Download or read book The RAS PKA Signaling Pathway in Saccharomyces Cerevisiae May Regulate the Function of Proteins Associated with the RPB1P CTD to Coordinate Transcription with Nutrient Availability written by Susie C. Howard and published by . This book was released on 2002 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2002 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enzyme Catalyzed Electron and Radical Transfer written by Andreas Holzenburg and published by Springer Science & Business Media. This book was released on 2000-12-31 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dramatic advances have been made in recent years in the field of redox enzymology which has resulted in an increase of research activities. This volume will cover the recent milestone developments in this field by leading experts, uniting theory and experiment, and selecting contributions to illustrate important aspects of the mechanisms of electron and radical transfer in proteins. Features: A demonstration of the key principles controlling biological redox reactions; Experimental studies of `simple' soluble systems in various enzyme familiies to illustrate concepts in the control of electron transfer reactions; Detail of advances made in membrane electron transfer through structural descriptions of key membrane-embedded proteins; Appeal to those interested in the design and use of redox enzymes, from academics to industrialists.
Download or read book The Ras PKA Pathway Controls Transcription of Genes Involved in Stationary Phase Entry in Saccharomyces Cerevisiae written by Ya-Wen Chang and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Upon nutrient deprivation, Saccharomyces cerevisiae cells arrest division and enter into a specialized resting state, known as stationary phase. The entry into this resting state is regulated, in part, by the Ras/PKA (cAMP-dependent protein kinase) signaling pathway. We are interested in understanding the mechanisms regulating stationary phase biology in S. cerevisiae, with an ultimate goal of defining the targets of PKA that are responsible for this growth control. To this end, we have identified a collection of mutants that exhibited a defective transcriptional response to nutrient limitation and failed to enter into a normal stationary phase. These rye mutants were isolated on the basis of defects in the regulation of YGP1 expression. We found that the levels of YGP1 were significantly elevated in the rye mutants during the log phase of growth. The rye defects were not specific to this YGP1 expression defect because these mutants also exhibited multiple defects in stationary phase properties, including an inability to survive periods of prolonged starvation and a failure to tolerate a mild heat shock. These data indicated that the RYE genes may encode important regulators of yeast cell growth. Interestingly, three of these RYE genes encoded the Srb proteins, Srb9p, Srb10p, and Srb11p. These Srb proteins are components of the Srb complex associated with the RNA polymerase II holoenzyme. We found that specific transcription defects associated with these srb mutations were suppressed by RAS2val19, a hyperactive allele of RAS2. However, increased Ras signaling was not able to correct the expression defects associated with an srb9 null mutant, suggesting that the Srb9 protein is essential for the Ras suppression. Moreover, there are two potential PKA consensus sites in Srb9p. Our results showed that the suppression of the srb9 defects required the presence of these two PKA sites. In addition, we have found that Srb9p was phosphorylated by PKA in vitro and in vivo. In all, our results suggest that Srb9p is a substrate for PKA, and that this phosphorylation of Srb9p modulates the in vivo activity of the Srb complex to regulate transcription of a subset of genes involved in stationary phase entry.
Download or read book The Ras PKA Signaling Pathway Regulates Growth in Response to Nutrient Availability in S Cerevisiae Coordinately with the Ror Pathway written by Vidhya Ramachandran and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In addition to post-translational regulation, cells respond to changing nutrient levels by modulating mRNA turnover in the cell, to regulate gene expression as well as translation. In the recent years, the mRNP aggregates known as P-bodies have emerged as a major site and player in mRNA decapping and decay. Very little is known about the regulation of P-body formation in response to nutrient deprivation. To this end, our study in Chapter 3 describes a novel aspect of P-body biology, wherein PKA targets the P-body component Pat1, in response to nutrient deprivation, to regulate P-body formation in S. cerevisiae. Thus, Ras/PKA signaling might constitute a link between nutrient levels and mRNA turnover facilitated by P-bodies.
Download or read book An Evolutionary Proteomics Approach for the Identification of PKA Targets in Saccharomyces Cerevisiae Identifies Atg1 and Atg13 Two Proteins that Play a Central Role in the Regulation of Autophagy by the Ras PKA Pathway and the Tor Pathway written by Joseph Stephan and published by . This book was released on 2008 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A cell in its natural environment spends its time in a quiescent state known as G0 . A challenge the cell faces is to determine when the conditions are favorable for it to grow. The cell accomplishes this task through the combined actions of signaling pathways. These pathways link cells to the extracellular environment and act as molecular switches that engage the cell into a growth program when the conditions are favorable. In the budding yeast Saccharomyces cerevisiae, two signaling pathways that regulate growth in response to the availability of nutrients are the Tor kinase pathway and the Ras/cAMP dependent protein kinase (PKA) pathway. In Chapter 2, we describe an evolutionary proteomics approach for the identification of PKA targets in S. Cerevisiae. In this method, we use a PKA target consensus site and mine the yeast proteome for occurrences of this consensus. Next, we ask if these sites have been conserved through evolution in related yeast species. We found that conservation of a PKA site correlated with the likelihood of that site being recognized by PKA. This approach identified 44 substrates of PKA in yeast. One subset of targets, the AuTophaGy-related proteins Atg1, Atg13 and Atg18, was involved in the process of autophagy. Autophagy has been implicated in a number of cellular processes including aging and cancer. In yeast, this process is fully induced following nutrient limitation and allows the cell to survive prolonged periods of starvation. Previous work in yeast has shown that both the Tor and the Ras/pathways negatively regulate autophagy during the normal phase of growth. We focus on one particular PKA target, Atg1, and show that Atg1 is regulated by PKA. In chapter 3, we extend our analysis to Atg13. We find that this protein is a critical target of the Ras/PKA pathway. Atg13 is also regulated by the Tor pathway, and our data suggest that it might be a nexus of signal integration within the autophagy machinery. Tor and PKA appear to respond to different nutritional cues to provide separate inputs in the regulation of Atg13, thus regulating different aspects of the autophagy process.
