Skh1, the MEK component of the mkh1 signaling pathway in Schizosaccharomyces pombe

Autor: Dallan Young, Andrew V. Hubberstey, Robbie Loewith
Rok vydání: 2000
Předmět:
Saccharomyces cerevisiae Proteins
MAP Kinase Signaling System
Recombinant Fusion Proteins
Molecular Sequence Data
Mutant
MAPK cascade
Potassium Chloride
Fungal Proteins
Suppression
Genetic
Cell Wall
Caffeine
Two-Hybrid System Techniques
Schizosaccharomyces
Amino Acid Sequence
Phosphorylation
Phosphotyrosine
Biology
Mitogen-Activated Protein Kinase Kinases
Sequence Homology
Amino Acid
biology
Kinase
beta-Glucosidase
Life Sciences
Epistasis
Genetic
Glucan 1
3-beta-Glucosidase
Cell Biology
Spores
Fungal
MAP Kinase Kinase Kinases
biology.organism_classification
Fusion protein
Cell biology
Enzyme Activation
Repressor Proteins
Biochemistry
Mitogen-activated protein kinase
Schizosaccharomyces pombe
biology.protein
Schizosaccharomyces pombe Proteins
Cyclin-dependent kinase 7
Signal transduction
Cell Division
Gene Deletion
Protein Binding
Zdroj: Biological Sciences Publications
ResearcherID
ISSN: 1477-9137
0021-9533
DOI: 10.1242/jcs.113.1.153
Popis: Skip to Next Section We previously reported the identification of Mkh1, a MEK kinase in Schizosaccharomyces pombe that is required for cell wall integrity, and we presented genetic evidence that Pmk1/Spm1, a MAP kinase, functions downstream from Mkh1 in the same pathway. Here, we report the identification of Skh1, a MEK (MAP kinase kinase) in S. pombe. The sequence of Skh1 is nearly identical to that of the recently reported Pek1 sequence. We present biochemical and genetic evidence that Skh1 is the MEK component of the Mkh1-Spm1 MAP kinase cascade. Our yeast two-hybrid results indicate that Mkh1, Skh1, and Spm1 physically interact to form a ternary complex. Deletion of mkh1, skh1 or spm1 results in identical phenotypes, including sensitivity to (beta)-glucanase treatment, growth inhibition on media containing KCl, and filamentous growth on medium containing caffeine. Double mutant strains exhibit phenotypes that are identical to the single mutant strains. Furthermore, expression of an activated HA-Skh1(DD)protein suppressed these defects in mkh1(delta) cells, and overexpression of Spm1 suppressed these defects in skh1(delta) cells. We also show that HA-Spm1 is hyper-phosphorylated on tyrosine residues in cells co-expressing the activated HA-Skh1(DD) protein. Furthermore, we found the phosphorylated/activated form of GFP-HA-Spm1 at detectable levels in wild-type cells, but not at appreciable levels in mkh1(delta) or skh1(delta) cells expressing this fusion protein. Together, our results indicate that Mkh1, Skh1 and Spm1 constitute a MAPK cascade in fission yeast.
Databáze: OpenAIRE
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