Transport of protein disulfide isomerase from the endoplasmic reticulum to the extracellular space without passage through the Golgi complex

Author(s)

Oliveira, Percillia Victoria Santos ; Dalla Torre, Marco ; Debbas, Victor ; Orsi, Andrea ; Laurindo, Francisco Rafael Martins ; Sitia, Roberto

• Document type: Journal article
• Source: Journal of Biological Chemistry; v. 300, n. 8, p. 12-pg., 2024-08-01.

Abstract

Protein disulfide isomerase-A1 (PDIA1) is a master regulator of oxidative protein folding and proteostasis in the endoplasmic reticulum (ER). However, PDIA1 can reach the extra cellular space, impacting thrombosis and other pathophysiological phenomena. Whether PDIA1 is externalized via passive release or active secretion is not known. To investigate how PDIA1 negotiates its export, we generated tagged variant that undergoes N-glycosylation in the ER (Glyco-PDIA1). Addition of N-glycans does not alter its enzymatic functions. Upon either deletion of its KDEL ER localization motif or silencing of KDEL receptors, GlycoPDIA1 acquires complex glycans in the Golgi and is secreted. In control cells, however, Glyco-PDIA1 is released with endoglycosidase-H sensitive glycans, implying that it does not follow the classical ER-Golgi route nor does it encounter glycanases in the cytosol. Extracellular Glyco-PDIA1 is more abundant than actin, lactate dehydrogenase, or other proteins released by damaged or dead cells, suggesting active transport through a Golgi-independent route. The strategy we describe herein can be extended to dissect how select ER-residents reach the extracellular space. (AU)

• FAPESP's process: 19/03617-5 - Cytosolic Protein Disulfide Isomerase-A1 (PDIA1): a novel thiol-redox mechanism in cell signaling
• Grantee: Percíllia Victória Santos de Oliveira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/07937-8 - Redoxome - Redox Processes in Biomedicine
• Grantee: Ohara Augusto
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 20/03193-8 - Unambiguous testing of dynamic cytosolic translocation of PDIA1
• Grantee: Percíllia Victória Santos de Oliveira
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor