Genetic interaction network of the Saccharomyces cerevisiae type 1 phosphatase Glc7

Abstract

BackgroundProtein kinases and phosphatases regulate protein phosphorylation, a critical means of modulating protein function, stability and localization. The identification of functional networks for protein phosphatases has been slow due to their redundant nature and the lack of large-scale analyses. We hypothesized that a genome-scale analysis of genetic interactions using the Synthetic Genetic Array could reveal protein phosphatase functional networks. We apply this approach to the conserved type 1 protein phosphatase Glc7, which regulates numerous cellular processes in budding yeast.ResultsWe created a novel glc7 catalytic mutant (glc7-E101Q). Phenotypic analysis indicates that this novel allele exhibits slow growth and defects in glucose metabolism but normal cell cycle progression and chromosome segregation. This suggests that glc7-E101Q is a hypomorphic glc7 mutant. Synthetic Genetic Array analysis of glc7-E101Q revealed a broad network of 245 synthetic sick/lethal interactions reflecting that many processes are required when Glc7 function is compromised such as histone modification, chromosome segregation and cytokinesis, nutrient sensing and DNA damage. In addition, mitochondrial activity and inheritance and lipid metabolism were identified as new processes involved in buffering Glc7 function. An interaction network among 95 genes genetically interacting with GLC7 was constructed by integration of genetic and physical interaction data. The obtained network has a modular architecture, and the interconnection among the modules reflects the cooperation of the processes buffering Glc7 function.ConclusionWe found 245 genes required for the normal growth of the glc7-E101Q mutant. Functional grouping of these genes and analysis of their physical and genetic interaction patterns bring new information on Glc7-regulated processes.

A New Fluorescence-Based Method Identifies Protein Phosphatases Regulating Lipid Droplet Metabolism

“…gac1 and bni4 were identified as hlc while reg1 as llc . Glc7p phosphatase interacts with different subunits each leading Glc7p to different substrates regulating several cellular processes as cell cycle, glycogen, sugar and lipid metabolism [60] , [61] . Gac1p and Bni4p recruit Glc7p phosphatase to glycogen synthase Gsy2p [62] or the bud neck [63] , respectively, and normally they may sequester some Glc7 phosphatase away from Snf1p.…”

Mitosis-Specific Regulation of Nuclear Transport by the Spindle Assembly Checkpoint Protein Mad1p

“…mitotic progression. We targeted the protein phosphatase Glc7p based on several observations: (1) genetic analysis has uncovered a functional interaction between Glc7p and Nup53p (Logan et al, 2008), a key component of the KTIP machinery; (2) Glc7p contains a putative Kap121p NLS and is concentrated in the nucleus of asynchronous cells; (3) Glc7p is an antagonist of Ipl1p function (reviewed in Lesage et al, 2011); and (4) mutations that reduce nuclear levels of Glc7p rescue growth of ipl1 ts mutants (Bharucha et al, 2008;Pinsky et al, 2006b;Tatchell et al, 2011). Using Glc7-GFP and cells containing the kap121-34 temperature-sensitive allele, we showed that nuclear accumulation of Glc7p was dependent on Kap121p ( Figure S6).…”

Replication stress-induced Exo1 phosphorylation is mediated by Rad53/Pph3 and Exo1 nuclear localization is controlled by 14-3-3 proteins

“…The established lack of viability of glc7 -null cells [38] prompted us to take advantage of a catalytic mutant of the phosphatase ( glc7 - E101Q ), which displays defects in glucose metabolism but normal cell cycle progression and chromosome segregation [39]. The data showed that the pattern of Exo1 or Rad53 mobility during recovery from HU in the glc7 - E101Q background was not altered in comparison to control cells (Fig.…”