Transmitting the signal of excess nitrogen inSaccharomyces cerevisiaefrom the Tor proteins to the GATA factors: connecting the dots
Open Access
- 1 August 2002
- journal article
- review article
- Published by Oxford University Press (OUP) in FEMS Microbiology Reviews
- Vol. 26 (3), 223-238
- https://doi.org/10.1111/j.1574-6976.2002.tb00612.x
Abstract
Major advances have recently occurred in our understanding of GATA factor-mediated, nitrogen catabolite repression (NCR)-sensitive gene expression in Saccharomyces cerevisiae. Under nitrogen-rich conditions, the GATA family transcriptional activators, Gln3 and Gat1, form complexes with Ure2, and are localized to the cytoplasm, which decreases NCR-sensitive expression. Under nitrogen-limiting conditions, Gln3 and Gat1 are dephosphorylated, move from the cytoplasm to the nucleus, in wild-type but not rna1 and srp1 mutants, and increase expression of NCR-sensitive genes. ‘Induction’ of NCR-sensitive gene expression and dephosphorylation of Gln3 (and Ure2 in some laboratories) when cells are treated with rapamycin implicates the Tor1/2 signal transduction pathway in this regulation. Mks1 is posited to be a negative regulator of Ure2, positive regulator of retrograde gene expression and to be itself negatively regulated by Tap42. In addition to Tap42, phosphatases Sit4 and Pph3 are also argued by some to participate in the regulatory pathway. Although a treasure trove of information has recently become available, much remains unknown (and sometimes controversial) with respect to the precise biochemical functions and regulatory pathway connections of Tap42, Sit4, Pph3, Mks1 and Ure2, and how precisely Gln3 and Gat1 are prevented from entering the nucleus. The purpose of this review is to provide background information needed by students and investigators outside of the field to follow and evaluate the rapidly evolving literature in this exciting field.Keywords
This publication has 57 references indexed in Scilit:
- Gln3p Nuclear Localization and Interaction with Ure2p inSaccharomyces cerevisiaePublished by Elsevier BV ,2001
- A comprehensive two-hybrid analysis to explore the yeast protein interactomeProceedings of the National Academy of Sciences, 2001
- Phosphorylation Regulates the Interaction between Gln3p and the Nuclear Import Factor Srp1pPublished by Elsevier BV ,2001
- HEAT Repeats Mediate Plasma Membrane Localization of Tor2p in YeastJournal of Biological Chemistry, 2000
- Tripartite Regulation of Gln3p by TOR, Ure2p, and PhosphatasesJournal of Biological Chemistry, 2000
- Saccharomyces cerevisiae GATA Sequences Function as TATA Elements during Nitrogen Catabolite Repression and When Gln3p Is Excluded from the Nucleus by Overproduction of Ure2pJournal of Biological Chemistry, 2000
- Transport Between the Cell Nucleus and the CytoplasmAnnual Review of Cell and Developmental Biology, 1999
- NUCLEOCYTOPLASMIC TRANSPORT: The Soluble PhaseAnnual Review of Biochemistry, 1998
- Targets for Cell Cycle Arrest by the Immunosuppressant Rapamycin in YeastScience, 1991
- Yeast mutants pleiotropically impaired in the regulation of the two glutamate dehydrogenasesBiochemical and Biophysical Research Communications, 1973