Expression Characterization of AtPDI11 and Functional Analysis of AtPDI11 D Domain in Oxidative Protein Folding

Abstract

The formation and isomerization of disulfide bonds mediated by protein disulfide isomerase (PDI) in the endoplasmic reticulum (ER) is of fundamental importance in eukaryotes. Canonical PDI structure comprises four domains with the order of a-b-b’-a’. In Arabidopsis thaliana, the PDI-S subgroup contains only one member, AtPDI11, with an a-a’-D organization, which has no orthologs in mammals or yeast. However, the expression pattern of AtPDI11 and the functioning mechanism of AtPDI11 D domain are currently unclear. In this work, we found that PDI-S is evolutionarily conserved between land plants and algal organisms. AtPDI11 is expressed in various tissues and its induction by ER stress is disrupted in bzip28/60 and ire1a/b mutants that are null mutants of key components in the unfolded protein response (UPR) signal transduction pathway, suggesting that the induction of AtPDI11 by ER stress is mediated by the UPR signaling pathway. Furthermore, enzymatic activity assays and genetic evidence showed that the D domain is crucially important for the activities of AtPDI11. Overall, this work will help to further understand the working mechanism of AtPDI11 in catalyzing disulfide formation in plants.

Integrated Transcriptome and Proteome Analysis Reveals the Regulatory Mechanism of Root Growth by Protein Disulfide Isomerase in Arabidopsis

“…Compound 16F16, containing a chloroacetyl moiety, was observed to covalently bind to its target protein, resulting in the inhibition of the target protein's activity [25]. The Arabidopsis PDI family contains 14 family members with functional redundancy [26]. Previously, the investigation of PDI functions has mainly focused on embryos, embryo sac development, and the oxidative folding of storage proteins.…”