@article{mbs:/content/journal/micro/10.1099/mic.0.2008/019315-0, author = "Mora-Montes, Héctor M. and Bader, Oliver and López-Romero, Everardo and Zinker, Samuel and Ponce-Noyola, Patricia and Hube, Bernhard and Gow, Neil A. R. and Flores-Carreón, Arturo", title = "Kex2 protease converts the endoplasmic reticulum α1,2-mannosidase of Candida albicans into a soluble cytosolic form", journal= "Microbiology", year = "2008", volume = "154", number = "12", pages = "3782-3794", doi = "https://doi.org/10.1099/mic.0.2008/019315-0", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.2008/019315-0", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "CPY, carboxypeptidase Y", keywords = "ER, endoplasmic reticulum", keywords = "1-DMJ, 1-deoxymannojirimycin", keywords = "MUαMan, 4-methylumbelliferyl-α-d-mannopyranoside", keywords = "M7B, Man7GlcNAc2 isomer B", keywords = "MU, 4-methylumbelliferone", keywords = "ERAD, endoplasmic-reticulum-associated degradation", keywords = "AEBSF, 4-(2-aminoethyl)benzenesulfonyl fluoride", keywords = "M9, Man9GlcNAc2", keywords = "E64, trans-epoxysuccinyl-l-leucyl-amido(4-guanidino)butane", keywords = "M8B, Man8GlcNAc2 isomer B", abstract = "Cytosolic α-mannosidases are glycosyl hydrolases that participate in the catabolism of cytosolic free N-oligosaccharides. Two soluble α-mannosidases (E-I and E-II) belonging to glycosyl hydrolases family 47 have been described in Candida albicans. We demonstrate that addition of pepstatin A during the preparation of cell homogenates enriched α-mannosidase E-I at the expense of E-II, indicating that the latter is generated by proteolysis during cell disruption. E-I corresponded to a polypeptide of 52 kDa that was associated with mannosidase activity and was recognized by an anti-α1,2-mannosidase antibody. The N-mannan core trimming properties of the purified enzyme E-I were consistent with its classification as a family 47 α1,2-mannosidase. Differential density-gradient centrifugation of homogenates revealed that α1,2-mannosidase E-I was localized to the cytosolic fraction and Golgi-derived vesicles, and that a 65 kDa membrane-bound α1,2-mannosidase was present in endoplasmic reticulum and Golgi-derived vesicles. Distribution of α-mannosidase activity in a kex2Δ null mutant or in wild-type protoplasts treated with monensin demonstrated that the membrane-bound α1,2-mannosidase is processed by Kex2 protease into E-I, recognizing an atypical cleavage site of the precursor. Analysis of cytosolic free N-oligosaccharides revealed that cytosolic α1,2-mannosidase E-I trims free Man8GlcNAc2 isomer B into Man7GlcNAc2 isomer B. This is believed to be the first report demonstrating the presence of soluble α1,2-mannosidase from the glycosyl hydrolases family 47 in a cytosolic compartment of the cell.", }