Biophysical Society Thematic Meeting - October 13-15, 2015

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.

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