The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity
The family of plant membrane transporters named HKT (for high-affinity K+ transporters) can be subdivided into subfamilies 1 and 2, which, respectively, comprise Na+-selective transporters and transporters able to function as Na+-K+ symporters, at least when expressed in yeast (Saccharomyces cerevisiae) or Xenopus oocytes. Surprisingly, a subfamily 2 member from rice (Oryza sativa), OsHKT2;4, has been proposed to form cation/K+ channels or transporters permeable to Ca2+ when expressed in Xenopus oocytes. Here, OsHKT2;4 functional properties were reassessed in Xenopus oocytes. A Ca2+ permeability through OsHKT2;4 was not detected, even at very low external K+ concentration, as shown by highly negative OsHKT2;4 zero-current potential in high Ca2+ conditions and lack of sensitivity of OsHKT2;4 zero-current potential and conductance to external Ca2+. The Ca2+ permeability previously attributed to OsHKT2;4 probably resulted from activation of an endogenous oocyte conductance. OsHKT2;4 displayed a high permeability to K+ compared with that to Na+ (permeability sequence: K+ . Rb+ _ Cs+ . Na+ _ Li+ _ NH4 +). Examination of OsHKT2;4 current sensitivity to external pH suggested that H+ is not significantly permeant through OsHKT2;4 in most physiological ionic conditions. Further analyses in media containing both Na+ and K+ indicated that OsHKT2;4 functions as K+-selective transporter at low external Na+, but transports also Na+ at high (.10 mM) Na+ concentrations. These data identify OsHKT2;4 as a new functional type in the K+ and Na+-permeable HKT transporter subfamily. Furthermore, the high permeability to K+ in OsHKT2;4 supports the hypothesis that this system is dedicated to K+ transport in the plant.
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Subjects: | F61 - Physiologie végétale - Nutrition, L50 - Physiologie et biochimie animales, F60 - Physiologie et biochimie végétale, Oryza sativa, cytologie, propriété physicochimique, membrane cellulaire, potassium, sodium, calcium, Xenopus laevis, capacité d'échange ionique, http://aims.fao.org/aos/agrovoc/c_5438, http://aims.fao.org/aos/agrovoc/c_2091, http://aims.fao.org/aos/agrovoc/c_1521, http://aims.fao.org/aos/agrovoc/c_9693, http://aims.fao.org/aos/agrovoc/c_6139, http://aims.fao.org/aos/agrovoc/c_7145, http://aims.fao.org/aos/agrovoc/c_1196, http://aims.fao.org/aos/agrovoc/c_49063, http://aims.fao.org/aos/agrovoc/c_24864, |
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dig-cirad-fr-5659002024-01-28T20:47:16Z http://agritrop.cirad.fr/565900/ http://agritrop.cirad.fr/565900/ The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity. Sassi Ali, Mieulet Delphine, Khan Imran, Moreau Bertrand, Gaillard Isabelle, Sentenac Hervé, Very Anne-Aliénor. 2012. Plant Physiology, 160 (1) : 498-510.https://doi.org/10.1104/pp.112.194936 <https://doi.org/10.1104/pp.112.194936> The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity Sassi, Ali Mieulet, Delphine Khan, Imran Moreau, Bertrand Gaillard, Isabelle Sentenac, Hervé Very, Anne-Aliénor eng 2012 Plant Physiology F61 - Physiologie végétale - Nutrition L50 - Physiologie et biochimie animales F60 - Physiologie et biochimie végétale Oryza sativa cytologie propriété physicochimique membrane cellulaire potassium sodium calcium Xenopus laevis capacité d'échange ionique http://aims.fao.org/aos/agrovoc/c_5438 http://aims.fao.org/aos/agrovoc/c_2091 http://aims.fao.org/aos/agrovoc/c_1521 http://aims.fao.org/aos/agrovoc/c_9693 http://aims.fao.org/aos/agrovoc/c_6139 http://aims.fao.org/aos/agrovoc/c_7145 http://aims.fao.org/aos/agrovoc/c_1196 http://aims.fao.org/aos/agrovoc/c_49063 http://aims.fao.org/aos/agrovoc/c_24864 The family of plant membrane transporters named HKT (for high-affinity K+ transporters) can be subdivided into subfamilies 1 and 2, which, respectively, comprise Na+-selective transporters and transporters able to function as Na+-K+ symporters, at