| dc.contributor.author | Wang, Xiangmin. | en_US |
| dc.date.accessioned | 2014-10-21T12:36:41Z | |
| dc.date.available | 1997 | |
| dc.date.issued | 1997 | en_US |
| dc.identifier.other | AAINQ24786 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55528 | |
| dc.description | The yeast Gcs1 protein is a GTPase-activating protein for yeast Arf1 and Arf2, and it is involved in intracellular vesicular transport. Mutations in the GCS1 gene produce a novel growth defect. At a restrictive temperature, gcs1 mutant cells are specifically impaired for resumption of cell proliferation from stationary phase. In contrast, actively dividing gcs1 cells can maintain ongoing cell proliferation at the temperature that is restrictive for stationary-phase mutant cells. To further study the function of Gcs1 and the cellular processes taking place during the resumption of cell proliferation from stationary phase, I identified seven yeast genes which, when present in multiple copies, suppress the growth defect of gcs1 mutant cells. Of these seven genes, YCK1, YCK2, and YCK3 encode three different membrane-associated casein kinase I isoforms, CDC55 encodes a regulatory subunit of protein phosphatase 2A, YPT31 and YPT32 encode small GTP-binding proteins that belong to the YPT/Rab family of proteins, and IMH1 encodes a protein with extensive coiled-coil motifs. | en_US |
| dc.description | Membrane association of the casein kinase I enzymes is important for their ability to suppress the growth defect of gcs1 mutant cells, and a decrease in the Yck1 + Yck2 activity exacerbates that growth defect. These observations indicate that membrane-associated casein kinase I and Gcs 1 are involved in a common process. Similarly, a decrease in the Ypt31 + Ypt32 activity also exacerbates the growth defect of gcs1 mutant cells, suggesting that Ypt31 + Ypt32 and Gcs1 are also functionally related. Furthermore, increased casein kinase I activity suppresses the growth defect caused by insufficient Ypt31 + Ypt32 activity. Therefore, it is likely that increased activities of Ypt31 + Ypt32 and casein kinase I activate a parallel pathway that bypasses the need for Gcs1 during the resumption of cell proliferation from stationary phase. The non-essential Imh1 protein is structurally similar to Rabaptin-5, a direct effector of Rab5, and Imh1 has been reported as a low-copy suppressor of ypt6, suggesting that Imh1 might also be involved in vesicular transport. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1997. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Molecular. | en_US |
| dc.subject | Biology, Genetics. | en_US |
| dc.subject | Biology, Cell. | en_US |
| dc.title | Identification of yeast proteins that can compensate for loss of the Gcs1 ARF GAP. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
