Regulation of Nuclear-cytoplasmic Translocation of RNA-Binding Protein HuR under Inflammation

Pundlik, Swarang Sachin (2017) Regulation of Nuclear-cytoplasmic Translocation of RNA-Binding Protein HuR under Inflammation. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Swarang Sachin Pundlik (12MS070)) MS_thesis,_Swarang_Sachin_Pundlik_(12MS070).pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

Resolution of inflammation is a critical phenomenon as failure in the resolution leads to chronic inflammatory condition, which causes several pathological conditions ranging from Heart disease to diabetes to cancer. Translation regulation mediated by miRNAs and RNA-binding proteins plays an important role during resolution of inflammation. HuR is one such RNA-binding protein. Recently, our lab has shown that HuR translocates into the cytoplasm upon inflammatory stimulus and rescues translation repression of pro-inflammatory tumor suppressor PDCD4. There are several reports of post translational modifications of HuR during inflammation. However, the mechanism and the role of post translational modifications behind the translocation is poorly understood. Here, we study the role of post translational modifications of HuR in its translocation from the nucleus into the cytoplasm upon inflammatory stimulus. With the help of EGFP tagged HuR, we have demonstrated the change in subcellular localization of wild type HuR upon inflammatory stimulus. By megaprimer based site directed mutagenesis approach, we constructed mutants of HuR and evaluated role of post translational modifications at arginine 217 and threonine 118 in translocation. We found that mutation at threonine 118 did not affect the cytoplasmic translocation upon inflammatory stimulus. However, mutation at arginine 217 was responsible for cytoplasmic localization of HuR in unstimulated cells. This suggests that arginine 217 is somehow involved in nuclear-cytoplasmic translocation of HuR.

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