CHARACTERIZATION OF THE ALTERNATIVE SPLICING VARIANT OF THE PIP SUBFAMILY IN Medicago Truncatula: THE TRUNCATED PROTEINS VARIANTS AS NEW ELEMENTS OF HETERO-OLIGOMERIZATION REGULATION

VICTORIA ANDREA VITALI; CINTIA JOZEFKOWICZ; ROMINA FRARE; EZEQUIEL PETRILLO; GERD PATRICK BIENERT; GABRIELA SOTO; KARINA ALLEVA

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

PIPs are transmembrane proteins of great biological importancegiven the large number of representatives found in plants and thespecific ability to transport different small compounds (water, CO2, H2O2, ions). The functional diversity and localization of this proteinfamily is usually attributed to three possible mechanisms: a) transcriptional regulation and mRNA processing; B) interaction of different monomers forming hetero-oligomers and c) the presence ofregulatory subunits coupled to the structure of the transmembraneproteins. To date, in this family, important advances have been madein understanding the post-translational regulation mechanisms suchas hetero-oligomerization and gating by pH, calcium, and / or phosphorylation. In contrast, the mechanisms of transcriptional regulation and RNA processing have not yet been addressed in depth.In the field of biology, co-transcriptional modifications occurring onmRNAs by splicing and alternative splicing are crucial in the proteindiversity present in eukaryotic organisms. Our preliminary results inMedicago truncatula suggest that splicing variants would determinethe translation of truncated protein variants. Unlike prior reports forother plant Membrane Intrinsic Proteins (MIPs), these protein variants lack two transmembrane helix and one extracellular loop. Theexistence of these variants open new questions about the role theycould play in PIP regulation in particular but in plant metabolism ingeneral