-aut-sei=Ono en-aut-mei=Shuntaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TranSen Thi Huong en-aut-sei=Tran en-aut-mei=Sen Thi Huong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SaitohYasunori en-aut-sei=Saitoh en-aut-mei=Yasunori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UtsugiShigeko en-aut-sei=Utsugi en-aut-mei=Shigeko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HorieTomoaki en-aut-sei=Horie en-aut-mei=Tomoaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KatsuharaMaki en-aut-sei=Katsuhara en-aut-mei=Maki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=4 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=5 en-affil=Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University kn-affil= affil-num=6 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=Rice kn-keyword=Rice en-keyword=Barley kn-keyword=Barley en-keyword=Ion transport kn-keyword=Ion transport en-keyword=Ion-conducting aquaporin (icAQP) kn-keyword=Ion-conducting aquaporin (icAQP) en-keyword=Plasma membrane intrinsic protein (PIP) kn-keyword=Plasma membrane intrinsic protein (PIP) END start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=12 article-no= start-page=1842 end-page=1846 dt-received= dt-revised= dt-accepted= dt-pub-year=2012 dt-pub=201212 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Functional characterization of a novel plasma membrane intrinsic protein2 in barley en-subtitle= kn-subtitle= en-abstract= kn-abstract=Water homeostasis is crucial to the growth and survival of plants. Plasma membrane intrinsic proteins (PIPs) have been shown to be primary channels mediating water uptake in plant cells. We characterized a novel PIP2 gene, HvPIP2;8 in barley (Hordeum vulgare). HvPIP2;8 shared 72?76% identity with other HvPIP2s and 74% identity with rice OsPIP2;8. The gene was expressed in all organs including the shoots, roots and pistil at a similar level. When HvPIP2;8 was transiently expressed in onion epidermal cells, it was localized to the plasma membrane. HvPIP2;8 showed transport activity for water in Xenopus oocytes, however its interaction with HvPIP1;2 was not observed. These results suggest that HvPIP2;8 plays a role in water homeostasis although further functional analysis is required in future. en-copyright= kn-copyright= en-aut-name=ShibasakaMineo en-aut-sei=Shibasaka en-aut-mei=Mineo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SasanoSizuka en-aut-sei=Sasano en-aut-mei=Sizuka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UtsugiSigeko en-aut-sei=Utsugi en-aut-mei=Sigeko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KatsuharaMaki en-aut-sei=Katsuhara en-aut-mei=Maki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Institute of Plant Science and Resources; Okayama University affil-num=2 en-affil= kn-affil=Institute of Plant Science and Resources; Okayama University affil-num=3 en-affil= kn-affil=Institute of Plant Science and Resources; Okayama University affil-num=4 en-affil= kn-affil=Institute of Plant Science and Resources; Okayama University en-keyword=aquaporin kn-keyword=aquaporin en-keyword=plasma membrane intrinsic protein kn-keyword=plasma membrane intrinsic protein en-keyword=PIP kn-keyword=PIP en-keyword=HvPIP2;8 kn-keyword=HvPIP2;8 en-keyword=water transport kn-keyword=water transport en-keyword=barley kn-keyword=barley en-keyword=Hordeum vulgare kn-keyword=Hordeum vulgare en-keyword=Xenopus laevis oocytes kn-keyword=Xenopus laevis oocytes END start-ver=1.4 cd-journal=joma no-vol=31 cd-vols= no-issue= article-no= start-page=21 end-page=25 dt-received= dt-revised= dt-accepted= dt-pub-year=2009 dt-pub=200912 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Cooling effect on buildings by the roof greening at Research Institute for Bioresources, Okayama University kn-title=岡山大学資源生物科学研究所における屋上緑化による建物冷却効果 en-subtitle= kn-subtitle= en-abstract= kn-abstract=Roof greening is known to be environmentally friendly technology. Recently developed new roof greening systems, such as the thin-layer/Excel soil? system and the wetland type greening system, were tested at the roof top of buildings of Research Institute for Bioresources, Okayama University. After a multi-year test, these new systems have been established during high-temperature and less-rainfall summer seasons in the south Okayama region. Data indicated that roof greening effectively reduced the temperature of the concrete surface (more than 10°C). The room temperature under the green roof was also reduced both in a stock room (up to 6°C) and in an office room (about 2°C). We also provided the estimation indicating that this roof greening is useful for the decrease in CO(2) emission through the reduction of the electric power for air-conditioning in the summer. en-copyright= kn-copyright= en-aut-name=KatsuharaMaki en-aut-sei=Katsuhara en-aut-mei=Maki kn-aut-name=且原真木 kn-aut-sei=且原 kn-aut-mei=真木 aut-affil-num=1 ORCID= en-aut-name=TanakamaruShigemi en-aut-sei=Tanakamaru en-aut-mei=Shigemi kn-aut-name=田中丸重美 kn-aut-sei=田中丸 kn-aut-mei=重美 aut-affil-num=2 ORCID= en-aut-name=MoriIzumi C. en-aut-sei=Mori en-aut-mei=Izumi C. kn-aut-name=森泉 kn-aut-sei=森 kn-aut-mei=泉 aut-affil-num=3 ORCID= en-aut-name=TaniAkio en-aut-sei=Tani en-aut-mei=Akio kn-aut-name=谷明生 kn-aut-sei=谷 kn-aut-mei=明生 aut-affil-num=4 ORCID= en-aut-name=UtsugiShigeko en-aut-sei=Utsugi en-aut-mei=Shigeko kn-aut-name=宇都木繁子 kn-aut-sei=宇都木 kn-aut-mei=繁子 aut-affil-num=5 ORCID= en-aut-name=EnomotoTakashi en-aut-sei=Enomoto en-aut-mei=Takashi kn-aut-name=榎本敬 kn-aut-sei=榎本 kn-aut-mei=敬 aut-affil-num=6 ORCID= en-aut-name=MaitaniToshihiko en-aut-sei=Maitani en-aut-mei=Toshihiko kn-aut-name=米谷俊彦 kn-aut-sei=米谷 kn-aut-mei=俊彦 aut-affil-num=7 ORCID= affil-num=1 en-affil= kn-affil=岡山大学資源生物科学研究所 affil-num=2 en-affil= kn-affil=岡山大学資源生物科学研究所 affil-num=3 en-affil= kn-affil=岡山大学資源生物科学研究所 affil-num=4 en-affil= kn-affil=岡山大学資源生物科学研究所 affil-num=5 en-affil= kn-affil=岡山大学資源生物科学研究所 affil-num=6 en-affil= kn-affil=岡山大学資源生物科学研究所 affil-num=7 en-affil= kn-affil=岡山大学資源生物科学研究所 en-keyword=Roof greening kn-keyword=Roof greening en-keyword=wetland type greening kn-keyword=wetland type greening en-keyword=thin-Iayer/ Excel soil? system kn-keyword=thin-Iayer/ Excel soil? system en-keyword=cooling effect kn-keyword=cooling effect 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=1998 dt-pub=19980930 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Arabidopsis thalianaにおける花器で特異的に発現する遺伝子の分子生物学的研究 kn-title=MOLECULAR BIOLOGICAL STUDY ON FLOWER-SPECIFIC GENES IN ARABIDOPSIS THALIANA en-subtitle= kn-subtitle= en-abstract= kn-abstract= en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=宇都木繁子 kn-aut-sei=宇都木 kn-aut-mei=繁子 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 END