title: Global analysis of serine/threonine and tyrosine protein phosphatase catalytic subunit genes in Neurospora crassa reveals interplay between phosphatases and the p38 mitogen-activated protein kinase.
abstract: Protein phosphatases are integral components of the cellular signaling machinery in eukaryotes, regulating diverse aspects of growth and development. The genome of the filamentous fungus and model organism Neurospora crassa encodes catalytic subunits for 30 protein phosphatase genes. In this study, we have characterized 24 viable N. crassa phosphatase catalytic subunit knockout mutants for phenotypes during growth, asexual development, and sexual development. We found that 91% of the mutants had defects in at least one of these traits, whereas 29% possessed phenotypes in all three. Chemical sensitivity screens were conducted to reveal additional phenotypes for the mutants. This resulted in the identification of at least one chemical sensitivity phenotype for 17 phosphatase knockout mutants, including novel chemical sensitivities for two phosphatase mutants lacking a growth or developmental phenotype. Hence, chemical sensitivity or growth/developmental phenotype was observed for all 24 viable mutants. We investigated p38 mitogen-activated protein kinase (MAPK) phosphorylation profiles in the phosphatase mutants and identified nine potential candidates for regulators of the p38 MAPK. We demonstrated that the PP2C class phosphatase pph-8 (NCU04600) is an important regulator of female sexual development in N. crassa. In addition, we showed that the Δcsp-6 (ΔNCU08380) mutant exhibits a phenotype similar to the previously identified conidial separation mutants, Δcsp-1 and Δcsp-2, that lack transcription factors important for regulation of conidiation and the circadian clock.
authors.affiliation: Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521.
authors.forename: Arit
authors.initials: A
authors.lastname: Ghosh
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Servin
authors.forename: Gyungsoon
authors.initials: G
authors.lastname: Park
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Borkovich
mesh_terms: D020134:Catalytic Domain / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D016681:Genome, Fungal; D009154:Mutation; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D010749:Phosphoprotein Phosphatases / Q000235:genetics* / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000235:genetics* / Q000378:metabolism; D013172:Spores, Fungal / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D048051:p38 Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D017027:Protein Tyrosine Phosphatases
keywords: filamentous fungi; functional genomics; protein phosphorylation; serine-threonine protein phosphatases; tyrosine protein phosphatases