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Biophysics of Proteins at Surfaces: Assembly, Activation, Signaling
Poster Abstracts
38-POS
Board 38
Drp1 Polymerization Stabilizes Curved Tubular Membranes Similar to Those Found in
Mitochondria
B. Ugarte-Uribe
1
, Coline Prévost
2
, Patricia Bassereau
2
, Ana J. García-Sáez
1
.
1
Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen,
Germany,
2
Institut Curie, Centre de Recherche, F-75248 Paris, France.
Drp1, an 80-kDa mechanochemical GTPase of the dynamin superfamily, is required for
mitochondrial fission in mammals in a process dependent on Drp1 self-assembly and coupled to
GTP hydrolysis. Although dysfunction of Drp1 has been linked to human disease, there are still
some clues missing regarding the molecular mechanism of action of Drp1 on membranes that
remain to be elusive. As dynamin, Drp1 is thought to form helical coat circling a membrane
tubule leading to membrane deformation. To study the effect of Drp1 in membrane curvature we
used preformed tubes pulled from GUVs under near-physiological conditions. In the presence of
GTP a fast Drp1 polymerization along the preformed tube was observed, where Drp1 coating
preserved the membrane tube within it. In addition, Drp1 rearrangement on membranes from
homogeneous binding to the formation of nucleation points was shown to be enough to stabilize
a narrow range of radii akin to Drp1 nucleation foci found in cell mitochondria. This suggests
that Drp1 could play a role as curvature stabilizer which sets it apart from other dynamin
homologs and may be relevant for the molecular mode of action of Drp1 in the context of the
cell.