Amino acids regulate the transcription, internal sorting, and intrinsic activity of the general amino acid permease (GAP1) in S. cerevisiae

The high capacity general amino acid permease in Saccharomyces cerevisiae (GAP1) is regulated such that it actively imports amino acids into the cell from the extracellular medium only when internal amino acid levels are low. Regulation of activity allows the cell to rapidly and reversibly modulate amino acid import according to the nitrogen requirements of the cell. I have explored three distinct modes of action by which amino acids repress GAP1 activity: transcriptionally, by regulation of ubiquitin-mediated intracellular sorting, and by transport-dependent inactivation at the plasma membrane. Transcriptional regulation of GAP1 by two nutrient responsive GATA transcription factors, Nillp and Gln3p, allows the cell to modulate expression of the permease in response to both amino acid quantity and nitrogen source quality. Any Gaplp that is expressed in the presence of elevated internal amino acids is sorted to the vacuole and degraded or stored in internal compartments from which the permease can be rapidly mobilized to the plasma membrane when amino acid levels become limiting.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Biology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Risinger, April L. (April Lynn)

Advisor dc:contributor.advisor

• Chris A. Kaiser.

• Biology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/38991

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/38991