The cell wall: a carbohydrate armour for the fungal cell

Abstract

SummaryThe cell wall is composed of a polysaccharide-based three-dimensional network. Considered for a long time as an inert exoskeleton, the cell wall is now seen as a dynamic structure that is continuously changing as a result of the modification of culture conditions and environmental stresses. Although the cell wall composition varies among fungal species, chemogenomic comparative analysis have led to a better understanding of the genes and mechanisms involved in the construction of the common central core composed of branched b1,3 glucan-chitin. Because of its essential biological role, unique biochemistry and structural organization and the absence in mammalian cells of most of its constitutive components, the cell wall is an attractive target for the development of new antifungal agents. Genomic as well as drug studies have shown that the death of the fungus can result from inhibition of cell wall polysaccharide synthases. To date, only b1,3 glucan synthase inhibitors have been launched clinically and many more targets remain to be explored.

Enzyme secretion by ECM fungi and exploitation of mineral nutrients from soil organic matter

“…Fungal enzymes aimed at being secreted are synthesised at ribosomes, glycosilated in the endoplasmatic reticulum, eventually modified during transport in Golgi vesicles and finally transported to the plasmalemma where they leave the cell interior. Besides the classical way, alternatives of enzyme secretion are also reported (Latgé 2007). Irrespective of the secretion system, once transported to the outside of the cell, enzymes are either released as free enzymes or are bound in different ways at the outside.…”

Lectin mapping reveals stage-specific display of surface carbohydrates in in vitro and haemolymph-derived cells of the entomopathogenic fungus Beauveria bassiana

“…Although this is speculative, this structure may mask the hyphal bodies from the host immune system, allowing for the free circulation of these cells. Surface fibrillar structures, either proteinaceous or carbohydrate in nature, some of which are thought to contribute to virulence and immune evasion, have long been noted on yeasts and A. Wanchoo, M. W. Lewis and N. O. Keyhani other fungi (Hazen & Hazen, 1993;Latgé et al, 1988;Latgé, 2007;Osumi, 1998;Takeo et al, 1993;Teertstra et al, 2009). Further characterization of the composition and potential role of the B. bassiana material is warranted.…”

Comparative proteomic analysis of an Aspergillus fumigatus mutant deficient in glucosidase I (AfCwh41)

“…The A. fumigatus cell wall provides both protective and aggressive functions, and thus has been recognized for a long time as an essential and unique specific drug target. The cell wall mainly consists of a covalently connected polysaccharide skeleton interlaced and coated with glycoproteins and GPI (glycosylphosphatidylinositol) proteins, which contain N-and O-glycans derived primarily from the process of glycosylation (Latgé, 2007). Although these glycoproteins are involved in morphogenesis and cell wall organization (Mouyna et al, 2000(Mouyna et al, , 2005Bruneau et al, 2001;Chabane et al, 2006;Romano et al, 2006;de Groot et al, 2005;Li et al, 2007), it is poorly understood how glycosylation affects the cell wall organization.…”