PT  - JOURNAL ARTICLE
AU  - Mojtaba Samoudi
AU  - Chih-Chung Kuo
AU  - Caressa M. Robinson
AU  - Km Shams-Ud-Doha
AU  - Song-Min Schinn
AU  - Stefan Kol
AU  - Linus Weiss
AU  - Sara Petersen Bjorn
AU  - Bjorn G. Voldborg
AU  - Alexandre Rosa Campos
AU  - Nathan E. Lewis
TI  - In situ detection of protein interactions for recombinant therapeutic enzymes
AID  - 10.1101/2020.05.06.081885
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.05.06.081885
4099  - http://biorxiv.org/content/early/2020/05/07/2020.05.06.081885.short
4100  - http://biorxiv.org/content/early/2020/05/07/2020.05.06.081885.full
AB  - Despite their therapeutic potential, many protein drugs remain inaccessible to patients since they are difficult to secrete. Each recombinant protein has unique physicochemical properties and requires different machinery for proper folding, assembly, and post-translational modifications (PTMs). Here we aimed to identify the machinery supporting recombinant protein secretion by measuring the protein-protein interaction (PPI) networks of four different recombinant proteins (SERPINA1, SERPINC1, SERPING1 and SeAP) with various PTMs and structural motifs using the proximity-dependent biotin identification (BioID) method. We identified PPIs associated with specific features of the secreted proteins using a Bayesian statistical model, and found proteins involved in protein folding, disulfide bond formation and N-glycosylation were positively correlated with the corresponding features of the four model proteins. Among others, oxidative folding enzymes showed the strongest association with disulfide bond formation, supporting their critical roles in proper folding and maintaining the ER stability. Knock down of ERP44, a measured interactor with the highest fold change, led to the decreased secretion of SERPINC1, which relies on its extensive disulfide bonds. Proximity-dependent labeling successfully identified the transient interactions supporting synthesis of secreted recombinant proteins and refined our understanding of key molecular mechanisms of the secretory pathway during recombinant protein production.Competing Interest StatementThe authors have declared no competing interest.