title: Expression of RCK2 MAPKAP (MAPK-activated protein kinase) rescues yeast cells sensitivity to osmotic stress.
abstract: BACKGROUND
  Saccharomyces cerevisiae is the micro-organism of choice for the conversion of fermentable sugars during beverage or bioethanol fermentations. These fermentations are characterised by high osmotic stress on a yeast cell, with selected brewing fermentations beginning at 20-25% fermentable sugars and bioethanol fermentations at 13% fermentable sugars.
  
  
  RESULTS
  RCK2 encodes for a MAPKAP (MAPK-activated protein kinase) enzyme and was identified on a locus by QTL analysis in yeast cells under osmotic stress, RCK2 expression was placed under a tetracycline regulatable vector and rescued glucose, sorbitol or glycerol induced osmotic stress in an rck2 null strain. A strain overexpressing RCK2 had significantly faster fermentation rates when compared with the empty vector control strain.
  
  
  CONCLUSIONS
  Presence of RCK2 increased rates of glucose utilisation (~40 g glucose in first 8 h) during a 15% glucose fermentation and concurrent production of ethanol when compared with empty vector controls. Tolerance to osmotic stress using the tetracycline regulatable vectors could be turned off with the addition of tetracycline returning a rck2 null strain back to osmotic sensitivity.
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Nottingham, LE12 5RD, UK. vinod.kumar@nottingham.ac.uk.
authors.forename: V
authors.initials: V
authors.lastname: Kumar
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Nottingham, LE12 5RD, UK. andrew.hart@nottingham.ac.uk.
authors.forename: A J
authors.initials: AJ
authors.lastname: Hart
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Nottingham, LE12 5RD, UK. tithira.wimalasena@gmail.com.|Kingston Research Ltd, SaltEnd Chemicals Park, Hull, UK. tithira.wimalasena@gmail.com.
authors.forename: T T
authors.initials: TT
authors.lastname: Wimalasena
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Nottingham, LE12 5RD, UK. gregory.tucker@nottingham.ac.uk.
authors.forename: G A
authors.initials: GA
authors.lastname: Tucker
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Nottingham, LE12 5RD, UK. darren.greetham@nottingham.ac.uk.
authors.forename: D
authors.initials: D
authors.lastname: Greetham
mesh_terms: D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D009997:Osmotic Pressure; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; C407464:RCK2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D005947:Glucose