Elucidation of protein-protein interactions between human P53 tumor suppressor and the human aprataxin, SACM1L and METAP1 proteins

Aim: : The p53 transcription factor is involved in many biological functions such as cell cycle arrest, DNA repair, and apoptosis. P53 activity is regulated by many factors, including post translational modifications. In a preliminary study, 109 different yeast mutants without antioxidant genes were screened to find antioxidant genes that regulate human p53 activity in the heterologous yeast system. Within the scope of this screening, three of them (Δhnt3, Δsac1 and Δmap1) were found to have lower p53 activity compared to wild type cells. Human homologs of these genes (APTX, SACM1L and METAP1) are likely to play a role in the p53 regulation. The aim of this thesis is to determine the protein-protein interactions between p53 and human Aprataxin, SACM1L and METAP1 proteins. Material and Method: Yeast and human cell culture models were used to study protein protein interactions between p53 and target proteins. Yeast two hybrid system and Co-IP techniques were used to analyze protein-protein interactions. Results: In assays on yeast two hybrid, analyzes were made using the LacZ reporter gene to determine protein interactions. As a result of the analysis, it was observed that there was a significant difference in p53-APTX transformant between p53 containing transformants and control group transformants (p <0.05). In the subsequent Co-IP experiments, under normal growth conditions, direct interaction between p53 in MCF 10A cells and target genes was not detected as a result of Western Blot analysis. Conclusion: Our results suggest that only APTX interacts with p53 protein. However, this interaction was not be able to confirmed by the Co-IP experiments under normal growth conditions in MCF 10A cells. Key words: APTX, cancer, METAP1, p53, protein-protein interaction, SACM1L.