scholarly journals byr2, a Schizosaccharomyces pombe gene encoding a protein kinase capable of partial suppression of the ras1 mutant phenotype.

1991 ◽  
Vol 11 (7) ◽  
pp. 3554-3563 ◽  
Author(s):  
Y Wang ◽  
H P Xu ◽  
M Riggs ◽  
L Rodgers ◽  
M Wigler
Keyword(s):  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
Cell Shape ◽  
Single Gene ◽  
Gene Encoding ◽  
Ras Genes ◽  
Mutant Strains ◽  
Site Of Action ◽  
Partial Suppression ◽  
Normal Shape

Schizosaccharomyces pombe contains a single gene, ras1, which is a homolog of the mammalian RAS genes. ras1 is required for conjugation, sporulation, and normal cell shape. ras1 has been previously identified as ste5. We report here a gene we call byr2 that can encode a predicted protein kinase and can partially suppress defects in ras1 mutants. ras1 mutant strains expressing high levels of byr2 can sporulate competently but are still defective in conjugation and abnormally round. byr2 mutants are viable and have normal shape but are absolutely defective in conjugation and sporulation. byr2 is probably identical to ste8. In many respects, byr2 resembles the byr1 gene, another suppressor of the ras1 mutation, which has been identified previously as ste1. Our data indicate that if ras1, byr2, and byr1 act along the same pathway, then the site of action for byr2 is between the sites for ras1 and byr1.

scholarly journals byr2, a Schizosaccharomyces pombe gene encoding a protein kinase capable of partial suppression of the ras1 mutant phenotype

1991 ◽  
Vol 11 (7) ◽  
pp. 3554-3563 ◽  
Author(s):  
Y Wang ◽  
H P Xu ◽  
M Riggs ◽  
L Rodgers ◽  
M Wigler
Keyword(s):  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
Cell Shape ◽  
Single Gene ◽  
Gene Encoding ◽  
Ras Genes ◽  
Mutant Strains ◽  
Site Of Action ◽  
Partial Suppression ◽  
Normal Shape

Schizosaccharomyces pombe contains a single gene, ras1, which is a homolog of the mammalian RAS genes. ras1 is required for conjugation, sporulation, and normal cell shape. ras1 has been previously identified as ste5. We report here a gene we call byr2 that can encode a predicted protein kinase and can partially suppress defects in ras1 mutants. ras1 mutant strains expressing high levels of byr2 can sporulate competently but are still defective in conjugation and abnormally round. byr2 mutants are viable and have normal shape but are absolutely defective in conjugation and sporulation. byr2 is probably identical to ste8. In many respects, byr2 resembles the byr1 gene, another suppressor of the ras1 mutation, which has been identified previously as ste1. Our data indicate that if ras1, byr2, and byr1 act along the same pathway, then the site of action for byr2 is between the sites for ras1 and byr1.

scholarly journals Concerted action of RAS and G proteins in the sexual response pathways of Schizosaccharomyces pombe

1994 ◽  
Vol 14 (1) ◽  
pp. 50-58
Author(s):  
H P Xu ◽  
M White ◽  
S Marcus ◽  
M Wigler
Keyword(s):  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
G Proteins ◽  
Map Kinases ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Concerted Action ◽  
Gene Encoding ◽  
Functional Homolog ◽  
P Factor

We have shown that the expression of mam2, the gene encoding the Schizosaccharomyces pombe P-factor pheromone receptor, is dependent upon components of the pheromone signal transduction pathway, including Ras1, Gpa1, Byr1 and Byr2, each of which is required for both conjugation and sporulation. Studies of the expression of mam2 in mutant S. pombe cells confirm previous conclusions, based on the ability of cells to sporulate, that the Byr1 protein kinase acts downstream of the Byr2 protein kinase and that both act downstream of Ras1, the S. pombe RAS homolog, and Gpa1, the G alpha component that mediates the occupancy of the mam2 receptor. In addition, our present studies show that Ras1 and Gpa1 each act downstream from the other and hence act in concert. The Spk1 kinase, which is required for conjugation and sporulation and which is a structural and functional homolog of the vertebrate MAP kinases, is not required for mam2 expression.

scholarly journals Dictyostelium discoideum has a single diacylglycerol kinase gene with similarity to mammalian θ isoforms

2002 ◽  
Vol 368 (3) ◽  
pp. 809-815 ◽  
Author(s):  
Marc A. de la ROCHE ◽  
Janet L. SMITH ◽  
Maribel RICO ◽  
Silvia CARRASCO ◽  
Isabel MERIDA ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Dictyostelium Discoideum ◽  
Heavy Chain ◽  
Catalytic Domain ◽  
Single Gene ◽  
Myosin Ii ◽  
Terminal Segment ◽  
Gene Encoding ◽  
Kinase Gene ◽  
Myosin Heavy Chain Protein

