Study On The Functions Of CaCDC50 In Candida Albicans

Candida albicans was the most common opportunistic fungal pathogen of humans,and it was also leading of conditional pathogenic fungus in clinic.The flippase also known as phospholipid translocator,it translocates phosphatidylserine?PS?and/or phosphatidylethanolamine?PE?from one leaflet of the bilayer to the other and establishes phospholipid asymmetry in membranes and functions in vesicle-mediated trafficking in Saccharomyces cerevisiae.Cdc50 was the non-catalytic subunit of the flippase,and ScCDC50 plays an important role in S.cerevisiae.Here,we have identified the homologous gene CaCDC50.At present,the function of CaCDC50 is unknow.In this study,we constructed a null mutant for CaCDC50 by homologous recombination method.The effects of CaCDC50 on the antifungal drug sensitivity,cationic tolerance and cell wall integrity of C.albicans were studied by drug pressure phenotype test and cell wall composition test.Fluorescence staining test and virulence test were used to study the effects of CaCDC50 deficiency on the vacuole morphology,hyphae development and virulence of C.albicans.We find the phenotype of ScCDC50 deletion strain of S.cerevisiae was supplemented by CaCDC50.Deletion of CaCDC50 results in C.albicans cells becoming sensitive to the antifungal drugs azoles,terbinafine and caspofungin,as well as to the membrane-perturbing agent sodium dodecyl sulfate,congo red and fluorescent brightener.We also show that the contents of glucan and chitin were increased,and the phosphomannan content was markedly reduced in the cell wall of Cacdc50/Cacdc50 mutant.In addition,the phosphorylation level of Mkc1 and Cek1 increased in the Cacdc50/Cacdc50 mutant.CaCDC50 confers tolerance to high concentrations of cations that including Zn²⁺?Cu²⁺?Cd²⁺?Co²⁺and Li⁺.We also found out the absence of CaCDC50 resulted in the abnormality of vacuole morphology and the change of budding site of C.albicans.Moreover,deletion of CaCDC50 leads to severe defects in hyphal development of C.albicans cells.Furthermore,deletion of CaCDC50 led to a decrease in the ability of C.albicans cells to infect the kidneys of mice,and the lethality of mice decreased.Therefore,CaCDC50 plays an important role in the tolerance of C.albicans to antifungal drugs,cell wall integrity,vacuole morphology,mycelial development and virulence.