Heteromerization of PIP aquaporins affects their intrinsic permeability

• Autores: Yaneff, A.; Sigaut, L.; Marquez, M.; Alleva, K.; Pietrasanta, L.I.; Amodeo, G.
• Año de publicación: 2014
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Proc. Natl. Acad. Sci. U. S. A. 2014;111(1):231-236
• Materia: aquaporin; membrane protein; plasma membrane intrinsic protein 1; plasma membrane intrinsic protein 2; unclassified drug; acidification; article; cell membrane; channel gating; mathematical model; membrane permeability; molecular dynamics; permeability; pH; priority journal; protein expression; protein function; protein interaction; protein transport; regulatory mechanism; strawberry; water flow; water permeability; Animals; Aquaporins; Bacterial Proteins; Cell Membrane; Cytosol; Fragaria; Gene Expression Regulation, Plant; Hydrogen-Ion Concentration; Lipid Bilayers; Luminescent Proteins; Microscopy, Confocal; Models, Theoretical; Mutagenesis, Site-Directed; Oocytes; Permeability; Plant Proteins; Protein Multimerization; RNA, Complementary; Water; Xenopus laevis
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

The plant aquaporin plasma membrane intrinsic proteins (PIP) subfamily represents one of the main gateways for water exchange at the plasma membrane (PM). A fraction of this subfamily, known as PIP1, does not reach the PM unless they are coexpressed with a PIP2 aquaporin. Although ubiquitous and abundantly expressed, the role and properties of PIP1 aquaporins have therefore remained masked. Here, we unravel how FaPIP1;1, a fruit-specific PIP1 aquaporin from Fragaria x ananassa, contributes to the modulation of membrane water permeability (Pf) and pH aquaporin regulation. Our approach was to combine an experimental and mathematical model design to test its activity without affecting its trafficking dynamics. We demonstrate that FaPIP1;1 has a high water channel activity when coexpressed as well as how PIP1-PIP2 affects gating sensitivity in terms of cytosolic acidification. PIP1-PIP2 random heterotetramerization not only allows FaPIP1;1 to arrive at the PMbut also produces an enhancement of FaPIP2;1 activity. In this context, we propose that FaPIP1;1 is a key participant in the regulation of water movement across the membranes of cells expressing both aquaporins.
Fil:Sigaut, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.