TPK1/YJL164C Summary Help

Standard Name TPK1 1
Systematic Name YJL164C
Alias PKA1 , SRA3 2
Feature Type ORF, Verified
Description cAMP-dependent protein kinase catalytic subunit; promotes vegetative growth in response to nutrients via the Ras-cAMP signaling pathway; inhibited by regulatory subunit Bcy1p in the absence of cAMP; phosphorylates and inhibits Whi3p to promote G1/S phase passage; partially redundant with Tpk2p and Tpk3p; phosphorylates pre-Tom40p, which impairs its import into mitochondria under non-respiratory conditions; TPK1 has a paralog, TPK3, that arose from the whole genome duplication (3, 4, 5, 6, 7, 8 and see Summary Paragraph)
Name Description Takashi's Protein Kinase 9
Chromosomal Location
ChrX:111159 to 109966 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gbrowse
Genetic position: -106 cM
Gene Ontology Annotations All TPK1 GO evidence and references
  View Computational GO annotations for TPK1
Molecular Function
Manually curated
High-throughput
Biological Process
Manually curated
High-throughput
Cellular Component
Manually curated
Regulators 6 genes
Resources
Classical genetics
null
overexpression
Large-scale survey
null
overexpression
Resources
505 total interaction(s) for 377 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 30
  • Affinity Capture-RNA: 1
  • Affinity Capture-Western: 12
  • Biochemical Activity: 290
  • PCA: 7
  • Reconstituted Complex: 12
  • Two-hybrid: 10

Genetic Interactions
  • Dosage Growth Defect: 6
  • Dosage Lethality: 2
  • Dosage Rescue: 24
  • Negative Genetic: 64
  • Phenotypic Enhancement: 6
  • Phenotypic Suppression: 8
  • Positive Genetic: 7
  • Synthetic Growth Defect: 9
  • Synthetic Lethality: 7
  • Synthetic Rescue: 10

Resources
Expression Summary
histogram
Resources
Length (a.a.) 397
Molecular Weight (Da) 46,076
Isoelectric Point (pI) 5.14
Localization
Phosphorylation PhosphoGRID | PhosphoPep Database
Structure
Homologs
sequence information
ChrX:111159 to 109966 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
SGD ORF map
Genetic position: -106 cM
Last Update Coordinates: 2011-02-03 | Sequence: 2011-02-03
Subfeature details
Relative
Coordinates
Chromosomal
Coordinates
Most Recent Updates
Coordinates Sequence
CDS 1..1194 111159..109966 2011-02-03 2011-02-03
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
Resources
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000003700
SUMMARY PARAGRAPH for TPK1

TPK1, TPK2, and TPK3 encode isoforms of the catalytic subunit of cAMP-dependent protein kinase (PKA), the effector kinase of the Ras-cAMP signaling pathway (reviews of the Ras-cAMP pathway can be found in 10 and 11). Through phosphorylation of various targets, PKA activity regulates processes involved in cell growth and response to nutrients and stress, such as nutrient sensing, energy metabolism, carbohydrate utilzation, cell cycle progression, thermotolerance, osmotic shock tolerance, sporulation, bud site selection, pseudohyphal growth, aging, and autophagy (reviewed in 11, 12, 13, and 14). PKA substrates include transcription factors (e.g., Rap1p (15), Hsf1p (16), Adr1p (17), Msn2p / Msn4p (18, 19), Ssn2p (20)), metabolic enzymes (e.g., Cho1p (21), Pfk2p (22), Nth1p (23)), and other regulatory kinases (e.g., Rim15p (24), Atg1p (25)). The PKA target site is R-[KR]-x-S, where S is the site of substrate phosphorylation (26, 27). PKA is conserved from yeast to man and TPK homologs have been identified in fission yeast, flies, worms, mice, pigs, cows, and humans (28, and reviewed in 29).

In the absence of cAMP, the catalytic subunits (Tpk1p, 2p, or 3p) form an inactive heterotetrameric complex with the PKA regulatory subunit Bcy1p, with two catalytic subunits bound to two regulatory subunits. In the presence of cAMP, Bcy1p binds to cAMP and dissociates from the complex as a homodimer, releasing the two catalytic subunits as active monomers (3 and references therein). PKA is also regulated through a cAMP feedback inhibition loop: PKA activity leads to a reduction in cAMP levels by directly phosphorylating enzymes which regulate cAMP production, (e.g. the GTPase Ras2p and the cAMP phosphodiesterase Pde1p), and the resulting decrease in cAMP levels promotes formation of the inactive heterotetrameric complex (30, 31, 32, 33). All three Tpk isozymes are phosphorylated and the phosphorylation state of Tpk1p has been shown to affect its substrate specificity constant and to be correlated with the availability of a fermentable carbon source (34).

