Growth Arrest and DNA Damage inducible protein 45 alpha (Gadd45ɑ) is a protein well characterised for its role in DNA demethylation and cell cycle regulation. Behavioural studies showed that Gadd45ɑ-knock-out (KO) in mice impairs long-term memory consolidation following aversive learning tests. Proceeding experiments revealed that Gadd45ɑ is an RNA binding protein (RBP) that post-transcriptionally stabilises synaptic plasticity- and memory-related mRNAs in an activity-dependent manner. This project aims to decode the RNA and protein interaction networks of Gadd45ɑ in mouse hippocampal cells.Methods: Gadd45ɑ was cloned into an HA-APEX2-GFP (HAG) expression vector to generate the HA-APEX2-GFP-Gadd45ɑ (HAGG) fusion protein. HT22 cells were transfected with the HAGG or HAG expression vectors and later treated with biotin-phenol and hydrogen peroxide. Streptavidin immunoprecipitation was performed to isolate the biotin labelled proteins from the cell lysates. The eluted proteins were analysed by mass spectrometry and the enrichments of proteins in HAGG samples against HAG were calculated. Further analysis using the STRING database revealed protein-protein interaction networks and enrichment of GO term processes. Results: The HAGG/HAG analysis revealed 29 proteins enriched in the HAGG-expressing samples (Figure 1A). Analysis using the STRING database a 10-protein interaction network associated with [m]RNA processing and Gene expression (not shown). Conclusions: The results of the APEX2 proximity labelling method support the interaction of Gadd45ɑ with proteins involved in RNA and mRNA regulation in HT22 cells - a cell line derived from mouse hippocampal neurons - as well as its already characterised function in gene expression within the nucleus.