Coassembly of Mgm1 isoforms requires cardiolipin and mediates mitochondrial inner membrane fusion

Rachel M. DeVay, Lenin Dominguez-Ramirez, Laura L. Lackner, Suzanne Hoppins, Henning Stahlberg, Jodi Nunnari

Research output: Contribution to journalArticlepeer-review

187 Scopus citations

Abstract

Two dynamin-related protein (DRP) families are essential for fusion of the outer and inner mitochondrial membranes, Fzo1 (yeast)/Mfn1/Mfn2 (mammals) and Mgm1 (yeast)/Opa1 (mammals), respectively. Fzo1/Mfns possess two medial transmembrane domains, which place their critical GTPase and coiled-coil domains in the cytosol. In contrast, Mgm1/Opa1 are present in cells as long (l) isoforms that are anchored via the N terminus to the inner membrane, and short (s) isoforms were predicted to be soluble in the intermembrane space. We addressed the roles of Mgm1 isoforms and how DRPs function in membrane fusion. Our analysis indicates that in the absence of a membrane, l- and s-Mgm1 both exist as inactive GTPase monomers, but that together in trans they form a functional dimer in a cardiolipin-dependent manner that is the building block for higher-order assemblies.

Original languageEnglish (US)
Pages (from-to)793-803
Number of pages11
JournalJournal of Cell Biology
Volume186
Issue number6
DOIs
StatePublished - Sep 21 2009

ASJC Scopus subject areas

  • Cell Biology
  • Medicine(all)

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