A fungal arrestin protein contributes to cell cycle progression and pathogenesis

Abstract

word count: 231 19 Text word count: 5,955 20 2 ABSTRACT 21 Arrestins, a structurally specialized and functionally diverse group of proteins, are 22 central regulators of adaptive cellular responses in eukaryotes. Previous studies on 23 fungal arrestins have demonstrated their capacity to modulate diverse cellular 24 processes through their adaptor functions, facilitating the localization and function of 25 other proteins. However, the mechanisms by which arrestin-regulated processes are 26involved in fungal virulence remain unexplored. We have identified a small family of four 27 arrestins -Ali1, Ali2, Ali3, and Ali4 -in the human fungal pathogen Cryptococcus 28 neoformans. Using complementary microscopy, proteomic, and reverse genetic 29 techniques, we have defined a role for Ali1 as a novel contributor to cytokinesis, a 30 fundamental cell cycle-associated process. We observed that Ali1 strongly interacts with 31 proteins involved in lipid synthesis, and that ali1 mutant phenotypes are rescued by 32 supplementation with lipid precursors that are used to build cellular membranes. From 33 these data, we hypothesize that Ali1 contributes to cytokinesis by serving as an adaptor 34 protein, facilitating the localization of enzymes that modify the plasma membrane during 35 cell division, specifically the fatty acid synthases, Fas1 and Fas2. Finally, we assessed 36 the contributions of the C. neoformans arrestin family to virulence, to better understand 37 the mechanisms by which arrestin-regulated adaptive cellular responses influence 38 fungal infection. We observed that the C. neoformans arrestin family contributes to 39 virulence, and that the individual arrestin proteins likely fulfill distinct functions that are 40 important for disease progression. 41 3 IMPORTANCE 42 To survive in unpredictable conditions, all organisms must adapt to stressors by 43 regulating adaptive cellular responses. Arrestin proteins are conserved regulators of 44 adaptive cellular responses in eukaryotes. Studies that have been limited to mammals 45 and model fungi have demonstrated that disruption of arrestin-regulated pathways is 46 detrimental for viability. The human fungal pathogen Cryptococcus neoformans causes 47 56

Lessons on fruiting body morphogenesis from genomes and transcriptomes of Agaricomycetes

“…Finally, we detected two arrestin superfamily orthogroups ( C. cinerea protein ID: 473465, S. commune: Schco3_2490312) (Table 18). Arrestins are involved in signal transduction through the inactivation of G protein-coupled receptors, but some members of the superfamily have been reported in receptor endocytosis, cell cycle progression and pH sensing as well also(Herranz et al 2005; Telzrow et al 2019).…”

Sterol-response pathways mediate alkaline survival in diverse fungi

“…J774A.1 cells were incubated in a humidified 37°C incubator with 5% CO 2 , passaged twice weekly, and were kept in tissue culture flasks in 20-25 ml of macrophage medium (DMEM, heat-inactivated fetal bovine serum-FBS, Penicillin-streptomycin (Gibco 15140-122), and MEM non-essential amino acid solution (Gibco 11140-050)). Survival of C. neoformans strains within alveolar macrophage-like J744A.1 cells was assessed by aliquoting 100 μl of 10 5 viable cells into a 96-well plate, avoiding edges as previously described (83). The plates were incubated overnight in 37°C incubator with 5% CO 2 .…”