PIP aquoporin N and C terminals involved in the stability of the tetrameric assembly of the channel

SCOCHERA, F; GÓMEZ, N.; JOZEFKOWICZ, C.; AMODEO, G.; MOGLIONI, ALBERTINA; ALLEVA, K.; MARTINI, M. FLORENCIA

Sierra de la Ventana, Buenos Aires

Congreso; XLIII Reunión Anual Sociedad Argentina de Biofísica (SAB); 2014

Sociedad Argentina de Biofísica (SAB)

PIP is an aquaporin subfamily of tetrameric water channels formed by different paralogues, PIP1 and PIP2. PIP2 can get plasma membrane while PIP1 stay in the interior of the cell unless co-expressed with PIP2. Interestingly, when co-expressed, PIP1 and PIP2 form heterotetrameric assemblies and their intermolecular interaction regulates tetramer biological activity. PIP2 loop A is a key structural element to control heterotetramerization1. However, other structural elements involved in homotetramer, or even heterotetramer stabilization, are unknown. Here, we studied PIP´s quaternary structure stabilization through N and C inter-monomeric terminals. We assayed, by molecular dynamics simulations in an NPT ensemble, the interaction of these terminal peptides corresponding to PIP2 or PIP1 but also the hetero-interaction of PIP2 N-ter with PIP1 C-ter and viceversa. The interaction energies as the specific interactions show differences according to the type of PIP. Our preliminary results suggests that the energy interaction between PIP2 N and C inter-monomeric terminals is more stable than PIP1 one. This results shed light on N and C terminals as relevant elements in the stability of PIP ensemble.