6FGZ

Structure of a mitochondrial fission dynamin in the closed conformation.

(2018) Nat Struct Mol Biol 25: 722-731

• PubMed: 30061604 Search on PubMedSearch on PubMed Central
• DOI: https://doi.org/10.1038/s41594-018-0097-6
• Primary Citation of Related Structures:  
  6FGZ


• PubMed Abstract: 
  

  Dynamin 1-like proteins (DNM1-L) are mechanochemical GTPases that induce membrane fission in mitochondria and peroxisomes. Their mechanism depends on conformational changes driven by nucleotide and lipid cycling. Here we show the crystal structure of a mitochondrial fission dynamin (CmDnm1) from the algae Cyanidioschyzon merolae. Unlike other eukaryotic dynamin structures, CmDnm1 is in a hinge 1 closed conformation, with the GTPase domain compacted against the stalk. Within the crystal, CmDnm1 packs as a diamond-shaped tetramer that is consistent with an inactive off-membrane state. Crosslinking, photoinduced electron transfer assays, and electron microscopy verify these structures. In vitro, CmDnm1 forms concentration-dependent rings and protein-lipid tubes reminiscent of DNM1-L and classical dynamin with hinge 1 open. Our data provides a mechanism for filament collapse and membrane release that may extend to other dynamin family members. Additionally, hinge 1 closing may represent a key conformational change that contributes to membrane fission.

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Organizational Affiliation: 

Department of Life Sciences, Imperial College, London, UK.