The three PKA catalytic subunits are highly similar only in their C-terminal regions. Although the C-terminal 320 amino acids of Tpk1p and Tpk2p share 77% identity and are 88% and 75% identical to Tpk3p respectively, the N-terminal regions of these proteins share no sequence similarity and are heterogeneous in length (3). While no single TPK gene is essential, the presence of at least one of the isomers is required for normal growth (3). Mutations affecting levels of PKA activity lead to pleiotropic phenotypes because of the wide range of PKA substrates and their involvement in many cellular processes. Phenotypes due to hyperactive PKA signaling include rapamycin resistance, accelerated pseudohyphal growth, transient cell cycle arrest in G1, and increased sensitivity to stresses such as heat shock and nutrient starvation while some of the phenotypes resulting from reduced PKA activity are hyperaccumulation of cAMP, defective glucose repression, and decreased levels of ribosomal protein mRNAs (35, 36 and references therein, and reviewed in 10).

In rapidly proliferating cells, Bcy1p and Tpk1p are predominantly localized in the nucleus. In these cells, cAMP activation of PKA results in Tpk1p translocation to the cytoplasm while Bcy1p remains in the nucleus. In nonproliferating cells or cells growing on a non-fermentable carbon source, Bcy1p and Tpk1p are present in both the nucleus and the cytoplasm (37). Nuclear versus cytoplasmic localization of Tpk1p is also partially regulated by the TOR pathway (38).

Although the Tpk isomers are functionally redundant for cell viability, they appear to regulate different processes. One high-throughput study showed that different numbers of distinct proteins were targeted by Tpk1p (256), Tpk2p (29), and Tpk3p (79) and greater than 87% of all PKA substrates were uniquely phosphorylated by just one of the Tpks (26). In addition to differing protein targets, the three isomers also recognize and affect the transcription of different sets of gene targets. Tpk1p was shown to bind the coding regions of most actively transcribed genes and in particular is required for the expression of genes involved in branched chain amino acid biosynthesis (39, 40).

