Mitochondrial dynamics protein MID51 (MIEF1)

Mitochondrial dynamics protein MID51 (MIEF1) is an integral protein of the mitochondrial outer membrane, vertebrate-specific, and a key regulator of mitochondrial morphology. MIEF1 recruits cytosolic dynamin-related protein 1 (Drp1) to the mitochondrial surface and binds both Drp1 and hFis1, coordinating and fine-tuning the balance between mitochondrial fission and fusion. Overexpression of MIEF1 inhibits Drp1-mediated mitochondrial fission by sequestering Drp1 in an inactive state, leading to elongated (fused) mitochondria, while depletion results in excessive mitochondrial fragmentation. This regulation is critical for normal organelle function and cellular health, and dominant mutations in MIEF1 have been linked to neurodegenerative diseases such as optic neuropathy[1][2][3][4][5].

Other names

Mitochondrial elongation factor 1MIEF1MID51SMCR7LMiD51SMCR7-like proteinDANGER family member 3AMitochondrial dynamics protein of 51 kDaFLJ20232OPA14MIEF1-MPAltMIEF1Alternative MIEF1 proteinMIEF1 microproteinD3AL0R8F8dJ1104E15.3Smith-Magenis syndrome chromosomal region candidate gene 7 protein-likeMIEF1 upstream open reading frame proteinMitochondrial ribosome and complex I assembly factor AltMIEF1Alternative transcript upstream of MiD51

Drp1 (dynamin-related protein 1) recruitment and inhibition—MIEF1 binds and recruits Drp1 to mitochondria but suppresses Drp1’s GTPase activity and impedes mitochondrial fission, thus promoting fusion[1][2][3][5].