DESCRIPTION OF THE INTERACTOME OF P8, A PROTEIN RELATED TO TUMOR PROGRESSION

VALACCO, P.; VARONE, C.; IOVANNA, JL; MORENO, S; BURLINGAME, A

Carlos Paz, Córdoba

Congreso; XLIV Reunion Anual de SAIB; 2008

Sociedad Argentina de Bioquimica y Biologia Molecular

p8 is an 8 kDa protein. It was identified due to its induction during the acute phase of pancreatitis. Functions related to stress, cell growth control and tumor progression have been proposed for p8. Analysis of its sequence identified a conserved region corresponding to a NLS. Immunocytochemistry experiments, show that p8’s sub-cellular localization depends on cell culture density, cell cycle and acetylation state of the cells. Its nuclear import is energy dependent; the NLS of p8 is necessary and sufficient to retain a heterologous protein in the nucleus. The fact that p8 is small enough to diffuse between nucleus and cytoplasm, but still possesses a NLS and a controlled localization suggests that it could associate to multiprotein complexes. Our aim is to identify these complexes. We generated a HEK 293 cell line that expresses p8 fused to HIS-FLAG tag. Tandem affinity purification was performed. The purified complexes were digested and analyzed by tandem mass spectrometry to identify proteins associated to p8. We generated a list of proteins that interact with p8. This, combined with two-hybrid experiments and bibliographical data, allowed to illustrate the p8 interactome, which shows proteins related to DNA repair and mRNA processing, suggesting that p8 is a multifunctional protein that interacts with different proteins in different cellular compartments.