Secretion of serine peptidase by a clinical strain of Candida albicans: influence of growth conditions and cleavage of human serum proteins and extracellular matrix components.
Candida albicans expresses a vast number of hydrolytic enzymes, playing roles in several phases of yeast-host interactions. Here, we identified two novel extracellular peptidase classes in C. albicans. Using gelatin-sodium dodecyl sulfate polyacrylamide gel electrophoresis two gelatinolytic activities were detected at physiological pH: a 60-kDa metallopeptidase, completely blocked by 1,10-phenanthroline, and a 50-kDa serine peptidase inhibited by phenylmethylsulfonyl fluoride. In an effort to establish a probable functional implication for these novel peptidase classes, we demonstrated that the 50-kDa secretory serine peptidase was active over a broad pH range (5.0-7.2) and was capable to hydrolyze some soluble human serum proteins and extracellular matrix components. Conversely, when this isolate was grown in yeast carbon base supplemented with bovine serum albumin, a secretory aspartyl peptidase activity was measured, instead of metallo- and serine peptidases, suggesting that distinct medium composition induces different expression of released peptidases in C. albicans. Additionally, we showed by quantitative proteolytic measurement, flow cytometry and immunoblotting assays that the brain heart infusion medium might repress the Sap1-3 production. Collectively, our results showed for the first time the capability of an extracellular proteolytic enzyme other than aspartic-type peptidases to cleave a broad spectrum of relevant host proteinaceous substrates by the human pathogen C. albicans.
Departamento de Microbiologia Geral, Instituto de Microbiologia Prof. Paulo de Góes (IMPPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil. andre@micro.ufrj.br
André Luis Souza
AL
dos Santos
Isabela Miller
IM
de Carvalho
Bianca Alcântara
BA
da Silva
Maristela Barbosa
MB
Portela
Celuta Sales
CS
Alviano
Rosangela Maria
RM
de Araújo Soares
D000328:Adult; D001798:Blood Proteins / Q000378:metabolism*; D002176:Candida albicans / Q000201:enzymology* / Q000254:growth & development* / Q000472:pathogenicity; D002177:Candidiasis / Q000382:microbiology; D003470:Culture Media; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D005656:Fungal Proteins / Q000378:metabolism; D006801:Humans; D045726:Metalloproteases / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism*; D014552:Urinary Tract Infections / Q000382:microbiology
D001798:Blood Proteins; D003470:Culture Media; D005656:Fungal Proteins; D045726:Metalloproteases; D012697:Serine Endopeptidases