H3K27me3 ChIP-seq in Ranbp2 Wild-type and knockout 10T1/2 cells

Mitochondria regulate cellular processes through direct and indirect interactions with other organelles. A well-studied example is contact with the endoplasmic reticulum at mitochondrial-associated ER membranes (MAMs), which control pathways including redox and calcium homeostasis. Recent studies also reported direct mitochondria–nuclear membrane contacts in cancer cells and yeast that promote pro-survival signaling, but how exchange occurs across two largely impermeable membranes remains unclear. Here, we describe the existence of direct interactions between the nuclear pore and the mitochondria. In two unbiased proteomic screens, GST pulldown and BioID, VDAC1 was the top mitochondrial candidate that interacts with the nuclear pore protein RANBP2. In vitro RANBP2 CRISPR knock-out, RANBP2 truncation, or site directed mutagenesis of RANBP2-interacting amino acids in VDAC1 resulted in reduced mitochondria-nucleus proximity and decreased nuclear ATP and phosphocreatine levels. This was accompanied by a decline in levels of the nuclear phosphoproteome, and downregulation of pathways involved in histone modification, cellular differentiation and transcriptional regulation in vitro. We show differential H3K27me3 histone epigenetic landscape in Ranbp2 Wildtype and knockout cells in 10T1/2. Moreover, deletion of RANBP2 C-terminal domain in vivo in mice resulted in embryonic lethality due to cardiac and neural crest differentiation defects. Collectively, these results describe a mechanism by which mitochondria directly interact with the NPC, a phenomenon which is critical for regulation nuclear energetics and cellular differentiation during embryonic development.