The ZIP family zinc transporters support the virulence of Cryptococcus neoformans.
Zinc is an essential element in living organisms and a cofactor for various metalloproteins. To disseminate and survive, a pathogenic microbe must obtain zinc from the host, which is an environment with extremely limited zinc availability. In this study, we investigated the roles of the ZIP family zinc transporters Zip1 and Zip2 in the human pathogenic fungus Cryptococcus neoformans Zip1 and Zip2 are homologous to Zrt1 and Zrt2 of the model fungus, Saccharomyces cerevisiae, respectively. We found that the expression of ZIP1 was regulated by the zinc concentration in the environment. Furthermore, the mutant lacking ZIP1 displayed a severe growth defect under zinc-limited conditions, while the mutant lacking ZIP2 displayed normal growth. Inductively coupled plasma-atomic emission spectroscopy analysis showed that the absence of Zip1 expression significantly reduced total cellular zinc levels relative to that in the wild type, while overexpression of Zip1 was associated with increased cellular zinc levels. These findings suggested that Zip1 plays roles in zinc uptake in C. neoformans We also constructed a Zip1-FLAG fusion protein and found, by immunofluorescence, not only that the protein was localized to the periphery implying it is a membrane transporter, but also that the protein was N-glycosylated. Furthermore, the mutant lacking ZIP1 showed attenuated virulence in a murine inhalation model of cryptococcosis and reduced survival within murine macrophages. Overall, our data suggest that Zip1 plays essential roles in zinc transport and the virulence of C. neoformans.
Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea.
Eunsoo
E
Do
The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver BC, V6T 1Z4, Canada.
Guanggan
G
Hu
The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver BC, V6T 1Z4, Canada.
Mélissa
M
Caza
The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver BC, V6T 1Z4, Canada.
James W
JW
Kronstad
Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea whjung@cau.ac.kr.
Won Hee
WH
Jung
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D003453:Cryptococcosis / Q000382:microbiology / Q000473:pathology; D003455:Cryptococcus neoformans / Q000254:growth & development* / Q000472:pathogenicity*; D005260:Female; D020869:Gene Expression Profiling; D055786:Gene Knockout Techniques; D008807:Mice, Inbred BALB C; D014774:Virulence; D037521:Virulence Factors / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
D002352:Carrier Proteins; D037521:Virulence Factors; C017800:zinc-binding protein; D015032:Zinc
Cryptococcus neoformans; Fungi; Metal; Virulence; Zinc