Sensing the host environment: recognition of hemoglobin by the pathogenic yeast Candida albicans.
Adhesion to host cells and tissues is important for several steps in the pathogenesis of disseminated Candida albicans infections. Although such adhesion is evident in vivo and for C. albicans grown in vitro in complex medium, some adhesive activities are absent when cultures are grown in defined media. However, addition of hemoglobin to defined media restores binding and adhesion to several host proteins. This activity of hemoglobin is independent of iron acquisition and is mediated by a cell surface hemoglobin receptor. In addition to regulating expression of adhesion receptors, hemoglobin rapidly induces expression of several genes. One of these, a heme oxygenase, allows the pathogen to utilize exogenous heme or hemoglobin to acquire iron and to produce the cytoprotective molecules alpha-biliverdin and carbon monoxide. The specific recognition of and responses to hemoglobin demonstrate a unique adaptation of C. albicans to be both a commensal and an opportunistic pathogen in humans.
Pendrak
Michael L
ML
Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1500, USA.
Yan
S Steve
SS
Roberts
David D
DD
D001665:Binding Sites; D002176:Candida albicans / Q000187:drug effects* / Q000502:physiology*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism*; D022001:Focal Adhesions / Q000187:drug effects / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism* / Q000494:pharmacology*; D011485:Protein Binding
D005353:Fibronectins; D006454:Hemoglobins; D006419:Heme Oxygenase (Decyclizing)