Biosynthesis and Genetics of the Cryptococcus Capsule

摘要: Until the late 1940s, little was known about cryptococcal capsule composition or structure. Classically, is described as composed of glucuronoxylomannan (GXM), galactoxylomannan (GalXM), and mannoproteins, based on original fractionation shed polysaccharide material. Cell wall polymers are involved in association with cell, although they not considered part itself. Polysaccharide synthesis starts generation precursor molecules, most common being activated sugars discovered by Leloir. A number proteins these precursors have been identified studied Cryptococcus neoformans. This work has facilitated fact that many enzymes highly conserved terms sequence, would be expected from participation sugar multiple synthetic pathways across biology. In support a lumenal location for synthesis, conditional mutant generated both serotypes D defective vesicle targeting to plasma membrane accumulates post-Golgi vesicles containing GXM. The conclusion this study GXM made within classical secretory pathway, consistent requirement nucleotide transporters achieve normal synthesis.