title: The MAPKK kinase SteC regulates conidiophore morphology and is essential for heterokaryon formation and sexual development in the homothallic fungus Aspergillus nidulans.
abstract: Environmental signals can be transduced into intracellular responses by the action of MAP kinase cascades. Sequential phosphorylation results in the transient activation of a MAP kinase, which in turn activates certain transcription factors and thus a set of pathway-specific genes. Many steps in this cascade are conserved, and homologues have been discovered from yeast to human. We have characterized the MAPKK kinase, SteC, a homologue of Saccharomyces cerevisiae Ste11, in the filamentous fungus Aspergillus nidulans. The 886-amino-acid-long protein shares the highest similarity to Neurospora crassa Nrc-1. Deletion of the gene in A. nidulans results in a slower growth rate, the formation of more branched hyphae, altered conidiophore morphology, an inhibition of heterokaryon formation and a block of cleistothecium development. The gene is transcriptionally activated during asexual development and controls the phosphorylation of two putative MAP kinases.
authors.affiliation: Department of Microbiology, University of Marburg and Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch-Str., D-35043 Marburg, Germany.
authors.forename: Huijun
authors.initials: H
authors.lastname: Wei
authors.forename: Natalia
authors.initials: N
authors.lastname: Requena
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fischer
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000502:physiology*; D002455:Cell Division / Q000235:genetics; D003001:Cloning, Molecular; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D025301:Hyphae / Q000502:physiology; D020930:MAP Kinase Kinase Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D012098:Reproduction / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014158:Transcription, Genetic
chemical_list: D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D020928:Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; C067018:Ste11 protein, S cerevisiae; D020929:Mitogen-Activated Protein Kinase Kinases