Vesicular transport across the fungal cell wall
In eukaryotes, cell walls are found in many plant, fungal and algal species. The fungal cell wall is located outside the cell membrane and serves a protective function by providing rigidity, mechanical strength and shielding of the protoplast from the environment. Fungal cell walls are composed of a tight, semipermeable fibrous network of polymers such as chitin, glucan polysaccharides and mannoproteins. Most human pathogenic fungi have cell walls, which are important targets for antifungal drug discovery. The importance of the cell wall for fungal cell survival is evident by the fact that antifungal drugs that disrupt cell wall biosynthesis are fungicidal. The ability of the cell wall to protect the cell by limiting access to outside molecules also provides a potential barrier to diffusion of fungal products. Fungi in the environment obtain their food by digesting organic matter in their environment with enzymatic cocktails that produce small molecules that are then absorbed. Consequently, fungal cells must have efficient mechanisms for the transport and export of cellular products required for nutrient acquisition.
Vesicular transport across the fungal cell wall. Trends Microbiol. 2009 17(4): 158-162
Recent findings indicate that fungi use vesicular transport to deliver substances across their cell walls. Fungal vesicles are similar to mammalian exosomes and could originate from cytoplasmic multivesicular bodies. Vesicular transport enables the export of large molecules across the cell wall, and vesicles contain lipids, proteins and polysaccharides, many of which are associated with virulence. Concentration of fungal products in vesicles could increase their efficiency in food acquisition and/or delivering potentially noxious substances to other cells, such as amoebae or phagocytes. The discovery of vesicular transport in fungi opens many new avenues for investigation in basic cell biology and pathogenesis.
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Tags: Biology, cell wall, Drugs, Fungi, Microbiology, Mycology, polymers, Science, vesicles
