Stehr F, Felk A, Kretschmar M, Schaller M, Schäfer W, Hube B (2000): Extracellular hydrolytic enzymes and their relevance during Candida albicans infections
Mycoses 43 (Supplement): 17-21.

Candida albicans can not only infect skin and mucosa, but also cause life threatening systemic candidosis. While natural barriers and the immunosystem of healthy individuals normally prevent such infections, virulence factors exist, that enable C. albicans to survive on surfaces and permits the fungus to invade tissue and organs in immunocompromised patients. Adhesion factors, morphological flexibility and hydrolytic enzymes belong to this group of factors. Equipped with a set of virulence attributes, the fungus must be able to use specific factors at distinct stages of an infection or for different types of candidosis. For example, distinct adhesion factors are important for the persistence on epithelial cells of mucosa, while other factors are necessary for the adhesion to endothelial tissue. This essential adaptation to different stages of an infection could be the reason that the fungus not only has single genes for extracellular hydrolytic enzymes, but gene families. Both secreted aspartate proteinases (Saps) and secreted lipases (Lips) from C. albicans are encoded by at least 10 different genes. This high number of similar genes may be a fundamental request to secrete an specific and optimised hydrolase at an distinct step of an infection. For both gene families a differential expression has been shown, which would be reasonable for such an adaptation. The expression studies revealed that distinct SAP and LIP genes are expressed even under conditions, when potential substrates (proteins or lipids) are not present in the growth medium. Such expression pattern are in agreement with the assumption, that these genes may have functions others than simply providing nutrients for the fungus. The specific transcription of single SAP genes during an course of infection implies that these genes have specific functions during a stage of an infection. In fact, inhibition studies and the use of mutants with targeted gene disruptions showed, that distinct SAP genes (SAP1-3) are important during infections of skin and mucosa, while others (SAP4-6) are more relevant for systemic infections.