Abstract
Members of the Cysteine-rich secretory protein, Antigen 5 and Pathogenesis-related 1 (CAP) protein superfamily are important virulence factors in fungi but remain poorly characterized on molecular level. Here, we investigate the cellular localization and molecular function of Rbe1p and Rbt4p, two CAP family members from the human pathogen Candida albicans. We unexpectedly found that Rbe1p localizes to budding sites of yeast cells in a disulfide bond-dependent manner. Furthermore, we show that Rbe1p and Rbt4p bind free cholesterol in vitro and export cholesteryl acetate in vivo. These findings suggest a previously undescribed role for Rbe1p in cell wall-associated processes and a possible connection between the virulence attributes of fungal CAP proteins and sterol binding.
Highlights
Quantification of export rates revealed that expression of RBE1 or RBT4 resulted in a significantly higher export index compared to the pry1Δ pry2Δ mutant, indicating that lipid export might be a conserved function of fungal CAP proteins (Fig 2D)
Members of the CAP protein superfamily have emerged as novel virulence factors in fungi, but remain a poorly characterized class of proteins [31, 32]
Our analysis revealed that Rbe1p can be attached to the yeast cell wall via disulfide bonds, while Rbt4p is constitutively secreted under the experimental conditions used
Summary
Data Availability Statement: All relevant data are within the paper and its Supporting Information files. CAP family members are associated with diverse biological processes, including immune defense, venom toxicity, reproduction and cancer development [1]. Despite their functional and evolutionary diversity, their molecular mode of action remains largely elusive. The human fungal pathogen Candida albicans encodes five CAP proteins and two of them, Rbe1p and Rbt4p, have been shown to be important virulence factors [3,4,5]. Finding the link between the virulence phenotype and the molecular function of Rbe1p and Rbt4p has remained a challenge, especially because no functional or structural data on protein level is available yet. We link Rbe1p and Rbt4p function to sterol binding and export
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
