The commensal and pathogenic lifestyles of the opportunistic fungal pathogen Candida albicans require complex signalling networks regulated by protein kinases. To investigate the role of C. albicans protein kinases at the intestinal epithelial interface, we screened a comprehensive protein kinase deletion library for the capacity of the mutants to damage intestinal epithelial cells (IEC). Mutants showing altered IEC cytotoxicity relative to the wild type were further analysed for their growth and morphology, focusing on hyper-damaging strains to identify kinases that rather prevent host cell damage. Deletion of CRK1 caused increased IEC-specific damage, despite slower growth, reduced hyphal length, and reduced adhesion as compared to wild-type cells. While tissue invasion levels and the formation of trans-cellular tunnels of the crk1Δ/Δ mutant were increased, the translocation capacity through the IEC barrier was reduced. Transcriptional and metabolic profiling suggested a role for Crk1 in metabolic adaptation to carbon and nitrogen sources, which was validated by showing that high glucose and amino acids are required for crk1Δ/Δ to cause increased IEC damage. Deletion of CRK1 rendered C. albicans more susceptible to cell wall and membrane stressors but caused higher resistance to a catalase-specific and histidine biosynthesis inhibitor. This phenotypic pattern of medium- and epithelial cell type-specific cytotoxicity displayed by a C. albicans protein kinase mutant suggests that Crk1 regulates processes linked to carbon and amino acid metabolism that are relevant to interactions with intestinal epithelial cells.
2026-07-24
Functional analysis of Candida albicans protein kinases identifies Crk1 as a modulator of epithelial cell damage
Anna Möslinger , Dr. Allon Weiner , Sascha Schäuble , Dr. Bernardo Ramírez-Zavala , Nadja Jablonowski , Zoltán Cseresnyés , Tim Bastian Schille , Prof. Marc Thilo Figge , Prof. Gianni Panagiotou , Dr. Joachim Morschhäuser , Dr. Lydia Kasper , Mark Gresnigt , Ms. Stefanie Allert , Prof. Bernhard Hube (corr-auth)
mBio