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 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.

Far1 and Fus3 link the mating pheromone signal transduction pathway to three G1-phase Cdc28 kinase complexes

1993 ◽  
Vol 13 (9) ◽  
pp. 5659-5669 ◽  
Author(s):  
M Tyers ◽  
B Futcher
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Signal Transduction Pathway ◽  
Mitogen Activated Protein Kinase ◽  
G1 Phase ◽  
Transduction Pathway ◽  
Yeast Saccharomyces Cerevisiae ◽  
Alpha Factor ◽  
Mitogen Activated Protein

In the yeast Saccharomyces cerevisiae, the Cdc28 protein kinase controls commitment to cell division at Start, but no biologically relevant G1-phase substrates have been identified. We have studied the kinase complexes formed between Cdc28 and each of the G1 cyclins Cln1, Cln2, and Cln3. Each complex has a specific array of coprecipitated in vitro substrates. We identify one of these as Far1, a protein required for pheromone-induced arrest at Start. Treatment with alpha-factor induces a preferential association and/or phosphorylation of Far1 by the Cln1, Cln2, and Cln3 kinase complexes. This induced interaction depends upon the Fus3 protein kinase, a mitogen-activated protein kinase homolog that functions near the bottom of the alpha-factor signal transduction pathway. Thus, we trace a path through which a mitogen-activated protein kinase regulates a Cdc2 kinase.

The LAMMER Protein Kinase Encoded by the Doa Locus of Drosophila Is Required in Both Somatic and Germline Cells and Is Expressed as Both Nuclear and Cytoplasmic Isoforms Throughout Development

Genetics ◽  
2000 ◽  
Vol 156 (2) ◽  
pp. 749-761 ◽  
Author(s):  
Bokyoung Yun ◽  
Kun Lee ◽  
Robert Farkaš ◽  
Christophe Hitte ◽  
Leonard Rabinow
Keyword(s):  
Protein Kinase ◽  
Sexual Differentiation ◽  
Signal Transduction Pathway ◽  
Cell Types ◽  
Protein Isoforms ◽  
Transduction Pathway ◽  
Pupal Development ◽  
Salivary Gland Cells ◽  
Mosaic Analysis ◽  
Embryonic Nervous System

Abstract Activity of the Darkener of apricot (Doa) locus of Drosophila melanogaster is required for development of the embryonic nervous system, segmentation, photoreceptor maintenance, normal transcription, and sexual differentiation. The gene encodes a protein kinase, with homologues throughout eukaryotes known as the LAMMER kinases. We show here that DOA is expressed as at least two different protein isoforms of 105 and 55 kD throughout development, which are primarily localized to the cytoplasm and nucleus, respectively. Doa transcripts and protein are expressed in all cell types both during embryogenesis and in imaginal discs. Although it was recently shown that DOA kinase is essential for normal sexual differentiation, levels of both kinase isoforms are equal between the sexes during early pupal development. The presence of the kinase on the cell membrane and in the nuclei of polytene salivary gland cells, as well as exclusion from the nuclei of specific cells, may be indicative of regulated kinase localization. Mosaic analysis in both the soma and germline demonstrates that Doa function is essential for cell viability. Finally, in contrast to results reported in other systems and despite some phenotypic similarities, genetic data demonstrate that the LAMMER kinases do not participate in the ras-MAP kinase signal transduction pathway.

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