Pneumocystis carinii STE11, an HMG-box protein, is phosphorylated by the mitogen activated protein kinase PCM.
A pheromone-induced mitogen activated protein kinase (MAPK) pathway controls mating in fungi by regulating gene transcription. In the opportunistic fungus Pneumocystis carinii, we have identified a protein containing a high-mobility group (HMG) motif which is homologous to the transcriptional activators STE11 of Schizosaccharomyces pombe and STE12 of Saccharomyces cerevisiae. In fungi, this transcriptional activator functions in sexual development, filamentous growth, and pathogenicity. The fungal pheromone-activated MAPK phosphorylates the transcriptional activator to allow binding to pheromone-response elements in the promoter regions of certain genes. We have previously identified a P. carinii MAPK, PCM, which has significant homology to fungal MAPKs involved in mating. As an initial step in understanding the downstream molecules which interact with the PCM kinase, we have cloned a STE11 homologue in P. carinii. PCSTE11 has an open-reading frame of 1.5 kb which encodes a protein of 501 amino acids with a molecular weight of 56 kDa. Greatest homology was to S. pombe STE11 (52%). We have expressed a His-tag fusion of PCSTE11 and purified the protein with nickel affinity resin. PCM phosphorylates the purified protein indicating that PCSTE11 is associated with the MAPK cascade in P. carinii.
Vohra
Pawan K
PK
Thoracic Diseases Research Unit, 826 Stabile Building, Division of Pulmonary, Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
Puri
Veenu
V
Kottom
Theodore J
TJ
Limper
Andrew H
AH
Thomas
Charles F
CF
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D024002:HMGB Proteins / Q000235:genetics* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011010:Pneumocystis / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D018076:DNA, Complementary; D005656:Fungal Proteins; D024002:HMGB Proteins; D011994:Recombinant Proteins; C477831:STE11 protein, Pneumocystis carinii; D020928:Mitogen-Activated Protein Kinases