title: Pyruvate kinase is a dosage-dependent regulator of cellular amino acid homeostasis.
abstract: The glycolytic enzyme pyruvate kinase (PK) is required for cancer development, and has been implicated in the metabolic transition from oxidative to fermentative metabolism, the Warburg effect. However, the global metabolic response that follows changes in PK activity is not yet fully understood. Using shotgun proteomics, we identified 31 yeast proteins that were regulated in a PK-dependent manner. Selective reaction monitoring confirmed that their expression was dependent on PK isoform, level and activity. Most of the PK targets were amino acid metabolizing enzymes or factors of protein translation, indicating that PK plays a global regulatory role in biosynthethic amino acid metabolism. Indeed, we found strongly altered amino acid profiles when PK levels were changed. Low PK levels increased the cellular glutamine and glutamate concentrations, but decreased the levels of seven amino acids including serine and histidine. To test for evolutionary conservation of this PK function, we quantified orthologues of the identified PK targets in thyroid follicular adenoma, a tumor characterized by high PK levels and low respiratory activity. Aminopeptidase AAP-1 and serine hydroxymethyltransferase SHMT1 both showed PKM2- concentration dependence, and were upregulated in the tumor. Thus, PK expression levels and activity were important for maintaining cellular amino acid homeostasis. Mediating between energy production, ROS clearance and amino acid biosynthesis, PK thus plays a central regulatory role in the metabolism of proliferating cells.
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: Katharina
authors.initials: K
authors.lastname: Bluemlein
authors.forename: Matthias
authors.initials: M
authors.lastname: Glückmann
authors.forename: Nana-Maria
authors.initials: NM
authors.lastname: Grüning
authors.forename: René
authors.initials: R
authors.lastname: Feichtinger
authors.forename: Antje
authors.initials: A
authors.lastname: Krüger
authors.forename: Mirjam
authors.initials: M
authors.lastname: Wamelink
authors.forename: Hans
authors.initials: H
authors.lastname: Lehrach
authors.forename: Stephen
authors.initials: S
authors.lastname: Tate
authors.forename: Daniel
authors.initials: D
authors.lastname: Neureiter
authors.forename: Barbara
authors.initials: B
authors.lastname: Kofler
authors.forename: Markus
authors.initials: M
authors.lastname: Ralser
mesh_terms: D000236:Adenoma / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D000596:Amino Acids / Q000378:metabolism*; D000626:Aminopeptidases / Q000378:metabolism; D048708:Cell Growth Processes / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic; D012696:Glycine Hydroxymethyltransferase / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D020543:Proteome / Q000378:metabolism; D011770:Pyruvate Kinase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D015854:Up-Regulation
chemical_list: D000596:Amino Acids; D007527:Isoenzymes; D020543:Proteome; D012696:Glycine Hydroxymethyltransferase; C520541:SHMT protein, human; D011770:Pyruvate Kinase; D000626:Aminopeptidases