Sth1, the ATPase subunit of the RSC chromatin remodeler has important roles in stress response and DNA damage repair in the pathogenic fungi Candida albicans

Morphogenic plasticity: the pathogenic attribute of Candida albicans

Candida albicans is a commensal organism of the human gastrointestinal tract and a prevalent opportunistic pathogen. It exhibits different morphogenic forms to survive in different host niches with distinct environmental conditions (pH, temperature, oxidative stress, nutrients, serum, chemicals, radiation, etc.) and genetic factors (transcription factors and genes). The different morphogenic forms of C. albicans are yeast, hyphal, pseudohyphal, white, opaque, and transient gray cells, planktonic and biofilm forms of cells. These forms differ in the parameters like cellular phenotype, colony morphology, adhesion to solid surfaces, gene expression profile, and the virulent traits. Each form is functionally distinct and responds discretely to the host immune system and antifungal drugs. Hence, morphogenic plasticity is the key to virulence. In this review, we address the characteristics, the pathogenic potential of the different morphogenic forms and the conditions required for morphogenic transitions.

Functional analysis of the RSC9 component of RSC chromatin remodeler reveals non-overlapping roles among the different subunits in C. albicans

RSC (Remodel the Structure of Chromatin) chromatin remodeler in S. cerevisiae has multiple subunits, some of them are essential whereas the others are non-essential for cell viability. Not all the subunits are involved in all the functions of RSC complex. With several lines of evidences showing somewhat similar role of RSC complex [through Sth1 (Snf Two Homolog 1)] in different aspects of cell cycle (chromosome segregation and kinetochore function, etc.), DNA damage repair and stress response in C. albicans and S. cerevisiae, we hypothesize the organization of RSC complex in C. albicans could follow the same pattern as observed in S. cerevisiae. We hypothesize that the subset of the subunits could form different subcomplexes to do different biological functions where several subunits are common among the subcomplexes. We wished to address if the accessory component Rsc9 protein of RSC complex has any non-overlapping function with respect to the ATPase component Sth1 of the RSC complex in C. albicans. Here, we have shown that the rsc9 mutant exhibit abnormal nuclear segregation, though budding profile is comparable to the wild type. Rsc9 does not affect yeast to hyphae transition. Though both Sth1 and Rsc9 belong to the same RSC complex, individual protein is functionally distinct, and the respective mutant shows different phenotype and different consequence in cellular process. This suggests that though RSC works as a single complex having global remodeling activity, different subunit can form distinct modules which show functional disparity, as the components show some similar and some distinct function.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03341-w.