title: Characterization of fungal RTG2 genes in retrograde signaling of Saccharomyces cerevisiae.
abstract: Changes in the functional status of mitochondria result in the transcriptional activation of a subset of nuclear-encoded genes in a process referred to as retrograde signaling. In Saccharomyces cerevisiae, this molecular link between mitochondria and the nuclear genome is controlled by three key signaling proteins: Rtg1p, Rtg2p, and Rtg3p. Although the retrograde signaling response has been well characterized in S. cerevisiae, very little is known about this pathway in other fungi. In this study, we selected four species having uncharacterized open reading frames (ORFs) with more than 66% amino acid identity to Rtg2p for further analysis. To determine whether these putative RTG2 ORFs encoded bona fide regulators of retrograde signaling, we tested their ability to complement the defects associated with the S. cerevisiae rtg2Δ mutant. Specifically, we tested for complementation of citrate synthase (CIT2) and aconitase (ACO1) at the transcript and protein levels, glutamate auxotrophy, and changes in the interaction between Rtg2p and the negative regulator Mks1p. Our findings show that all four Rtg2p homologs are functional upon activation of retrograde signaling, although their degree of complementation varied. In addition, all Rtg2p homologs showed a marked reduction in Mks1p binding, which may contribute to their altered responses to retrograde signaling.
authors.affiliation: Department of Biological Sciences, Mississippi State University, P.O. Box GY, Starkville, MS 39762, USA.
authors.forename: Ercan Selçuk
authors.initials: ES
authors.lastname: Ünlü
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Narayanan
authors.forename: Donna M
authors.initials: DM
authors.lastname: Gordon
mesh_terms: D000154:Aconitate Hydratase / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005800:Genes, Fungal; D018698:Glutamic Acid / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D016366:Open Reading Frames; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C079379:RTG2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D018698:Glutamic Acid; D002950:Citrate (si)-Synthase; D000154:Aconitate Hydratase
keywords: Mitochondria/nuclear signaling; citrate synthase; glutamate auxotrophy