A mathematical model approach dissects properties of interacting PIP aquaporins

AGUSTÍN YANEFF; LORENA SIGAUT; MERCEDES MARQUEZ; KARINA ALLEVA; LÍA ISABEL PIETRASANTA; GABRIELA AMODEO

Villa Carlos Paz

Congreso; XLII Reunión Anual SAB 2013; 2013

Sociedad Argentina de Biofísica

The plant aquaporin PIP subfamily represents one of the main gateways for water exchange at the level of the plasma membrane (PM). Among them, a fraction of this subfamily, known as PIP1, does not reach the PM unless they are co-expressed 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 modulate membrane water permeability (Pf) using a mathematical model approach applied to experimentally obtained Pf from different co-expression ratios of FaPIP1;1 and FaPIP2;1 or a FaPIP2;1 mutant. For the first time we dissect the individual contribution of each PIP, showing that i) PIP1 has also high water transport capacity when co-expressed with PIP2; ii) PIP2 water permeability is enhanced when it physically interacts with PIP1; iii) PIP1-PIP2 seem to form heterotetramers with a random stoichiometry arrangement. In this context, we propose FaPIP1;1 is a key participant in the regulation of the water movement across the membrane of cells expressing both aquaporins.