Characterization and functional analysis of ERAD-related AAA+ ATPase Cdc48 in Aspergillus oryzae

Yuki Morita, Futa Kikumatsu, Yujiro Higuchi, Yoshinori Katakura, Kaoru Takegawa

Research output: Contribution to journalArticle

Abstract

Aspergillus oryzae can secrete large amounts of enzymes. However, the production of abundant secretory proteins triggers the unfolded protein response (UPR) in the endoplasmic reticulum (ER), and it is not clear how ER-associated protein degradation (ERAD) contributes to bulk protein production in A. oryzae. Here we identified AoCdc48, the sole A. oryzae ortholog of Saccharomyces cerevisiae AAA+ ATPase Cdc48, a component of the ERAD machinery. We found that AoCdc48 localizes in both nuclei and cytoplasm. Generation of an Aocdc48 conditional mutant showed that Aocdc48 repression leads to reduced cell growth and aberrant hyphal morphology. When Aocdc48-repressed cells were cultured on starch-containing plates, the α-amylase-encoding gene amyB was about 1.3-fold higher expressed. Indeed, a halo produced by secreted amylase was seen on potato starch-containing plates even when there was almost no growth under Aocdc48 repression. Fluorescence microscopy revealed that although AmyB seemed to be secreted, various organelle distributions were aberrant in Aocdc48-repressed cells. We found that D1 AAA domain is crucial for cell viability. Finally, we show that Aocdc48-overexpression also causes defects of cell growth, colonial morphology and conidial formation. Collectively, our results suggest that AoCdc48 is essential for growth and organelle distribution but dispensable for amylase secretion.

Original languageEnglish
Pages (from-to)801-813
Number of pages13
JournalFungal Biology
Volume124
Issue number9
DOIs
Publication statusPublished - Sep 2020

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Infectious Diseases

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