title: The Aspergillus fumigatus pkcA G579R Mutant Is Defective in the Activation of the Cell Wall Integrity Pathway but Is Dispensable for Virulence in a Neutropenic Mouse Infection Model.
abstract: Aspergillus fumigatus is an opportunistic human pathogen, which causes the life-threatening disease, invasive pulmonary aspergillosis. In fungi, cell wall homeostasis is controlled by the conserved Cell Wall Integrity (CWI) pathway. In A. fumigatus this signaling cascade is partially characterized, but the mechanisms by which it is activated are not fully elucidated. In this study we investigated the role of protein kinase C (PkcA) in this signaling cascade. Our results suggest that pkcA is an essential gene and is activated in response to cell wall stress. Subsequently, we constructed and analyzed a non-essential A. fumigatus pkcAG579R mutant, carrying a Gly579Arg substitution in the PkcA C1B regulatory domain. The pkcAG579R mutation has a reduced activation of the downstream Mitogen-Activated Protein Kinase, MpkA, resulting in the altered expression of genes encoding cell wall-related proteins, markers of endoplasmic reticulum stress and the unfolded protein response. Furthermore, PkcAG579R is involved in the formation of proper conidial architecture and protection to oxidative damage. The pkcAG579R mutant elicits increased production of TNF-α and phagocytosis but it has no impact on virulence in a murine model of invasive pulmonary aspergillosis. These results highlight the importance of PkcA to the CWI pathway but also indicated that additional regulatory circuits may be involved in the biosynthesis and/or reinforcement of the A. fumigatus cell wall during infection.
authors: Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
authors: Marina Campos
authors: MC
authors: Rocha
authors: Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
authors: Krissia Franco de
authors: KF
authors: Godoy
authors: Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors: Patrícia Alves
authors: PA
authors: de Castro
authors: Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors: Juliana Issa
authors: JI
authors: Hori
authors: Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors: Vinícius Leite Pedro
authors: VL
authors: Bom
authors: Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts, United Kingdom.
authors: Neil Andrew
authors: NA
authors: Brown
authors: Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
authors: Anderson Ferreira da
authors: AF
authors: Cunha
authors: Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil; Laboratório Nacional de Ciência e Tecnologia do Bioetanol, Campinas, São Paulo, Brazil.
authors: Gustavo Henrique
authors: GH
authors: Goldman
authors: Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
authors: Iran
authors: I
authors: Malavazi
mesh_terms: D000818:Animals; D001232:Aspergillus fumigatus / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D004195:Disease Models, Animal; D059865:Endoplasmic Reticulum Stress / Q000235:genetics; D005260:Female; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005818:Genetic Engineering; D006801:Humans; D055744:Invasive Pulmonary Aspergillosis / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009503:Neutropenia / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D010587:Phagocytosis; D051571:Protein Kinase C-alpha / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D013172:Spores, Fungal / Q000737:chemistry / Q000378:metabolism; D016019:Survival Analysis; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D056811:Unfolded Protein Response / Q000235:genetics; D014774:Virulence
chemical_list: D005656:Fungal Proteins; D014409:Tumor Necrosis Factor-alpha; D051571:Protein Kinase C-alpha; D020928:Mitogen-Activated Protein Kinases