Diacylglycerol kinases (DGKs) phosphorylate the neutral lipid diacylglycerol (DG) to produce phosphatidic acid (PA). In mammalian systems DGKs are a complex family of at least nine isoforms that are thought to participate in down-regulation of DG-based signalling pathways and perhaps activation of PA-stimulated signalling events. We report here that the simple protozoan amoeba Dictyostelium discoideum appears to contain a single gene encoding a DGK enzyme. This gene, dgkA, encodes a deduced protein that contains three C1-type cysteine-rich repeats, a DGK catalytic domain most closely related to the θ subtype of mammalian DGKs and a C-terminal segment containing a proline/glutamine-rich region and a large aspargine-repeat region. This gene corresponds to a previously reported myosin II heavy chain kinase designated myosin heavy chain-protein kinase C (MHC-PKC), but our analysis clearly demonstrates that this protein does not, as suggested by earlier data, contain a protein kinase catalytic domain. A FLAG-tagged version of DgkA expressed in Dictyostelium displayed robust DGK activity. Earlier studies indicating that disruption of this locus alters myosin II assembly levels in Dictyostelium raise the intriguing possibility that DG and/or PA metabolism may play a role in controlling myosin II assembly in this system.

scholarly journals Concerted action of RAS and G proteins in the sexual response pathways of Schizosaccharomyces pombe.

1994 ◽  
Vol 14 (1) ◽  
pp. 50-58 ◽  
Author(s):  
H P Xu ◽  
M White ◽  
S Marcus ◽  
M Wigler
Keyword(s):  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
G Proteins ◽  
Map Kinases ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Concerted Action ◽  
Gene Encoding ◽  
Functional Homolog ◽  
P Factor

We have shown that the expression of mam2, the gene encoding the Schizosaccharomyces pombe P-factor pheromone receptor, is dependent upon components of the pheromone signal transduction pathway, including Ras1, Gpa1, Byr1 and Byr2, each of which is required for both conjugation and sporulation. Studies of the expression of mam2 in mutant S. pombe cells confirm previous conclusions, based on the ability of cells to sporulate, that the Byr1 protein kinase acts downstream of the Byr2 protein kinase and that both act downstream of Ras1, the S. pombe RAS homolog, and Gpa1, the G alpha component that mediates the occupancy of the mam2 receptor. In addition, our present studies show that Ras1 and Gpa1 each act downstream from the other and hence act in concert. The Spk1 kinase, which is required for conjugation and sporulation and which is a structural and functional homolog of the vertebrate MAP kinases, is not required for mam2 expression.

scholarly journals Reduced vacuolar β-1,3-glucan synthesis affects carbohydrate metabolism as well as plastid homeostasis and structure inPhaeodactylum tricornutum

2018 ◽  
Vol 115 (18) ◽  
pp. 4791-4796 ◽  
Author(s):  
Weichao Huang ◽  
Ilka Haferkamp ◽  
Bernard Lepetit ◽  
Mariia Molchanova ◽  
Shengwei Hou ◽  
...  
Keyword(s):  
Carbohydrate Metabolism ◽  
Single Gene ◽  
Soluble Sugars ◽  
Gene Encoding ◽  
Alternative Pathways ◽  
Mutant Strains ◽  
Algal Groups ◽  
Plastid Morphology ◽  
Glucan Synthesis ◽  
Vacuolar Protein

The β-1,3-glucan chrysolaminarin is the main storage polysaccharide of diatoms. In contrast to plants and green algae, diatoms and most other algal groups do not accumulate storage polysaccharides in their plastids. The diatomPhaeodactylum tricornutumpossesses only a single gene encoding a putative β-1,3-glucan synthase (PtBGS). Here, we characterize this enzyme by expressing GFP fusion proteins inP. tricornutumand by creating and investigating corresponding gene silencing mutants. We demonstrate thatPtBGS is a vacuolar protein located in the tonoplast. Metabolite analyses of two mutant strains with reduced amounts ofPtBGS reveal a reduction in their chrysolaminarin content and an increase of soluble sugars and lipids. This indicates that carbohydrates are shunted into alternative pathways when chrysolaminarin production is impaired. The mutant strains show reduced growth and lower photosynthetic capacities, while possessing higher photoprotective abilities than WT cells. Interestingly, a strong reduction inPtBGS expression also results in aberrations of the usually very regular thylakoid membrane patterns, including increased thylakoid thickness, reduced numbers of thylakoids per plastid, and increased numbers of lamellae per thylakoid stack. Our data demonstrate the complex intertwinement of carbohydrate storage in the vacuoles with carbohydrate metabolism, photosynthetic homeostasis, and plastid morphology.

scholarly journals Cyclic AMP-Dependent Protein Kinase Controls Virulence of the Fungal Pathogen Cryptococcus neoformans

