title: Overcoming the metabolic burden of protein secretion in Schizosaccharomyces pombe--a quantitative approach using 13C-based metabolic flux analysis.
abstract: Protein secretion in yeast is generally associated with a burden to cellular metabolism. To investigate this metabolic burden in Schizosaccharomyces pombe, we constructed a set of strains secreting the model protein maltase in different amounts. We quantified the influence of protein secretion on the metabolism applying (13)C-based metabolic flux analysis in chemostat cultures. Analysis of the macromolecular biomass composition revealed an increase in cellular lipid content at elevated levels of protein secretion and we observed altered metabolic fluxes in the pentose phosphate pathway, the TCA cycle, and around the pyruvate node including mitochondrial NADPH supply. Supplementing acetate to glucose or glycerol minimal media was found to improve protein secretion, accompanied by an increased cellular lipid content and carbon flux through the TCA cycle as well as increased mitochondrial NADPH production. Thus, systematic metabolic analyses can assist in identifying factors limiting protein secretion and in deriving strategies to overcome these limitations.
authors.affiliation: Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Klein
authors.affiliation: Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Lange
authors.affiliation: PomBioTech GmbH, 66123 Saarbruecken, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Wilhelm
authors.affiliation: PomBioTech GmbH, 66123 Saarbruecken, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Bureik
authors.affiliation: Genomatica, Inc., 10520 Wateridge Circes, San Diego, CA 92121, USA.
authors.forename: Tae-Hoon
authors.initials: TH
authors.lastname: Yang
authors.affiliation: Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Heinzle
authors.affiliation: Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany. Electronic address: ko.schneider@mx.uni-saarland.de.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Schneider
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D007553:Isotope Labeling / Q000379:methods; D055442:Metabolome; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D000520:alpha-Glucosidases / Q000235:genetics / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D011994:Recombinant Proteins; D000520:alpha-Glucosidases
keywords: (13)C metabolic flux analysis; Macromolecular composition; Metabolic burden; Protein secretion; Schizosaccharomyces pombe; Substrate mixtures