Distinct roles of the two isoforms of the dynamin-like GTPase Mgm1 in mitochondrial fusion.
The mitochondrial dynamin-like GTPase Mgm1 exists as a long (l-Mgm1) and a short isoform (s-Mgm1). They both are essential for mitochondrial fusion. Here we show that the isoforms interact in a homotypic and heterotypic manner. Their submitochondrial distribution between inner boundary membrane and cristae was markedly different. Overexpression of l-Mgm1 exerts a dominant negative effect on mitochondrial fusion. A functional GTPase domain is required only in s-Mgm1 but not in l-Mgm1. We propose that l-Mgm1 acts primarily as an anchor in the inner membrane that in concert with the GTPase activity of s-Mgm1 mediates the fusion of inner membranes.
Zick
Michael
M
Adolf-Butenandt-Institut für Physiologische Chemie, Ludwig-Maximilians-Universität München, München, Germany.
Duvezin-Caubet
Stéphane
S
Schäfer
Anja
A
Vogel
Frank
F
Neupert
Walter
W
Reichert
Andreas S
AS
D034281:Dynamins / Q000737:chemistry / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008561:Membrane Fusion / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
C082883:MGM1 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D020033:Protein Isoforms; D029701:Saccharomyces cerevisiae Proteins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D034281:Dynamins