Interaction of PASTICCINO2 with Golgi anti-apoptotic proteins confers resistance to endoplasmic reticulum stress and is dependent on very-long-chain fatty acids.

This article focuses on the role of PASTICCINO2 (PAS2), a key enzyme in very-long-chain fatty acid (VLCFA) synthesis, and its interaction with GOLGI ANTI-APOPTOTIC PROTEINS (GAAPs) in regulating the unfolded protein response (UPR) and resistance to endoplasmic reticulum (ER) stress in Arabidopsis thaliana. The study demonstrates that PAS2 physically interacts with GAAPs and INOSITOL REQUIRING ENZYME 1 (IRE1), and that mutations in PAS2 and GAAPs increase plant sensitivity to ER stress, impair UPR maintenance during chronic stress, and reduce VLCFA levels. Exogenous application of VLCFAs partially restores UPR activity in mutants, indicating that PAS2's role in ER stress resistance depends on its VLCFA synthesis domain. These findings reveal a novel lipid-mediated mechanism by which PAS2 and GAAPs cooperate to modulate UPR signaling and promote plant survival under prolonged ER stress.