[Identification of phosphatidic acid interacting proteins in Ganoderma lingzhi]

Ganoderma lingzhi is widely recognized as a medicinal basidiomycetes. Triterpene acids (TAs) are the key bioactive medicinal components of G. lingzhi. Our previous studies have shown that phospholipid acid (PA) produced by phospholipase D (PLD) plays a regulatory role in TA synthesis. In order to further elucidate the molecular mechanism how PA regulates TA synthesis in G. lingzhi, PA beads enrichment combined with LC-MS/MS technology was used to identify PA interacting proteins in G. lingzhi. A total of 19 PA interacting proteins were identified, including cytochrome P450 monooxygenase (GL22084), specific protein kinase MAPK (GL23765), catalase and cell surface hydrophobicity-associated protein. GST tagged GL22084 and GL23765 proteins were obtained through gene cloning, heterologous expression, and purification. The interactions between GL22084/GL23765 and PA were verified by GST pull down assay. The identification of PA interacting proteins provides a basis for further understanding the molecular mechanism how PLD-mediated PA signaling molecules regulates the TA synthesis in G. lingzhi. Moreover, the PA interacting proteins identified in this study can also provide clues for the research of PLD/PA signaling pathway in other species.