The synthesis of foldases and chaperones, which are resident in the lumen of the endoplasmic reticulum (ER) and assist the folding of secretory proteins, is regulated at the transcriptional level by the unfolded protein response (UPR). We have shown that perturbation of the protein folding process in Aspergillus niger, whether by chemicals such as tunicamycin, dithiothreitol and a calcium ionophore or by the secretion of heterologous proteins, leads to up-regulation.of the synthesis of foldases such as protein disulphide isomerase (PDI encoded by pdiA). We have also shown that, under the conditions of UPR, the transcription of the gene encoding acetyl-CoA carboxylase (ACC encoded by accA in A.nidulans), is up-regulated. ACC catalyses the first committed step in membrane fatty acid synthesis, suggesting that UPR coordinates the synthesis of ER membrane with the synthesis of ER lumenal proteins. UPR may have even wider regulatory roles which will also be presented.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)