Zhou, WenqingHsu, Alan Y.Wang, YueyangSyahirah, RamizahWang, TianqiJeffries, JacobWang, XuMohammad, HaroonSeleem, Mohamed N.Umulis, DavidDeng, Qing2020-12-102020-12-102020-090021-9533jcs248880http://hdl.handle.net/10919/101062Neutrophils rely on glycolysis for energy production. How mitochondria regulate neutrophil function is not fully understood. Here, we report that mitochondrial outer membrane protein Mitofusin 2 (MFN2) regulates neutrophilhomeostasis andchemotaxis in vivo. Mfn2-deficientneutrophils are released from the hematopoietic tissue, trapped in the vasculature in zebrafish embryos, and not capable of chemotaxis. Consistent with this, human neutrophil-like cells that are deficient for MFN2 fail to arrest on activated endothelium under sheer stress or perform chemotaxis on 2D surfaces. Deletion of MFN2 results in a significant reduction of neutrophil infiltration to the inflamed peritoneal cavity in mice. Mechanistically, MFN2-deficient neutrophil-like cells display disrupted mitochondria-ER interaction, heightened intracellular Ca2+ levels and elevated Rac activation after chemokine stimulation. Restoring a mitochondria-ER tether rescues the abnormal Ca2+ levels, Rac hyperactivation and chemotaxis defect resulting from MFN2 depletion. Finally, inhibition of Rac activation restores chemotaxis in MFN2-deficient neutrophils. Taken together, we have identified that MFN2 regulates neutrophil migration via maintaining the mitochondria-ER interaction to suppress Rac activation, and uncovered a previously unrecognized role of MFN2 in regulating cell migration and the actin cytoskeleton. This article has an associated First Person interview with the first authors of the paper.application/pdfenCreative Commons Attribution 4.0 InternationalMitochondriaChemotaxisRacZebrafishActinLeukocyteArticle - Refereedhttps://doi.org/10.1242/jcs.24888013317327882321477-9137