A novel class of Candida glabrata cell wall proteins with β-helix fold mediates adhesion in clinical isolates

PLoS Pathog. 2021 Dec 28;17(12):e1009980. doi: 10.1371/journal.ppat.1009980. eCollection 2021 Dec.

Abstract

Candida glabrata is an opportunistic pathogenic yeast frequently causing infections in humans. Though it lacks typical virulence factors such as hyphal development, C. glabrata contains a remarkably large and diverse set of putative wall adhesins that is crucial for its success as pathogen. Here, we present an analysis of putative adhesins from the homology clusters V and VI. First, sequence similarity network analysis revealed relationships between cluster V and VI adhesins and S. cerevisiae haze protective factors (Hpf). Crystal structures of A-regions from cluster VI adhesins Awp1 and Awp3b reveal a parallel right-handed β-helix domain that is linked to a C-terminal β-sandwich. Structure solution of the A-region of Awp3b via single wavelength anomalous diffraction phasing revealed the largest known lanthanide cluster with 21 Gd3+ ions. Awp1-A and Awp3b-A show structural similarity to pectate lyases but binding to neither carbohydrates nor Ca2+ was observed. Phenotypic analysis of awp1Δ, awp3Δ, and awp1,3Δ double mutants did also not confirm their role as adhesins. In contrast, deletion mutants of the cluster V adhesin Awp2 in the hyperadhesive clinical isolate PEU382 demonstrated its importance for adhesion to polystyrene or glass, biofilm formation, cell aggregation and other cell surface-related phenotypes. Together with cluster III and VII adhesins our study shows that C. glabrata CBS138 can rely on a set of 42 Awp1-related adhesins with β-helix/α-crystallin domain architecture for modifying the surface characteristics of its cell wall.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biofilms / growth & development
  • Candida glabrata / genetics*
  • Candida glabrata / metabolism
  • Candida glabrata / pathogenicity
  • Candidiasis / microbiology*
  • Cell Adhesion
  • Cell Adhesion Molecules / chemistry
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / metabolism
  • Cell Wall / metabolism
  • Fungal Proteins / chemistry*
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Humans
  • Models, Molecular
  • Virulence Factors

Substances

  • Cell Adhesion Molecules
  • Fungal Proteins
  • Virulence Factors

Grants and funding

LOE and VR received funding from Deutsche Forschungsgemeinschaft [SFB 987]. PdG, JFP and MA received funding from the Spanish Ministry of Economy and Competitiveness (MINECO) [SAF2013-47570-P and SAF2017-86188-P], and the Regional government of Castilla-La Mancha [SBPLY/19/180501/000114 and SBPLY/19/180501/000356], the Spanish grants co-financed by the EU (FEDER). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.