PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry

Many plasma membrane channels form oligomeric assemblies, and heterooligomerization has been described as a distinctive feature of some protein families. In the particular case of plant plasma membrane aquaporins (PIPs), PIP1 and PIP2 monomers interact to form heterotetramers. However, the biologica...

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Autores principales:	Sigaut, Lorena, Soto, Gabriela Cynthia, Ayub, Nicolás Daniel
Publicado:	2016
Materias:	aquaporin plant protein proton water animal cell membrane cell membrane permeability chemistry metabolism osmosis pH protein multimerization transport at the cellular level Xenopus laevis Animals Aquaporins Biological Transport Cell Membrane Cell Membrane Permeability Hydrogen-Ion Concentration Osmosis Plant Proteins Protein Multimerization Protons Water
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00063495_v110_n6_p1312_Jozefkowicz http://hdl.handle.net/20.500.12110/paper_00063495_v110_n6_p1312_Jozefkowicz
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00063495_v110_n6_p1312_Jozefkowicz
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spelling	paper:paper_00063495_v110_n6_p1312_Jozefkowicz2023-06-08T14:31:15Z PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry Sigaut, Lorena Soto, Gabriela Cynthia Ayub, Nicolás Daniel aquaporin plant protein proton water animal cell membrane cell membrane permeability chemistry metabolism osmosis pH protein multimerization transport at the cellular level Xenopus laevis Animals Aquaporins Biological Transport Cell Membrane Cell Membrane Permeability Hydrogen-Ion Concentration Osmosis Plant Proteins Protein Multimerization Protons Water Xenopus laevis Many plasma membrane channels form oligomeric assemblies, and heterooligomerization has been described as a distinctive feature of some protein families. In the particular case of plant plasma membrane aquaporins (PIPs), PIP1 and PIP2 monomers interact to form heterotetramers. However, the biological properties of the different heterotetrameric configurations formed by PIP1 and PIP2 subunits have not been addressed yet. Upon coexpression of tandem PIP2-PIP1 dimers in Xenopus oocytes, we can address, for the first time to our knowledge, the functional properties of single heterotetrameric species having 2:2 stoichiometry. We have also coexpressed PIP2-PIP1 dimers with PIP1 and PIP2 monomers to experimentally investigate the localization and biological activity of each tetrameric assembly. Our results show that PIP2-PIP1 heterotetramers can assemble with 3:1, 1:3, or 2:2 stoichiometry, depending on PIP1 and PIP2 relative expression in the cell. All PIP2-PIP1 heterotetrameric species localize at the plasma membrane and present the same water transport capacity. Furthermore, the contribution of any heterotetrameric assembly to the total water transport through the plasma membrane doubles the contribution of PIP2 homotetramers. Our results also indicate that plasma membrane water transport can be modulated by the coexistence of different tetrameric species and by intracellular pH. Moreover, all the tetrameric species present similar cooperativity behavior for proton sensing. These findings throw light on the functional properties of PIP tetramers, showing that they have flexible stoichiometry dependent on the quantity of PIP1 and PIP2 molecules available. This represents, to our knowledge, a novel regulatory mechanism to adjust water transport across the plasma membrane. © 2016 Biophysical Society. Fil:Sigaut, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Soto, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ayub, N. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2016 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00063495_v110_n6_p1312_Jozefkowicz http://hdl.handle.net/20.500.12110/paper_00063495_v110_n6_p1312_Jozefkowicz
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	aquaporin plant protein proton water animal cell membrane cell membrane permeability chemistry metabolism osmosis pH protein multimerization transport at the cellular level Xenopus laevis Animals Aquaporins Biological Transport Cell Membrane Cell Membrane Permeability Hydrogen-Ion Concentration Osmosis Plant Proteins Protein Multimerization Protons Water Xenopus laevis
spellingShingle	aquaporin plant protein proton water animal cell membrane cell membrane permeability chemistry metabolism osmosis pH protein multimerization transport at the cellular level Xenopus laevis Animals Aquaporins Biological Transport Cell Membrane Cell Membrane Permeability Hydrogen-Ion Concentration Osmosis Plant Proteins Protein Multimerization Protons Water Xenopus laevis Sigaut, Lorena Soto, Gabriela Cynthia Ayub, Nicolás Daniel PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry
topic_facet	aquaporin plant protein proton water animal cell membrane cell membrane permeability chemistry metabolism osmosis pH protein multimerization transport at the cellular level Xenopus laevis Animals Aquaporins Biological Transport Cell Membrane Cell Membrane Permeability Hydrogen-Ion Concentration Osmosis Plant Proteins Protein Multimerization Protons Water Xenopus laevis
description	Many plasma membrane channels form oligomeric assemblies, and heterooligomerization has been described as a distinctive feature of some protein families. In the particular case of plant plasma membrane aquaporins (PIPs), PIP1 and PIP2 monomers interact to form heterotetramers. However, the biological properties of the different heterotetrameric configurations formed by PIP1 and PIP2 subunits have not been addressed yet. Upon coexpression of tandem PIP2-PIP1 dimers in Xenopus oocytes, we can address, for the first time to our knowledge, the functional properties of single heterotetrameric species having 2:2 stoichiometry. We have also coexpressed PIP2-PIP1 dimers with PIP1 and PIP2 monomers to experimentally investigate the localization and biological activity of each tetrameric assembly. Our results show that PIP2-PIP1 heterotetramers can assemble with 3:1, 1:3, or 2:2 stoichiometry, depending on PIP1 and PIP2 relative expression in the cell. All PIP2-PIP1 heterotetrameric species localize at the plasma membrane and present the same water transport capacity. Furthermore, the contribution of any heterotetrameric assembly to the total water transport through the plasma membrane doubles the contribution of PIP2 homotetramers. Our results also indicate that plasma membrane water transport can be modulated by the coexistence of different tetrameric species and by intracellular pH. Moreover, all the tetrameric species present similar cooperativity behavior for proton sensing. These findings throw light on the functional properties of PIP tetramers, showing that they have flexible stoichiometry dependent on the quantity of PIP1 and PIP2 molecules available. This represents, to our knowledge, a novel regulatory mechanism to adjust water transport across the plasma membrane. © 2016 Biophysical Society.
author	Sigaut, Lorena Soto, Gabriela Cynthia Ayub, Nicolás Daniel
author_facet	Sigaut, Lorena Soto, Gabriela Cynthia Ayub, Nicolás Daniel
author_sort	Sigaut, Lorena
title	PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry
title_short	PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry
title_full	PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry
title_fullStr	PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry
title_full_unstemmed	PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry
title_sort	pip water transport and its ph dependence are regulated by tetramer stoichiometry
publishDate	2016
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00063495_v110_n6_p1312_Jozefkowicz http://hdl.handle.net/20.500.12110/paper_00063495_v110_n6_p1312_Jozefkowicz
work_keys_str_mv	AT sigautlorena pipwatertransportanditsphdependenceareregulatedbytetramerstoichiometry AT sotogabrielacynthia pipwatertransportanditsphdependenceareregulatedbytetramerstoichiometry AT ayubnicolasdaniel pipwatertransportanditsphdependenceareregulatedbytetramerstoichiometry
_version_	1768545814094807040

PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry

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