title: Protein kinase A type I activates a CRE-element more efficiently than protein kinase A type II regardless of C subunit isoform.
abstract: BACKGROUND
  Protein kinase A type I (PKAI) and PKAII are expressed in most of the eukaryotic cells examined. PKA is a major receptor for cAMP and specificity is achieved partly through tissue-dependent expression and subcellular localization of subunits with different biochemical properties. In addition posttranslational modifications help fine tune PKA activity, distribution and interaction in the cell. In spite of this the functional significance of two forms of PKA in one cell has not been fully determined. Here we have tested the ability of PKAI and PKAII formed by expression of the regulatory (R) subunits RIα or RIIα in conjunction with Cα1 or Cβ2 to activate a co-transfected luciferace reporter gene, controlled by the cyclic AMP responsive element-binding protein (CREB) in vivo.
  
  
  RESULTS
  We show that PKAI when expressed at equal levels as PKAII was significantly (p < 0.01) more efficient in inducing Cre-luciferace activity at saturating concentrations of cAMP. This result was obtained regardless of catalytic subunit identity.
  
  
  CONCLUSIONS
  We suggest that differential effects of PKAI and PKAII in inducing Cre-luciferace activity depend on R and not C subunit identity.
authors.affiliation: Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Sognsvannsveien 9, P,O, Box 1046 Blindern, N- 0316 OSLO, Norway.
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Stakkestad
authors.forename: Anja C V
authors.initials: AC
authors.lastname: Larsen
authors.forename: Anne-Katrine
authors.initials: AK
authors.lastname: Kvissel
authors.forename: Sissel
authors.initials: S
authors.lastname: Eikvar
authors.forename: Sigurd
authors.initials: S
authors.lastname: Ørstavik
authors.forename: Bjørn S
authors.initials: BS
authors.lastname: Skålhegg
mesh_terms: D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D054743:Cyclic AMP-Dependent Protein Kinase Type I / Q000235:genetics / Q000378:metabolism*; D054746:Cyclic AMP-Dependent Protein Kinase Type II / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D057809:HEK293 Cells; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D020218:Response Elements
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D020033:Protein Isoforms; D000242:Cyclic AMP; D008156:Luciferases; D054743:Cyclic AMP-Dependent Protein Kinase Type I; D054746:Cyclic AMP-Dependent Protein Kinase Type II