MCL1 promotes porcine epidemic diarrhea virus replication by modulating arachidonic acid metabolic pathway

Porcine epidemic diarrhea virus (PEDV) poses a significant threat to the global swine industry; however, the host factors that support its replication remain poorly understood. Our previous study showed that myeloid cell leukemia 1 (MCL1) is a pro-PEDV replication cellular factor through genome-scale CRISPR-Cas9-knockout (KO) screening. Nevertheless, the molecular mechanism whereby MCL1 promotes PEDV replication is unclear. In this study, we first demonstrated that MCL1 promotes PEDV replication through its BCL-2 homology (BH) domain. Deletion of MCL1 prevented arachidonic acid (AA) from undergoing β-oxidation which led to the increase of free AA and activation of its secondary metabolic pathways resulting in significant inhibition of PEDV replication. Complementation of MCL1-KO cells with a BH domain fragment of MCL1 restored β-oxidation capacity and rescued PEDV replication. In addition, we identified acyl-CoA synthetase bubblegum family member 1 (ACSBG1) as a novel metabolic regulator that binds to the N-terminus of MCL1, rather than its BH domain, and cooperates with MCL1 to facilitate AA β-oxidation. We further demonstrated that ACSBG1 and MCL1 act together as proviral factors specifically during the replication stage of PEDV infection. In summary, this work reveals a unique and concerted interaction between MCL1 and ACSBG1 that function together to promote PEDV replication by regulating the AA metabolic pathway.