1 Harnessing secretory pathway differences between HEK293 and CHO to rescue production of difficult to express proteins Magdalena Malm 1* , Chih-Chung Kuo 2,3* , Mona Moradi Barzadd 1 , Aman Mebrahtu 1 , Num Wistbacka 1 , Ronia Razavi 1 , Anna-Luisa Volk 1 , Magnus Lundqvist 1 , David Kotol 4 , Fredrik Edfors 4 , Torbjörn Gräslund 1 ; Veronique Chotteau 5 , Ray Field 6 , Paul G. Varley 6,7 , Robert G. Roth 8 , Nathan E. Lewis 2,3 , Diane Hatton 6 , Johan Rockberg 1 1 Dept. of Protein science; KTH - Royal Institute of Technology; Stockholm; SE-106 91; Sweden 2 Departments of Pediatrics and Bioengineering; University of California; San Diego, La Jolla; CA 92093; USA 3 The Novo Nordisk Foundation Center for Biosustainability at the University of California; San Diego; CA 92093; USA 4 Science for Life Laboratory; KTH - Royal Institute of Technology; Solna; 171 65; Sweden 5 Dept. of Industrial Biotechnology; KTH – Royal Institute of Technology; Stockholm; SE- 10691, Sweden 6 Cell Culture and Fermentation Sciences, BioPharmaceutical Development, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK 7 Kymab, Babraham Research Campus, Cambridge CB22 3AT, UK 8 Discovery Biology, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden *These authors contributed equally to this work Corresponding authors: Johan Rockberg, KTH - Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, S- 106 91 Stockholm, Sweden E-mail: johan.rockberg@biotech.kth.se Office: +46 8 790 99 88 Fax: +46 8 5537 8481 Or: Nathan E. Lewis, University of California; San Diego, Departments of Pediatrics and Bioengineering; La Jolla; CA 92093; USA E-mail: n4lewis@eng.ucsd.edu Phone: +1 858 997 5944 (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. The copyright holder for this preprint this version posted August 17, 2021. ; https://doi.org/10.1101/2021.08.16.455786 doi: bioRxiv preprint