Putative Interaction Proteins of the Ubiquitin Ligase Hrd1 in Magnaporthe oryzae.

Abstract

The endoplasmic reticulum (ER) is the entry portal of the conventional secretory pathway where the newly synthesized polypeptides fold, modify, and assemble. The ER responses to the unfolded proteins in its lumen (ER stress) by triggering intracellular signal transduction pathways include the ER-associated degradation (ERAD) pathway and the unfolded protein response (UPR) pathway. In yeast and mammals, the ubiquitin ligase Hrd1 is indispensable for the ERAD pathway, and also Hrd1-mediated ERAD pathway plays a crucial role in maintaining homeostasis and metabolism of human beings. However, the underlying physiological roles and regulatory mechanism of the Hrd1-involved ERAD pathway in the plant pathogenic fungi are still unclear. Here, we identified the Hrd1 orthologous proteins from 9 different fungi and noticed that these Hrd1 orthologs are conserved. Through identification of MoHrd1 putative interacting proteins by co-immunoprecipitation assays and enrichment analysis, we found that MoHrd1 is involved in the secretory pathway, energy synthesis, and metabolism. Taken together, our results suggest that MoHrd1 is conserved among fungi and play an important role in cellular metabolism and infection-related development. Our finding helps uncover the mechanism of Hrd1-involved ERAD pathway in fungi and sheds a new light to understand the pathogenic mechanism of Magnaporthe oryzae.