Mitochondrial fission factor is a tail-anchored protein that resides within the outer mitochondrial membrane and is part of the mitochondrial fission complex. MFF participates in mitochondrial fission by serving as one of multiple receptors for the GTPase dynamin-related protein 1. Research studies have also shown that MFF is a peroxisomal membrane protein and participates in peroxisome fission by serving as a receptor for another GTPase, dynamin-like protein 1.Research studies have demonstrated that the ability of MFF to drive acute mitochondrial fission in response to mitochondrial stress is controlled by AMPK-dependent phosphorylation. AMPK directly phosphorylates MFF at two sites to allow for enhanced recruitment of Drp1 to the mitochondra. Multiple isoforms of MFF are expressed as a result of alternative splicing. One of the major phosphoacceptor sites of MFF lies within an AMPK phsophorylation motif that spans the boundary of differentially spliced exons of MFF isoforms, suggesting that MFF splice isoforms are phosphorylated by AMPK to varying degrees.
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