least when expressed in yeast (Saccharomyces cerevisiae) or Xenopus oocytes. Surprisingly, a subfamily 2 member from rice (Oryza sativa), OsHKT2;4, has been proposed to form cation/K+ channels or transporters permeable to Ca2+ when expressed in Xenopus oocytes. Here, OsHKT2;4 functional properties were reassessed in Xenopus oocytes. A Ca2+ permeability through OsHKT2;4 was not detected, even at very low external K+ concentration, as shown by highly negative OsHKT2;4 zero-current potential in high Ca2+ conditions and lack of sensitivity of OsHKT2;4 zero-current potential and conductance to external Ca2+. The Ca2+ permeability previously attributed to OsHKT2;4 probably resulted from activation of an endogenous oocyte conductance. OsHKT2;4 displayed a high permeability to K+ compared with that to Na+ (permeability sequence: K+ . Rb+ _ Cs+ . Na+ _ Li+ _ NH4 +). Examination of OsHKT2;4 current sensitivity to external pH suggested that H+ is not significantly permeant through OsHKT2;4 in most physiological ionic conditions. Further analyses in media containing both Na+ and K+ indicated that OsHKT2;4 functions as K+-selective transporter at low external Na+, but transports also Na+ at high (.10 mM) Na+ concentrations. These data identify OsHKT2;4 as a new functional type in the K+ and Na+-permeable HKT transporter subfamily. Furthermore, the high permeability to K+ in OsHKT2;4 supports the hypothesis that this system is dedicated to K+ transport in the plant. article info:eu-repo/semantics/article Journal Article info:eu-repo/semantics/publishedVersion http://agritrop.cirad.fr/565900/1/document_565900.pdf application/pdf Cirad license info:eu-repo/semantics/restrictedAccess https://agritrop.cirad.fr/mention_legale.html https://doi.org/10.1104/pp.112.194936 10.1104/pp.112.194936 info:eu-repo/semantics/altIdentifier/doi/10.1104/pp.112.194936 info:eu-repo/semantics/altIdentifier/purl/https://doi.org/10.1104/pp.112.194936 |
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F61 - Physiologie végétale - Nutrition L50 - Physiologie et biochimie animales F60 - Physiologie et biochimie végétale Oryza sativa cytologie propriété physicochimique membrane cellulaire potassium sodium calcium Xenopus laevis capacité d'échange ionique http://aims.fao.org/aos/agrovoc/c_5438 http://aims.fao.org/aos/agrovoc/c_2091 http://aims.fao.org/aos/agrovoc/c_1521 http://aims.fao.org/aos/agrovoc/c_9693 http://aims.fao.org/aos/agrovoc/c_6139 http://aims.fao.org/aos/agrovoc/c_7145 http://aims.fao.org/aos/agrovoc/c_1196 http://aims.fao.org/aos/agrovoc/c_49063 http://aims.fao.org/aos/agrovoc/c_24864 F61 - Physiologie végétale - Nutrition L50 - Physiologie et biochimie animales F60 - Physiologie et biochimie végétale Oryza sativa cytologie propriété physicochimique membrane cellulaire potassium sodium calcium Xenopus laevis capacité d'échange ionique http://aims.fao.org/aos/agrovoc/c_5438 http://aims.fao.org/aos/agrovoc/c_2091 http://aims.fao.org/aos/agrovoc/c_1521 http://aims.fao.org/aos/agrovoc/c_9693 http://aims.fao.org/aos/agrovoc/c_6139 http://aims.fao.org/aos/agrovoc/c_7145 http://aims.fao.org/aos/agrovoc/c_1196 http://aims.fao.org/aos/agrovoc/c_49063 http://aims.fao.org/aos/agrovoc/c_24864 |
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F61 - Physiologie végétale - Nutrition L50 - Physiologie et biochimie animales F60 - Physiologie et biochimie végétale Oryza sativa cytologie propriété physicochimique membrane cellulaire potassium sodium calcium Xenopus laevis capacité d'échange ionique http://aims.fao.org/aos/agrovoc/c_5438 http://aims.fao.org/aos/agrovoc/c_2091 http://aims.fao.org/aos/agrovoc/c_1521 http://aims.fao.org/aos/agrovoc/c_9693 http://aims.fao.org/aos/agrovoc/c_6139 http://aims.fao.org/aos/agrovoc/c_7145 http://aims.fao.org/aos/agrovoc/c_1196 http://aims.fao.org/aos/agrovoc/c_49063 http://aims.fao.org/aos/agrovoc/c_24864 F61 - Physiologie végétale - Nutrition L50 - Physiologie et biochimie animales F60 - Physiologie et biochimie