On-site secretory vesicle delivery drives filamentous growth in the fungal pathogen Candida albicans
Cellular Microbiology. e12963. First published: 15 October 2018
Allon Weiner1, François Orange2, Sandra Lacas‐Gervais2, Katya Rechav3, Vikram Ghugtyal1, Martine Bassilana1 & Robert A. Arkowitz1
1Université Côte d’Azur, CNRS, Inserm, Institute of Biology Valrose, Parc Valrose, Nice, France
2Université Côte d’Azur, CCMA, Parc Valrose, Nice, France
3Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
Candida albicans is an opportunistic fungal pathogen that colonises the skin as well as genital and intestinal mucosa of most healthy individuals. The ability of C. albicans to switch between different morphological states, for example, from an ellipsoid yeast form to a highly polarised, hyphal form, contributes to its success as a pathogen. In highly polarised tip‐growing cells such as neurons, pollen tubes, and filamentous fungi, delivery of membrane and cargo to the filament apex is achieved by long‐range delivery of secretory vesicles tethered to motors moving along cytoskeletal cables that extend towards the growing tip. To investigate whether such a mechanism is also critical for C. albicans filamentous growth, we studied the dynamics and organisation of the C. albicans secretory pathway using live cell imaging and three‐dimensional electron microscopy. We demonstrate that the secretory pathway is organised in distinct domains, including endoplasmic reticulum membrane sheets that extend along the length of the hyphal filament, a sub‐apical zone exhibiting distinct membrane structures and dynamics and a Spitzenkörper comprised of uniformly sized secretory vesicles. Our results indicate that the organisation of the secretory pathway in C. albicans likely facilitates short‐range “on‐site” secretory vesicle delivery, in contrast to filamentous fungi and many highly polarised cells.