Caracterização in silico, estudo da atividade e avaliação do papel da PKA na transição morfológica de Paracoccidioides lutzii

• Autor(a) principal: Sestari, Sheila Janaina
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/8711
• topic: Paracoccidioides lutzii; Transição morfológica; PKA; H89; Morphological transition; CIENCIAS BIOLOGICAS::GENETICA

Paracoccidioides lutzii alternates between filamentous and yeast growth when exposed to temperatures of 36ºC. Morphological transition is an essential event for establishment of paracoccidioidomycosis (PCM), one of the most frequent systemic mycoses in Latin America. Paracoccidioides brasiliensis and other dimorphic fungi, cAMP-dependent protein kinase (PKA) is essential in the dimorphic process. However, molecular events responsible for mycelial-yeast differentiation in P. lutzii remain unknown. The aim of this work was to characterize in silico the PKA subunits of P. lutzii, and to evaluate the role of this enzyme during the morphological transition of this fungus. During the in silico approach, we used computational tools for identity, domains, cell localization prediction, and similarity between P. lutzii and human sequences analysis. The importance of this enzyme was investigated through the use of specific inhibitor, H89. The behavior of cells in the presence of the drug was observed and the PKA activity measured by specific kit. Our in silico results reveal a single regulatory subunit, PbPKA-R located primarily in the nucleus, and two catalytic subunits, PbPKA-C1 and PbPKA-C2, with localization in the cytoplasm and nucleus respectively, all highly conserved. The PbPKA-R subunits were identified with two copies of the CNMP domain in the C-terminal, while the catalytic with a single copy of two domains: protein kinase and AGC kinase. The alignment of the PKA catalytic subunits of humans and Paracoccidioides shows a large divergence between them, making PKA an interesting target for antifungal. The results show that PKA activity is phase regulated, being about five times higher in yeast than in mycelium. We also show that H89 blocks the mycelium to yeast differentiation when PKA activity decreases. However, when the drug is removal from the culture medium, the fungus resumes the differentiation to the yeast phase. Our results show that PKA activity affects the phase transition in P. lutzii.