STAT6 in mitochondrial outer membrane impairs mitochondrial fusion by inhibiting MFN2 dimerization

Although it is reported that mitochondria-localized nuclear transcription factors (TFs) regulate mitochondrial processes such as apoptosis and mitochondrial transcription/respiration, their functions and mechanisms of mitochondrial dynamics regulated by mitochondria-localized nuclear TFs are yet to be fully characterized. Here, we identify STAT6 as a mitochondrial protein that is localized in the outer membrane of mitochondria (OMM). In addition to regulating mitochondrial gene expression as a nuclear TF, STAT6 in OMM inhibits mitochondrial fusion by blocking MFN2 dimerization. This implies that STAT6 has dual role in overall mitochondrial process. Moreover, mitochondrial accumulation of STAT6 in response to these findings reveal that STAT6 is a new regulator of mitochondrial processes including mitochondrial biogenesis and fusion/fission mechanisms. To further investigate the role of STAT6 in sustaining mitochondrial gene expression, we performed RNA sequencing (RNA-seq) profiling of Mock-mCherry+ and STAT6 WT-mCherry+ 293T cells.