Publication details
eIF3a/Rpg1/Tif32 accumulates in granules in osmotically stressed cells of Saccharomyces cerevisiae
| Authors | |
|---|---|
| Year of publication | 2003 |
| Type | Article in Periodical |
| Magazine / Source | Molecular Biology of the Cell |
| MU Faculty or unit | |
| Citation | |
| Field | Genetics and molecular biology |
| Keywords | yeast; osmotic stress; eIF3a/Rpg1/Tif32; Saccharomyces cerevisiae |
| Description | EIF3a/Rpg1/Tif32p is the essential subunit of the translation initiation factor eIF3 core complex of Saccharomyces cerevisiae. Besides interactions within the eIF3 complex, Rpg1p physically interacts with the actin-associated protein Sla2/End4/Mop2 and partially co-localizes with microtubules in cells fixed for immunofluorescence. Roles for these cytoskeletal interactions are still unknown. To monitor distribution of Rpg1p in living cells we prepared a C-terminal Rpg1-EGFP fusion. We found that Rpg1-EGFP was uniformly distributed in the cytoplasm of exponentially growing cells. Nevertheless, in osmotically stressed cells, Rpg1-EGFP re-localized to fluorescent granules dominantly associated with the bud tip and the neck between the mother and daughter cells. Disruption of microtubules and actin microfilaments, or the absence of Sla2p did not significantly affect formation, number or distribution of Rpg1-EGFP stress granules. In immunofluorescence, the cells treated with 1M NaCl for 60 minutes displayed Rpg1p granules and depolymerized microtubules. Distribution of the protein Elo3, a marker for endoplasmic reticulum, was not changed. The accumulation of Rpg1p in granules of stressed cells was confirmed by electron microscopy using immunogold labeling. We suggest that Rpg1/Tif32p mediates formation of stress granules. This work was financed by grant GACR 204/02/1424 to JH and Institutional Research Concept No. AV0Z5020903. |