RT Journal Article
SR Electronic
T1 Membrane bending energy and tension govern mitochondrial division
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 255356
DO 10.1101/255356
A1 Dora Mahecic
A1 Lina Carlini
A1 Tatjana Kleele
A1 Adai Colom
A1 Antoine Goujon
A1 Stefan Matile
A1 Aurélien Roux
A1 Suliana Manley
YR 2019
UL http://biorxiv.org/content/early/2019/03/25/255356.abstract
AB Many molecular factors required for mitochondrial division have been identified; however, how they combine to physically trigger division remains unknown. Here, we report that constriction by the division machinery does not ensure mitochondria will divide. Instead, potential division sites accumulate molecular components and can constrict before either dividing, or relaxing back to an unconstricted state. Using time-lapse structured illumination microscopy (SIM), we find that constriction sites with higher local curvatures – reflecting an increased membrane bending energy – are more likely to divide. Furthermore, analyses of mitochondrial motion and shape changes demonstrate that dividing mitochondria are typically under an externally induced membrane tension. This is corroborated by measurements using a newly synthesized fluorescent mitochondrial membrane tension sensor, which reveal that depolymerizing the microtubule network diminishes mitochondrial membrane tension. We find that under reduced tension, the number of constrictions is maintained, but the probability that constrictions will divide is concomitantly reduced. These measurements allow us to establish a physical model, based on in situ estimates of membrane bending energy and tension, which accounts for the observed fates of mitochondrial constriction events.