2001 ◽  
Vol 21 (9) ◽  
pp. 3179-3191 ◽  
Author(s):  
Cletus A. D'Souza ◽  
J. Andrew Alspaugh ◽  
Changli Yue ◽  
Toshiaki Harashima ◽  
Gary M. Cox ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Cryptococcus Neoformans ◽  
Fungal Pathogen ◽  
Catalytic Subunit ◽  
Regulatory Subunit ◽  
Dependent Protein Kinase ◽  
Gene Encoding ◽  
Mutant Strains ◽  
Dependent Protein

ABSTRACT Cryptococcus neoformans is an opportunistic fungal pathogen that infects the human central nervous system. This pathogen elaborates two specialized virulence factors: the antioxidant melanin and an antiphagocytic immunosuppressive polysaccharide capsule. A signaling cascade controlling mating and virulence was identified. ThePKA1 gene encoding the major cyclic AMP (cAMP)-dependent protein kinase catalytic subunit was identified and disrupted.pka1 mutant strains were sterile, failed to produce melanin or capsule, and were avirulent. The PKR1 gene encoding the protein kinase A (PKA) regulatory subunit was also identified and disrupted. pkr1 mutant strains overproduced capsule and were hypervirulent in animal models of cryptococcosis. pkr1 pka1 double mutant strains exhibited phenotypes similar to that of pka1 mutants, providing epistasis evidence that the Pka1 catalytic subunit functions downstream of the Pkr1 regulatory subunit. The PKA pathway was also shown to function downstream of the Gα protein Gpa1 and to regulate cAMP production by feedback inhibition. These findings define a Gα protein-cAMP-PKA signaling pathway regulating differentiation and virulence of a human fungal pathogen.

scholarly journals Suppressors of a Saccharomyces cerevisiae pkc1 mutation identify alleles of the phosphatase gene PTC1 and of a novel gene encoding a putative basic leucine zipper protein.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1275-1285 ◽  
Author(s):  
K N Huang ◽  
L S Symington
Keyword(s):  
Protein Kinase ◽  
Leucine Zipper ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Gene Encoding ◽  
Basic Leucine Zipper ◽  
Mapk Cascades ◽  
Synthetically Lethal

Abstract The PKC1 gene product, protein kinase C, regulates a mitogen-activated protein kinase (MAPK) cascade, which is implicated in cell wall metabolism. Previously, we identified the pkc1-4 allele in a screen for mutants with increased rates of recombination, indicating that PKC1 may also regulate DNA metabolism. The pkc1-4 allele also conferred a temperature-sensitive (ts) growth defect. Extragenic suppressors were isolated that suppress both the ts and hyperrecombination phenotypes conferred by the pkc1-4 mutation. Eight of these suppressors for into two complementation groups, designated KCS1 and KCS2. KCS1 was cloned and found to encode a novel protein with homology to the basic leucine zipper family of transcription factors. KCS2 is allelic with PTC1, a previously identified type 2C serine/threonine protein phosphatase. Although mutation of either KCS1 or PTC1 causes little apparent phenotype, the kcs1 delta ptc1 delta double mutant fails to grow at 30 degrees. Furthermore, the ptc1 deletion mutation is synthetically lethal in combination with a mutation in MPK1, which encodes a MAPK homologue proposed to act in the PKC1 pathway. Because PTC1 was initially isolated as a component of the Hog1p MAPK pathway, it appears that these two MAPK cascades share a common regulatory feature.

scholarly journals The Schizosaccharomyces pombe cho1+ Gene Encodes a Phospholipid Methyltransferase

Genetics ◽  
1998 ◽  
Vol 150 (2) ◽  
pp. 553-562
Author(s):  
Margaret I Kanipes ◽  
John E Hill ◽  
Susan A Henry
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sequence Analysis ◽  
Schizosaccharomyces Pombe ◽  
Gene Disruption ◽  
Structure And Function ◽  
Biosynthetic Enzyme ◽  
Gene Encoding ◽  
Complementation Groups ◽  
Eukaryotic Organisms ◽  
And Function

Abstract The isolation of mutants of Schizosaccharomyces pombe defective in the synthesis of phosphatidylcholine via the methylation of phosphatidylethanolamine is reported. These mutants are choline auxotrophs and fall into two unlinked complementation groups, cho1 and cho2. We also report the analysis of the cho1+ gene, the first structural gene encoding a phospholipid biosynthetic enzyme from S. pombe to be cloned and characterized. The cho1+ gene disruption mutant (cho1Δ) is viable if choline is supplied and resembles the cho1 mutants isolated after mutagenesis. Sequence analysis of the cho1+ gene indicates that it encodes a protein closely related to phospholipid methyltransferases from Saccharomyces cerevisiae and rat. Phospholipid methyltransferases encoded by a rat liver cDNA and the S. cerevisiae OPI3 gene are both able to complement the choline auxotrophy of the S. pombe cho1 mutants. These results suggest that both the structure and function of the phospholipid N-methyltransferases are broadly conserved among eukaryotic organisms.

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