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Updated: Aug 15, 2026
Visualization of Candida albicans in the Murine Gastrointestinal Tract Using Fluorescent In Situ Hybridization
Published on: November 5, 2019
Intracellular trafficking of fluorescently tagged proteins associated with pathogenesis in Candida albicans
Samuel A Lee1, Zachary Khalique, Cheryl A Gale
1Infectious Diseases Section, Yale University School of Medicine, New Haven, Connecticut, USA.
Abstract:
Proteins that enter the secretory pathway play important roles in virulence and pathogenesis in Candida albicans, but our understanding of the trafficking of these proteins is in its early stages. In Saccharomyces cerevisiae, dominant negative alleles of YPT1 and SEC4 interrupt secretory traffic at pre- and post-Golgi steps, respectively. We therefore used a dominant negative genetic approach to examine the intracellular trafficking of several proteins associated with virulence or azole resistance. When the dominant negative ypt1(N121I) allele of C. albicans was overexpressed, yellow-fluorescent protein (YFP) tagged forms of two plasma membrane transporters (Cdrlp and Ftrlp) and the vacuolar membrane ABC transporter Mltlp accumulated in intracellular structures that appeared related to the ER, but localization of Cdc10p and Int1p was unaffected. When the dominant negative sec4(S28N) allele of C. albicans was overexpressed, Cdrlp and Ftrlp accumulated intracellularly, and localization of Mltlp, Cdc10p and Int1p was unaffected. These results imply that (i) Cdrlp and Ftrlp are transported to the plasma membrane by the general secretory pathway, (ii) Mlt1p enters the secretory pathway but is diverted to the vacuole at an early post-Golgi step, and (iii) like Cdc10p, Int1p does not enter the general secretory pathway.
Insights
Investigating protein trafficking in Candida albicans reveals that Cdrlp and Ftrlp use the general secretory pathway, while Mltlp is diverted to the vacuole. Some proteins do not enter this pathway.
Area of Science:
- Cell Biology
- Mycology
- Molecular Biology
Background:
- Proteins in the secretory pathway are crucial for Candida albicans virulence and pathogenesis.
- Understanding protein trafficking in C. albicans is essential but remains limited.
Purpose of the Study:
- To investigate the intracellular trafficking of virulence-associated and azole resistance proteins in Candida albicans.
- To utilize a dominant-negative genetic approach to elucidate secretory pathway dynamics.
Main Methods:
- Overexpression of dominant-negative alleles ypt1(N121I) and sec4(S28N) in Candida albicans.
- Localization studies of yellow-fluorescent protein (YFP)-tagged transporters (Cdrlp, Ftrlp, Mltlp) and proteins (Cdc10p, Int1p).
Main Results:
- Overexpression of ypt1(N121I) caused accumulation of Cdrlp, Ftrlp, and Mltlp in ER-associated structures, leaving Cdc10p and Int1p unaffected.
- Overexpression of sec4(S28N) resulted in intracellular accumulation of Cdrlp and Ftrlp, with unaffected localization of Mltlp, Cdc10p, and Int1p.
- Differential protein localization suggests distinct trafficking routes.
Conclusions:
- Cdrlp and Ftrlp utilize the general secretory pathway for transport to the plasma membrane.
- Mltlp enters the secretory pathway but is rerouted to the vacuole post-Golgi.
- Cdc10p and Int1p do not appear to enter the general secretory pathway in C. albicans.
