The Cbp1 protein is a peptidorhamnomannan adhesin that contributes to the Sporothrix schenckii virulence

Abstract

Sporothrix schenckii pathogenesis has been extensively studied to date, but several proteins of unknown function remain to be assigned to the infectious process. Previously, proteomic data showed that one protein was highly abundant (SPSK_02764) in cell wall peptidorhamnomannan, but no obvious homologs or sequence features hinted at the activity or function of this protein. In this work, in vitro analysis showed that this protein is highly glycosylated and is an adhesin with specificity for type-I and type-II collagen, renaming this protein as Collagen Binding Protein 1 or Cbp1. Yeast-like cells preincubated with anti-SPSK_02764 antibody reduced the ability to kill Galleria mellonella larvae and to induce immune effectors, suggesting a role for this protein in S. schenckii pathogenesis. Bioinformatic analysis suggested that the protein may be a moonlighting protein that is broadly present in Ascomycota and is sequence and structurally conserved. The findings shown here suggest that Cbp1 is another component of the S. schenckii cell wall and participates in host collagen binding, adding a new component to the pathogenesis toolbox of this organism.