Mutation in a calpain-like protease affects the posttranslational mannosylation of phosphatases in Aspergillus nidulans

In this communication, we show that the palB7 mutation drastically reduced the mannose and N-acetylgalactosamine content f the pacA-encoded acid phosphatase secreted by the fungus Aspergillus nidulans at pH 5.0, compared to a control strain. y using mRNA differential display reverse transcription and polymerase chain reaction, we isolated two cDNAs from the ontrol pabaA1 strain that were not detected in the palB7 mutant strain that encode a mannosyl transferase and a NADHbiquinone oxidoreductase. Thus, a defect in the posttranslational mannosylation of proteins could be the consequence of utations in the palB gene, which encodes for a nuclear calpain-like protease that may have specific functions in the processing f transcription factor(s) similar to its homolog, RIM13, in Saccharomyces cereviseae.