Stress effects caused by the expression of a mutant cellobiohydrolase I and proteasome inhibition in trichoderma reesei rut-C30

Kautto, Liisa and Grinyer, Jasmine and Paulsen, Ian and Tetu, Sasha and Pillai, Aneesh and Pardiwalla, Swapneel and Sezerman, Uğur and Bayram Akçapınar, Günseli and Bergquist, Peter and Te'o, Junior and Nevalainen, Helena (2013) Stress effects caused by the expression of a mutant cellobiohydrolase I and proteasome inhibition in trichoderma reesei rut-C30. New Biotechnology, 30 (2). pp. 183-191. ISSN 1871-6784 (Print) 1876-4347 (Online)

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Abstract

Trichoderma reesei Rut-C30 is used widely as an expression host for various gene products. We have explored cellular effects caused by the expression of a mutant form of cellobiohydrolase I (CBHI), the major secreted protein of T. reesei using biochemical and transcriptomic analyses and confocal laser scanning microscopy. The mutated CBHI was tagged fluorescently with Venus to establish the subcellular location of the fusion protein and its potential association with the proteasome, an organelle assigned for the disposal of misfolded proteins. Expression of the mutant CBHI in the high protein-secreting host Rut-C30 caused physiological changes in the fungal hyphae, affected protein secretion and elicited ER stress. A massive upregulation of UPR- and ERAD-related genes sec61, der1, uba1, bip1, pdi1, prp1, cxl1 and lhs1 was observed by qRT-PCR in the CBHIΔ4-Venus strain with four mutations introduced in the DNA encoding the core domain of CBHI. Further stress was applied to this strain by inhibiting function of the proteasome with MG132 (N-benzoylcarbonyl(Cbz)-Leu-Leu-leucinal). The effect of MG132 was found to be specific to the proteasome-associated genes. There are no earlier reports on the effect of proteasome inhibition on protein quality control in filamentous fungi. Confocal fluorescence microscopy studies suggested that the mutant CBHI accumulated in the ER and colocalized with the fungal proteasome. These results provide an indication that there is a limit to how far T. reesei Rut-C30, already under secretion stress, can be pressed to produce higher protein yields.
Item Type: Article
Subjects: Q Science > QH Natural history
Divisions: Faculty of Engineering and Natural Sciences > Academic programs > Biological Sciences & Bio Eng.
Faculty of Engineering and Natural Sciences
Depositing User: Günseli Bayram Akçapınar
Date Deposited: 07 Dec 2012 15:00
Last Modified: 31 Jul 2019 14:28
URI: https://research.sabanciuniv.edu/id/eprint/20197

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