Abstract
The fungal plasma membrane is critical for cell wall synthesis and other important processes including nutrient uptake, secretion, endocytosis, morphogenesis, and response to stress. To coordinate these diverse functions, the plasma membrane is organized into specialized compartments that vary in size, stability, and composition. One recently identified domain known as the Membrane Compartment of Can1 (MCC)/eisosome is distinctive in that it corresponds to a furrow-like invagination in the plasma membrane. MCC/eisosomes have been shown to be formed by the Bin/Amphiphysin/Rvs (BAR) domain proteins Lsp1 and Pil1 in a range of fungi. MCC/eisosome domains influence multiple cellular functions; but a very pronounced defect in cell wall synthesis has been observed for mutants with defects in MCC/eisosomes in some yeast species. For example, Candida albicans MCC/eisosome mutants display abnormal spatial regulation of cell wall synthesis, including large invaginations and altered chemical composition of the walls. Recent studies indicate that MCC/eisosomes affect cell wall synthesis in part by regulating the levels of the key regulatory lipid phosphatidylinositol 4,5-bisphosphate (PI4,5P2) in the plasma membrane. One general way MCC/eisosomes function is by acting as protected islands in the plasma membrane, since these domains are very stable. They also act as scaffolds to recruit >20 proteins. Genetic studies aimed at defining the function of the MCC/eisosome proteins have identified important roles in resistance to stress, such as resistance to oxidative stress mediated by the flavodoxin-like proteins Pst1, Pst2, Pst3 and Ycp4. Thus, MCC/eisosomes play multiple roles in plasma membrane organization that protect fungal cells from the environment.
Highlights
The plasma membrane has a complex mission to form a protective barrier around the cell while mediating a wide range of dynamic functions
C. albicans Sur7 has been shown to be recruited to sites of neutrophil attack, suggesting a role for Membrane Compartment of Can1 (MCC)/eisosomes in the new cell wall synthesis that occurs in response to this type of cell wall damage [78]
Eisosomes have been shown to play a role in surviving hypo-osmotic stress in S. pombe protoplasts [23]. These results indicate that MCC/eisosomes are important for maintaining cell wall strength, future studies will be needed to determine if this role is direct or indirect since sites of cell wall synthesis do not appear to overlap with eisosomes
Summary
The plasma membrane has a complex mission to form a protective barrier around the cell while mediating a wide range of dynamic functions. As will be described in more detail below, Pil and Lsp promote MCC/eisosome formation by binding the plasma membrane through their BAR (Bin/Amphiphysin/Rvs) domains and assembling into long filaments to stabilize these structures [39]. This cluster of proteins was termed the eisosome, a fusion of the Greek “eis”, meaning into or portal, and “soma”, meaning body, as these patchy domains were initially thought to correspond to sites of endocytosis [12].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
