INVESTIGADORES
AMODEO Gabriela
congresos y reuniones científicas
Título:
Loop B Serine phosphorylation status differentially affects pH sensing of PIP aquaporins
Autor/es:
AGUSTIN YANEFF; MARÍA CECILIA ALIAGA FANDIÑO; KARINA ALLEVA; LIA PIETRASANTA; GABRIELA AMODEO
Lugar:
Sierra de la Ventana
Reunión:
Congreso; XLIII Reunión Anual de la Sociedad Argentina de Biofísica; 2014
Institución organizadora:
Sociedad Argentina de Biofisica
Resumen:
The crystallization of SoPIP2;1 in an open and close conformation as well as biophysical evidences have allowed to propose a gating mechanism in PIP aquaporins. A close state seems to prevail under different stimuli: cytosolic pH decrease2, intracellular Ca2+ concentration increase and desphosphorylation of specific serines1. In previous work, we characterize FaPIP1;1 and FaPIP2;1 in terms of their Pf and pH inhibition response and demonstrate that heterotetramerization affects pH gating sensitivity2. In the light of these findings we decided to explore if phosphorylation of specific residues is involved in this response. Several PIP2 mutants where Serine from the loop B was replaced to alanine showed less activity as water channels when expressed in Xenopus laevis oocytes3?5 or yeast6,7. However, for several plant species, loop B serine has shown to be non-phosphorylated in vivo4,5,8. In this work, we generate loop B mutants (FaPIP2;1S121A and FaPIP1;1S131A) in order to simulate desphosphorylated state and characterize their behavior in terms of Pf and pH inhibition response. Our results show that loop B serine phosphorylation status affects pH gating sensitivity for FaPIP2;1 but not for FaPIP1;1. Thus, we propose a crosstalk between different regulatory mechanisms (heterotetramerization, serine phosphorylation status and pH sensitivity) that would rule the Pf of a membrane that express PIPs.