Immunofluorescence and flow cytometry analysis of fibronectin and laminin binding to Sporothrix schenckii yeast cells and conidia.
The adherence of Sporothrix schenckii yeast cells to several extracellular matrix (ECM) components has already been demonstrated, but the mechanisms of these interactions remained to be defined. In indirect immunofluorescence assays with polyclonal antibodies directed towards the ECM proteins, both hyphae and yeast cells of S. schenckii exhibited the ability to bind laminin and fibronectin. Flow cytometry confirmed the binding of these proteins, and revealed a significant greater binding capability for the yeast cells than for the conidia. Fibronectin and laminin binding was dose-dependent and specific. In addition, competition experiments with synthetic peptides mimicking the adhesive sequences of these proteins, or with cell wall fractions and carbohydrates constitutive of their sugar chains, were performed in order to specify the peptide or carbohydrate motifs involved in the recognition process. A 50% reduction was noticed in fibronectin binding in the presence of the synthetic peptide RGD, and a 38% reduction in laminin binding with the peptide YIGSR. Some carbohydrate-containing fractions of the yeast cell wall also inhibited the binding of fibronectin, but had no significant effect on laminin binding. Together, these results suggest the presence at the yeast surface of distinct receptors for laminin and fibronectin.
Lima
Osana C
OC
Departamento de Biologia Celular e Genética, Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro, UERJ, Rua São Francisco Xavier, 524-PHLC s/205, 20550-013, Rio de Janeiro, RJ, Brazil.
Bouchara
Jean-Philippe
JP
Renier
Gilles
G
Marot-Leblond
Agnes
A
Chabasse
Dominique
D
Lopes-Bezerra
Leila M
LM
D002448:Cell Adhesion; D005353:Fibronectins / Q000737:chemistry / Q000378:metabolism*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D007797:Laminin / Q000737:chemistry / Q000378:metabolism*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D011485:Protein Binding; D013175:Sporothrix / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology
D005353:Fibronectins; D007797:Laminin; D010455:Peptides