Identification of the cell-surface lectin domain-containing protein expressed in the adhesive colony morphology of Trichosporon asahii.

Abstract

Trichosporon asahii is a yeast pathogen that causes a deep-seated infection. In fungal infections, molecules involved in adhesion to host tissues or catheters are one of the pathogenic factors. A single strain of T. asahii produces various colony morphologies, including highly adhesive colony types, but the molecules involved in the adhesiveness have not been identified. This study compared proteins in cell-surface extracts from weakly and highly adherent colony types and identified a protein abundantly expressed in highly adherent cells, which was named T. asahii R-type lectin domain-containing protein (TAL). TAL was a predicted 48 kDa protein with a carbohydrate-binding region, but a band was detected at ∼250 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting that it was highly glycosylated. When TAL was overexpressed in mammalian cells and deglycosylated, the protein size decreased, confirming that it was glycosylated. In weakly adherent colony-type cells, the bands detected by anti-TAL antiserum were barely noted. The absence of bands indicates that the protein expression was low and does not suggest that the degree of glycosylation was different. These results suggested that multiple colony types derived from a single strain have different pathogenic properties.