Poster abstracts
Poster number 109 submitted by Paige Nati
Investigating the dynamic regulation of arginine methylation on the SR-/hnRNP-like protein Npl3
Paige Nati (Department of Biological Sciences, University at Buffalo), Joe Ricottone (Department of Biological Sciences, University at Buffalo), Tao Liu (Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center), Michael C. Yu (Department of Biological Sciences, University at Buffalo)
Abstract:
Npl3 is an RNA-binding protein in Saccharomyces cerevisiae involved in various cellular processes, such as translation, pre-mRNA splicing, and mRNA export. Npl3 undergoes arginine methylation by the protein arginine methyltransferase Hmt1 which facilitates its cellular localization and protein-protein interactions. Whether dynamic regulation of arginine methylation occurs in budding yeast remains an outstanding question. In mammalian cells, no bona fide arginine demethylase has been identified. Instead, a different class of enzyme, peptidyl arginine deiminases (PADs), can counteract the action of arginine methylation by converting a monomethylarginine to citrulline. Notably, no homolog of PAD has been identified in the budding yeast. We have recently observed changes in the level of Npl3 methylation across different growth stages, suggesting the presence of a putative mechanism that regulates Npl3 methylation. Specifically, we observed an increase in the ratio of methylated to total Npl3 in the fermentative growth phase of yeast, followed by a decrease in this ratio in the respiratory growth phase. Based on these observations, we hypothesize that a proteostasis mechanism exists that selectively degrades methyl-Npl3, thereby maintaining a specific ratio of methylated to non-methylated Npl3. Here, we will present our latest data on the selective degradation of methyl-Npl3 by investigating the two main degradation pathways: the ubiquitin-proteasome system and autophagy.
Keywords: Arginine methylation, proteostasis