| dc.description.abstract | Sub-cellular localization is key to the specific function of proteins. Proteins can be recruited to different cell compartments via their interaction with the signaling lipids, polyphosphoinositides (PPIn). While their actions have been comprehensively documented in cytoplasmic membranes, these lipids are also present in membrane-less compartments within the nucleus. To understand the function of PPIn in the nucleus, we thought to identify nuclear PPIn binding proteins using quantitative mass spectrometry combined with PPIn affinity pull down. Using this approach, we identified ErbB3-binding protein 1 (EBP1), known to contribute to many cellular functions through interactions with RNA, DNA as well as other proteins. Using biochemical and biophysical approaches, we have demonstrated a direct interaction between EBP1 and PPIns via two lysine rich motifs located in the N- and C-termini. The C-terminal motif was shown to be required for the localization of EBP1 in nucleoli. A frameshift tumor mutant which introduced additional basic residues in the C-terminal motif led to an increase in PPIn binding and nucleolar localization of EBP1. Here we showed that the nucleolar presence of EBP1 correlated with the presence of rRNA for the WT and the frameshift tumor mutant but not the C-term PPIn-binding mutant. This suggests a molecular link between EBP1’s localization and its subsequent effect on nucleolar processes thereby playing a role in cells transformation. We also performed CRISPR/CAS genome editing of exon 2 on PA2G4 gene in HEK293T cells however it didn’t yield any fruitful outcomes. The clones analyzed by sequencing were wild type with no expected change, though few clones showed reduction at protein level with one clone suggesting an in-frame deletion | en_US |
