The N-terminal 236 residues of Ssa4p, a hsp70 in budding yeast, are sufficient to target GFP to nuclei in ethanol-treated cells; this transport is mediated by the karyopherin-beta Nmd5p. Ssa4p(1-236)-GFP nuclear accumulation upon ethanol exposure depends on the cell surface sensors Wsc1p and Mid2p as well as protein kinase C, an activator of the cell integrity MAPK cascade. I have analyzed the distribution of Ssa4p(1-236)-GFP and Nmd5p-His6-HA in deletion mutants of the cell integrity MAPK cascade and demonstrate that this pathway controls ethanol-induced nuclear accumulation of Ssa4p(1-236)-GFP. Protein phosphorylation regulates protein trafficking, and I have studied this modification for Ssa4p(1-236)-GFP, Nmd5p and the nucleoporin Nsp1p. My results suggest that the phosphorylation status of Nmd5p may change when cells are treated with ethanol, and threonine was identified as the putative target residue(s) for modification. Furthermore, Snf1p kinase is required for stress-induced nuclear accumulation of Ssa4p(1-236)-GFP; my data are in line with the idea that Snf1p kinase phosphorylates a threonine residue present at a consensus Snf1p site in Nmd5p. In summary, my studies link the stress-induced nuclear accumulation of Ssa4p(1-236)-GFP to the cell integrity MAPK pathway and Snf1p kinase.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.100748 |
| Date | January 2006 |
| Creators | Zhang, Rui, 1976- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Physiology.) |
| Rights | © Rui Zhang, 2006 |
| Relation | alephsysno: 002589169, proquestno: AAIMR32644, Theses scanned by UMI/ProQuest. |
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