Last updated: 2007-05-17 Contact SGD

References cited on this page View Complete Literature Guide for TPK1
1) Cannon, J.F.  (1989) Personal Communication, Mortimer Map Edition 10
2) Cannon JF and Tatchell K  (1987) Characterization of Saccharomyces cerevisiae genes encoding subunits of cyclic AMP-dependent protein kinase. Mol Cell Biol 7(8):2653-63
3) Toda T, et al.  (1987) Three different genes in S. cerevisiae encode the catalytic subunits of the cAMP-dependent protein kinase. Cell 50(2):277-87
4) Ordiz I, et al.  (1996) Glucose-induced inactivation of isocitrate lyase in Saccharomyces cerevisiae is mediated by the cAMP-dependent protein kinase catalytic subunits Tpk1 and Tpk2. FEBS Lett 385(1-2):43-6
5) Toda T, et al.  (1987) Cloning and characterization of BCY1, a locus encoding a regulatory subunit of the cyclic AMP-dependent protein kinase in Saccharomyces cerevisiae. Mol Cell Biol 7(4):1371-7
6) Byrne KP and Wolfe KH  (2005) The Yeast Gene Order Browser: combining curated homology and syntenic context reveals gene fate in polyploid species. Genome Res 15(10):1456-61
7) Rao S, et al.  (2012) Biogenesis of the preprotein translocase of the outer mitochondrial membrane: protein kinase A phosphorylates the precursor of Tom40 and impairs its import. Mol Biol Cell 23(9):1618-27
8) Mizunuma M, et al.  (2013) Ras/cAMP-dependent protein kinase (PKA) regulates multiple aspects of cellular events by phosphorylating the Whi3 cell cycle regulator in budding yeast. J Biol Chem 288(15):10558-66
9) Thorner J  (2005) personal communication
10) Broach JR  (1991) RAS genes in Saccharomyces cerevisiae: signal transduction in search of a pathway. Trends Genet 7(1):28-33
11) Santangelo GM  (2006) Glucose signaling in Saccharomyces cerevisiae. Microbiol Mol Biol Rev 70(1):253-82
12) Estruch F  (2000) Stress-controlled transcription factors, stress-induced genes and stress tolerance in budding yeast. FEMS Microbiol Rev 24(4):469-86
13) Norbeck J and Blomberg A  (2000) The level of cAMP-dependent protein kinase A activity strongly affects osmotolerance and osmo-instigated gene expression changes in Saccharomyces cerevisiae. Yeast 16(2):121-37
14) Barbieri M, et al.  (2003) Insulin/IGF-I-signaling pathway: an evolutionarily conserved mechanism of longevity from yeast to humans. Am J Physiol Endocrinol Metab 285(5):E1064-71
15) Klein C and Struhl K  (1994) Protein kinase A mediates growth-regulated expression of yeast ribosomal protein genes by modulating RAP1 transcriptional activity. Mol Cell Biol 14(3):1920-8
16) Ferguson SB, et al.  (2005) Protein kinase A regulates constitutive expression of small heat-shock genes in an Msn2/4p-independent and Hsf1p-dependent manner in Saccharomyces cerevisiae. Genetics 169(3):1203-14
17) Cherry JR, et al.  (1989) Cyclic AMP-dependent protein kinase phosphorylates and inactivates the yeast transcriptional activator ADR1. Cell 56(3):409-19
18) Gorner W, et al.  (1998) Nuclear localization of the C2H2 zinc finger protein Msn2p is regulated by stress and protein kinase A activity. Genes Dev 12(4):586-97
19) Gorner W, et al.  (2002) Acute glucose starvation activates the nuclear localization signal of a stress-specific yeast transcription factor. EMBO J 21(1-2):135-44
20) Chang YW, et al.  (2004) The Ras/PKA signaling pathway directly targets the Srb9 protein, a component of the general RNA polymerase II transcription apparatus. Mol Cell 15(1):107-16
21) Kinney AJ and Carman GM  (1988) Phosphorylation of yeast phosphatidylserine synthase in vivo and in vitro by cyclic AMP-dependent protein kinase. Proc Natl Acad Sci U S A 85(21):7962-6
22) Dihazi H, et al.  (2003) Glucose-induced stimulation of the Ras-cAMP pathway in yeast leads to multiple phosphorylations and activation of 6-phosphofructo-2-kinase. Biochemistry 42(20):6275-82
23) Zahringer H, et al.  (1998) Stability of neutral trehalase during heat stress in Saccharomyces cerevisiae is dependent on the activity of the catalytic subunits of cAMP-dependent protein kinase, Tpk1 and Tpk2. Eur J Biochem 255(3):544-51
24) Reinders A, et al.  (1998) Saccharomyces cerevisiae cAMP-dependent protein kinase controls entry into stationary phase through the Rim15p protein kinase. Genes Dev 12(18):2943-55
25) Budovskaya YV, et al.  (2005) An evolutionary proteomics approach identifies substrates of the cAMP-dependent protein kinase. Proc Natl Acad Sci U S A 102(39):13933-8
26) Ptacek J, et al.  (2005) Global analysis of protein phosphorylation in yeast. Nature 438(7068):679-84
27) Denis CL, et al.  (1991) Substrate specificities for yeast and mammalian cAMP-dependent protein kinases are similar but not identical. J Biol Chem 266(27):17932-5
28) Yu G, et al.  (1994) The Schizosaccharomyces pombe pka1 gene, encoding a homolog of cAMP-dependent protein kinase. Gene 151(1-2):215-20
29) Scott JD  (1991) Cyclic nucleotide-dependent protein kinases. Pharmacol Ther 50(1):123-45
30) Mbonyi K, et al.  (1990) Glucose-induced hyperaccumulation of cyclic AMP and defective glucose repression in yeast strains with reduced activity of cyclic AMP-dependent protein kinase. Mol Cell Biol 10(9):4518-23
31) Nikawa J, et al.  (1987) Rigorous feedback control of cAMP levels in Saccharomyces cerevisiae. Genes Dev 1(9):931-7
32) Sreenath TL, et al.  (1988) Two different protein kinase activities phosphorylate Ras2 protein in Saccharomyces cerevisiae. Biochem Biophys Res Commun 157(3):1182-9
33) Ma P, et al.  (1999) The PDE1-encoded low-affinity phosphodiesterase in the yeast Saccharomyces cerevisiae has a specific function in controlling agonist-induced cAMP signaling. Mol Biol Cell 10(1):91-104
34) Portela P and Moreno S  (2006) Glucose-dependent activation of protein kinase A activity in Saccharomyces cerevisiae and phosphorylation of its TPK1 catalytic subunit. Cell Signal 18(7):1072-86
35) Zurita-Martinez SA and Cardenas ME  (2005) Tor and cyclic AMP-protein kinase A: two parallel pathways regulating expression of genes required for cell growth. Eukaryot Cell 4(1):63-71
36) Hartley AD, et al.  (1996) cAMP inhibits bud growth in a yeast strain compromised for Ca2+ influx into the Golgi. Mol Gen Genet 251(5):556-64
37) Griffioen G, et al.  (2000) Nutritional control of nucleocytoplasmic localization of cAMP-dependent protein kinase catalytic and regulatory subunits in Saccharomyces cerevisiae. J Biol Chem 275(2):1449-56
38) Schmelzle T, et al.  (2004) Activation of the RAS/cyclic AMP pathway suppresses a TOR deficiency in yeast. Mol Cell Biol 24(1):338-51
39) Robertson LS, et al.  (2000) The yeast A kinases differentially regulate iron uptake and respiratory function. Proc Natl Acad Sci U S A 97(11):5984-8
40) Pokholok DK, et al.  (2006) Activated signal transduction kinases frequently occupy target genes. Science 313(5786):533-6