végétale Oryza sativa cytologie propriété physicochimique membrane cellulaire potassium sodium calcium Xenopus laevis capacité d'échange ionique http://aims.fao.org/aos/agrovoc/c_5438 http://aims.fao.org/aos/agrovoc/c_2091 http://aims.fao.org/aos/agrovoc/c_1521 http://aims.fao.org/aos/agrovoc/c_9693 http://aims.fao.org/aos/agrovoc/c_6139 http://aims.fao.org/aos/agrovoc/c_7145 http://aims.fao.org/aos/agrovoc/c_1196 http://aims.fao.org/aos/agrovoc/c_49063 http://aims.fao.org/aos/agrovoc/c_24864 Sassi, Ali Mieulet, Delphine Khan, Imran Moreau, Bertrand Gaillard, Isabelle Sentenac, Hervé Very, Anne-Aliénor The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity |
description |
The family of plant membrane transporters named HKT (for high-affinity K+ transporters) can be subdivided into subfamilies 1 and 2, which, respectively, comprise Na+-selective transporters and transporters able to function as Na+-K+ symporters, at least when expressed in yeast (Saccharomyces cerevisiae) or Xenopus oocytes. Surprisingly, a subfamily 2 member from rice (Oryza sativa), OsHKT2;4, has been proposed to form cation/K+ channels or transporters permeable to Ca2+ when expressed in Xenopus oocytes. Here, OsHKT2;4 functional properties were reassessed in Xenopus oocytes. A Ca2+ permeability through OsHKT2;4 was not detected, even at very low external K+ concentration, as shown by highly negative OsHKT2;4 zero-current potential in high Ca2+ conditions and lack of sensitivity of OsHKT2;4 zero-current potential and conductance to external Ca2+. The Ca2+ permeability previously attributed to OsHKT2;4 probably resulted from activation of an endogenous oocyte conductance. OsHKT2;4 displayed a high permeability to K+ compared with that to Na+ (permeability sequence: K+ . Rb+ _ Cs+ . Na+ _ Li+ _ NH4 +). Examination of OsHKT2;4 current sensitivity to external pH suggested that H+ is not significantly permeant through OsHKT2;4 in most physiological ionic conditions. Further analyses in media containing both Na+ and K+ indicated that OsHKT2;4 functions as K+-selective transporter at low external Na+, but transports also Na+ at high (.10 mM) Na+ concentrations. These data identify OsHKT2;4 as a new functional type in the K+ and Na+-permeable HKT transporter subfamily. Furthermore, the high permeability to K+ in OsHKT2;4 supports the hypothesis that this system is dedicated to K+ transport in the plant. |
format |
article |
topic_facet |
F61 - Physiologie végétale - Nutrition L50 - Physiologie et biochimie animales F60 - Physiologie et biochimie végétale Oryza sativa cytologie propriété physicochimique membrane cellulaire potassium sodium calcium Xenopus laevis capacité d'échange ionique http://aims.fao.org/aos/agrovoc/c_5438 http://aims.fao.org/aos/agrovoc/c_2091 http://aims.fao.org/aos/agrovoc/c_1521 http://aims.fao.org/aos/agrovoc/c_9693 http://aims.fao.org/aos/agrovoc/c_6139 http://aims.fao.org/aos/agrovoc/c_7145 http://aims.fao.org/aos/agrovoc/c_1196 http://aims.fao.org/aos/agrovoc/c_49063 http://aims.fao.org/aos/agrovoc/c_24864 |
author |
Sassi, Ali Mieulet, Delphine Khan, Imran Moreau, Bertrand Gaillard, Isabelle Sentenac, Hervé Very, Anne-Aliénor |
author_facet |
Sassi, Ali Mieulet, Delphine Khan, Imran Moreau, Bertrand Gaillard, Isabelle Sentenac, Hervé Very, Anne-Aliénor |
author_sort |
Sassi, Ali |
title |
The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity |
title_short |
The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity |
title_full |
The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity |
title_fullStr |
The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity |
title_full_unstemmed |
The Rice monovalent cation transporter OsHKT2;4: Revisited ionic selectivity |
title_sort |
rice monovalent cation transporter oshkt2;4: revisited ionic selectivity |
url |
http://agritrop.cirad.fr/565900/ http://agritrop.cirad.fr/565900/1/document_565900.pdf |
work_keys_str_mv |
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