A cell-wall-associated phosphatase in hyphae of Fonsecaea pedrosoi, a fungal pathogen causing chromoblastomycosis, was previously characterized by the authors. In the present work, the expression of an acidic ectophosphatase activity in F. pedrosoi conidial forms was investigated. The surface phosphatase activity in F. pedrosoi is associated with the cell wall, as demonstrated by transmission electron microscopy. This enzyme activity was strongly inhibited by exogenous inorganic phosphate (P(i)). Accordingly, removal of P(i) from the culture medium of F. pedrosoi resulted in a marked (130-fold) increase of ectophosphatase activity. With the artificial phosphatase substrate p-nitrophenyl phosphate, a Km value of 0.63+/-0.04 mM was estimated for the phosphatase activity of fungal cells strongly expressing the enzyme activity. This enzyme activity was not modulated by cations. Conidia with greater ectophosphatase activity showed greater adherence to mammalian cells than did fungi cultivated in the presence of P(i) (low phosphatase activity). Surface phosphatase activity was apparently involved in the adhesion to host cells, since the enhanced attachment of F. pedrosoi to host cells was reversed by pre-treatment of conidia with phosphatase inhibitor. Since conidial forms are the putative infectious propagules in chromoblastomycosis, the expression and activity of acidic surface phosphatases in these cells may contribute to the early mechanisms required for disease establishment.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1099/mic.0.27405-0 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Ectonucleotidase activity driven by acid ectophosphatase in luminal A MCF-7 breast cancer cells.
Cell Biol Int
November 2024
Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Ectophosphatases catalyse the hydrolysis of phosphorylated molecules, such as phospho-amino acids, in the extracellular environment. Nevertheless, the hydrolysis of nucleotides in the extracellular environment is typically catalysed by ectonucleotidases. Studies have shown that acid ectophosphatase, or transmembrane-prostatic acid phosphatase (TM-PAP), a membrane-bound splice variant of prostatic acid phosphatase, has ecto-5'-nucleotidase activity.
View Article and Find Full Text PDFIdentification and characterization of an ectophosphatase activity involved in Acanthamoeba castellanii adhesion to host cells.
Eur J Protistol
October 2023
Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), UFRJ, Rio de Janeiro, RJ, Brazil. Electronic address:
Acanthamoeba castellanii is a free-living amoeba and an opportunistic pathogen for humans that can cause encephalitis and, more commonly, Acanthamoeba keratitis. During its life cycle, A. castellanii may present as proliferative and infective trophozoites or resistant cysts.
View Article and Find Full Text PDFElevated extracellular inorganic phosphate inhibits ecto-phosphatase activity in breast cancer cells: Regulation by hydrogen peroxide.
Cell Biol Int
February 2024
Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
For cells to obtain inorganic phosphate, ectoenzymes in the plasma membrane, which contain a catalytic site facing the extracellular environment, hydrolyze phosphorylated molecules. In this study, we show that increased Pi levels in the extracellular environment promote a decrease in ecto-phosphatase activity, which is associated with Pi-induced oxidative stress. High levels of Pi inhibit ecto-phosphatase because Pi generates H O .
View Article and Find Full Text PDFEuglena gracilis: Biochemical properties of a membrane bound ecto-phosphatase activity modulated by fluoroaluminate complexes and different trophic conditions.
Eur J Protistol
August 2023
Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590 Rio de Janeiro, RJ, Brazil. Electronic address:
The ecto-phosphatases belong to a group of enzymes closely associated with the cell surface that has its catalytic site facing the extracellular environment, where different phosphorylated substrates can be hydrolyzed. In the present work, we biochemically characterized the ecto-phosphatase activity of the freshwater microalgae Euglena gracilis, a model microorganism, ubiquitously distributed and resistant to several environmental stressors. The ecto-phosphatase activity is acidic, stimulated by copper and presents the following apparent kinetic parameters: K = 2.
View Article and Find Full Text PDFPlasma membrane phospholipid phosphatase-related proteins as pleiotropic regulators of neuron growth and excitability.
Front Mol Neurosci
September 2022
Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece.
Neuronal plasma membrane proteins are essential for integrating cell extrinsic and cell intrinsic signals to orchestrate neuronal differentiation, growth and plasticity in the developing and adult nervous system. Here, we shed light on the family of plasma membrane proteins phospholipid phosphatase-related proteins (PLPPRs) (alternative name, PRGs; plasticity-related genes) that fine-tune neuronal growth and synaptic transmission in the central nervous system. Several studies uncovered essential functions of PLPPRs in filopodia formation, axon guidance and branching during nervous system development and regeneration, as well as in the control of dendritic spine number and excitability.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!