Phenotypic analysis of α1,2-mannosidase-like protein deletion mutants in Saccharomyces cerevisiae.

α1,2­mannosidase-like proteins mediate quality control of glycoproteins in the endoplasmic reticulum. This study explored α1,2­mannosidase-like protein functions in Saccharomyces cerevisiae. Single disruptants in targeted protein-coding genes were found to be viable; however, deletion of MNL2 resulted in declined yeast growth at 37 °C. The normal growth rate was recovered in double-deletion strains where one of the deletions was in MNS1 . We also measured the mannosidase activity of microsomal fractions of deficient strains using artificial glycan. Increased mannose trimming activities were demonstrated by the microsomes of MNL2 -deletion strains compared to levels of activity exhibited by the microsomes of the control strain.