This eukaryotic enzyme recognizes the sequence -Arg-Arg-X-Ser*/Thr*-Hpo, where * indicates the phosphorylated residue and Hpo indicates a hydrophobic residue.The inactive holoenzyme is a heterotetramer composed of two regulatory (R) subunits and two catalytic (C) subunits. Each R subunit occludes the active site of a C subunit and contains two binding sites for 3',5'-cyclic-AMP (cAMP). Binding of cAMP activates the enzyme by causing conformational changes that release two free monomeric C subunits from a dimer of the R subunits, i.e. R2C2 + 4 cAMP = R2(cAMP)4 + 2 C. Activity requires phosphorylation of a conserved Thr in the activation loop (T-loop) sequence (Thr198 in human Calpha; Thr224 in budding yeast Tpk2), installed by auto-phosphorylation or by the 3-phosphoinositide-dependent protein kinase-1 (PDPK1). Certain R2C2 combinations can be localized to particular subcellular regions by their association with diverse species of 'A Kinase-Anchoring Proteins' (AKAPs). The enzyme has been characterized from many organisms. Humans have three C units (Calpha, Cbeta, and Cgamma) encoded by the paralogous genes PRKACA, PRKACB and PRKACG, respectively, and four R subunits (R1alpha, RIbeta, RIIalpha and RIIbeta), encoded by PKRAR1A, PKRAR1B, PKRAR2A and PKRAR2B, respectively. Yeast (Saccharomyces cerevisiae) has three C subunits (Tpk1, Tpk2, and Tpk3) encoded by the paralogous genes TPK1, TPK2 and TPK3, respectively, and a single R subunit (Bcy1) encoded by the BCY1 gene. Some validated substrates of the enzyme include cAMP-response element-binding protein (CREB), phosphorylase kinase alpha subunit (PHKA), and tyrosine 3-monooxygenase (TH) in mammals; Adr1, Whi3, Nej1, and Pyk1 in yeast.
The taxonomic range for the selected organisms is: Saccharomyces cerevisiae The expected taxonomic range for this enzyme is: Eukaryota, Archaea, Bacteria
camp-dependent protein kinase, a kinase, cyclic amp-dependent protein kinase, camp-pka, camp/protein kinase a, capk, prkaca, camp dependent protein kinase, camp-dependent pka, cyclic amp-dependent protein kinase a, more
This eukaryotic enzyme recognizes the sequence -Arg-Arg-X-Ser*/Thr*-Hpo, where * indicates the phosphorylated residue and Hpo indicates a hydrophobic residue.The inactive holoenzyme is a heterotetramer composed of two regulatory (R) subunits and two catalytic (C) subunits. Each R subunit occludes the active site of a C subunit and contains two binding sites for 3',5'-cyclic-AMP (cAMP). Binding of cAMP activates the enzyme by causing conformational changes that release two free monomeric C subunits from a dimer of the R subunits, i.e. R2C2 + 4 cAMP = R2(cAMP)4 + 2 C. Activity requires phosphorylation of a conserved Thr in the activation loop (T-loop) sequence (Thr198 in human Calpha; Thr224 in budding yeast Tpk2), installed by auto-phosphorylation or by the 3-phosphoinositide-dependent protein kinase-1 (PDPK1). Certain R2C2 combinations can be localized to particular subcellular regions by their association with diverse species of 'A Kinase-Anchoring Proteins' (AKAPs). The enzyme has been characterized from many organisms. Humans have three C units (Calpha, Cbeta, and Cgamma) encoded by the paralogous genes PRKACA, PRKACB and PRKACG, respectively, and four R subunits (R1alpha, RIbeta, RIIalpha and RIIbeta), encoded by PKRAR1A, PKRAR1B, PKRAR2A and PKRAR2B, respectively. Yeast (Saccharomyces cerevisiae) has three C subunits (Tpk1, Tpk2, and Tpk3) encoded by the paralogous genes TPK1, TPK2 and TPK3, respectively, and a single R subunit (Bcy1) encoded by the BCY1 gene. Some validated substrates of the enzyme include cAMP-response element-binding protein (CREB), phosphorylase kinase alpha subunit (PHKA), and tyrosine 3-monooxygenase (TH) in mammals; Adr1, Whi3, Nej1, and Pyk1 in yeast.
GTPase activating proteins negatively regulate Ras in nutrient-poor conditions, downregulation of Ras lowers cAMP levels leading to reduced activity of protein kinase A
phosphorylation of Whi3 by PKA leads to its decreased interaction with CLN3 G1 cyclin mRNA and is required for the promotion of G1/S progression, phosphorylation state of Ser568 in Whi3 affects G1/S transition by modulating CLN2 transcription. PKA causes a decrease in cell size by downregulating Whi3 function. Implication of PKA-mediated modulation of Whi3 in multiple cellular events
i.e. Tpk1R324A, site-directed mutagenesis, a catalytically inactive PKA variant, that exhibits a stable binding to the substrate with increased affinity through a conformational change
Using substrate-binding variants of the cAMP-dependent protein kinase to identify novel targets and a kinase domain important for substrate interactions in Saccharomyces cerevisiae
Cyclic AMP-protein kinase A and Snf1 signaling mechanisms underlie the superior potency of sucrose for induction of filamentation in Saccharomyces cerevisiae
Mizunuma, M.; Tsubakiyama, R.; Ogawa, T.; Shitamukai, A.; Kobayashi, Y.; Inai, T.; Kume, K.; Hirata, D.
Ras/cAMP-dependent protein kinase (PKA) regulates multiple aspects of cellular events by phosphorylating the Whi3 cell cycle regulator in budding yeast