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Ras1 Phosphorylation and its Role in Nutrient Signaling
Author(s) -
Sethupathi Sheetal Kasi,
Jin Xin,
Wang Yuqi
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.lb92
Subject(s) - phosphorylation , serine , chemistry , phosphorylation cascade , alanine , microbiology and biotechnology , residue (chemistry) , protein phosphorylation , biochemistry , biology , protein kinase a , amino acid
Ras1 is a small GTPase found in Saccharomyces cerevisiae that regulates nutrient signaling and is known to undergo phosphorylation. Studies were conducted to gain a better understanding of the functional consequences and the regulation of Ras1 phosphorylation. Site‐directed mutagenesis was used to mutate critical serine residues to alanine residues. A serine residue at the C‐terminal region of Ras1 was identified as an important residue for Ras1 phosphorylation as mutating this serine residue to alanine drastically diminished the level of Ras1 phosphorylation. Additionally, phosphorylated Ras1 accumulates as cells approach the stationary phase of growth. Similarly, cells exposed to nitrogen starvation exhibit increased levels of phosphorylated Ras1. By blocking the phosphorylation of Ras1, we find that the level of autophagy decreases. Together, these findings reveal phosphorylation of Ras1 as a mechanism in regulating cellular responses to nitrogen starvation.