Journal Article Research Support, Non-U.S. Gov't Ppublish 5 citations
PubMed: 37925033 DOI: 10.1016/j.bbagen.2023.130502
DNAJB12 and DNJB14 are non-redundant Hsp40 redox chaperones involved in endoplasmic reticulum protein reflux.
Biochim Biophys Acta Gen Subj 1868(1):130502
Authors: Aline Dias da Purificação, Victor Debbas, Leonardo Yuji Tanaka, Gabriele Verônica de Mello Gabriel, João Wosniak Júnior, Tiphany Coralie De Bessa, Sheila Garcia-Rosa, Francisco Rafael Martins Laurindo, Percillia Victoria Santos Oliveira
Affiliations
- Laboratorio de Biologia Vascular, LIM-64 (Biologia Cardiovascular Translacional), Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.
- Brazilian Bioscience National Laboratory - LNBio, National Center Research in Energy and material - CNPEM, Campinas, Brazil.
- Laboratorio de Biologia Vascular, LIM-64 (Biologia Cardiovascular Translacional), Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.
Abstract
BACKGROUND
The endoplasmic reticulum (ER) transmembrane chaperones DNAJB12(B12) and DNAJB14(B14) are cofactors that cooperate with cytosolic Heat Shock-70 protein (HSC70) facilitating folding/degradation of nascent membrane proteins and supporting the ER-membrane penetration of viral particles. Here, we assessed structural/functional features of B12/B14 with respect to their regulation by ER stress and their involvement in ER stress-mediated protein reflux.
METHODS
We investigated the effect of Unfolded Protein Response(UPR)-eliciting drugs on the expression/regulation of B12-B14 and their roles in ER-to-cytosol translocation of Protein Disulfide Isomerase-A1(PDI).
RESULTS
We show that B12 and B14 are similar but do not seem redundant. They share predicted structural features and show high homology of their cytosolic J-domains, while their ER-lumen DUF1977 domains are quite dissimilar. Interactome analysis suggested that B12/B14 associate with different biological processes. UPR activation did not significantly impact on B12 gene expression, while B14 transcripts were up-regulated. Meanwhile, B12 and B14 (33.4 kDa isoform) protein levels were degraded by the proteasome upon acute reductive challenge. Also, B12 degradation was impaired upon sulfenic-acid trapping by dimedone. We originally report that knockdown of B12/B14 and their cytosolic partner SGTA in ER-stressed cells significantly impaired the amount of the ER redox-chaperone PDI in a cytosolic-enriched fraction. Additionally, B12 but not B14 overexpression increased PDI relocalization in non-stressed cells.
CONCLUSIONS AND GENERAL SIGNIFICANCE
Our findings reveal that B12/B14 regulation involves thiol redox processes that may impact on their stability and possibly on physiological effects. Furthermore, we provide novel evidence that these proteins are involved in UPR-induced ER protein reflux.
MeSH
Biochemistry, Biophysics, Stress, Physiological, Membranes, Cells, Endoplasmic Reticulum, Protein Disulfide-Isomerases, Cytosol