BAR scaffolds drive membrane fission by crowding disordered domains

Abstract

Cellular membranes are continuously remodeled. The crescent-shaped bin-amphiphysin-rvs (BAR) domains remodel membranes in multiple cellular pathways. Based on studies of isolated BAR domains in vitro, the current paradigm is that BAR domain–containing proteins polymerize into cylindrical scaffolds that stabilize lipid tubules. But in nature, proteins that contain BAR domains often also contain large intrinsically disordered regions. Using in vitro and live cell assays, here we show that full-length BAR domain–containing proteins, rather than stabilizing membrane tubules, are instead surprisingly potent drivers of membrane fission. Specifically, when BAR scaffolds assemble at membrane surfaces, their bulky disordered domains become crowded, generating steric pressure that destabilizes lipid tubules. More broadly, we observe this behavior with BAR domains that have a range of curvatures. These data suggest that the ability to concentrate disordered domains is a key driver of membrane remodeling and fission by BAR domain–containing proteins.

Protein Amphipathic Helix Insertion: A Mechanism to Induce Membrane Fission

“…Class II: Passive mechanism, normal topology. Examples: fission mediated, in the absence of nucleoside triphosphate hydrolysis, by Bacillus subtilis FisB (Doan et al, 2013), C-terminal Binding Protein 1 Short form/Brefeldin A ADP-Ribosylation substrate (CtBP1-S/BARS) (Spanò et al, 1999;Weigert et al, 1999;Hidalgo Carcedo et al, 2004;Valente et al, 2005Valente et al, , 2012Liberali et al, 2008;Pagliuso et al, 2016;Zhukovsky et al, 2019b), and by numerous AH-containing proteins, such as endophilins (Rostovtseva et al, 2009;Ambroso et al, 2014;Genet et al, 2019), amphiphysins (Wu and Baumgart, 2014;Snead et al, 2019), epsins (Ford et al, 2002;Boucrot et al, 2012;Brooks et al, 2015), α-synuclein (Nakamura et al, 2011;Braun et al, 2017;Pozo Devoto and Falzone, 2017;Fakhree et al, 2019), GDAP1 (Huber et al, 2016), ankyrin repeats and KH domain-containing protein 1 (ANKHD1) (Kitamata et al, 2019), Saccharomyces cerevisiae Atg18 (Gopaldass et al, 2017), Agrobacterium tumefaciens PmtA (Danne et al, 2017b), EcMurG (van den Brink-van der Laan et al, 2003, Acholeplasma laidlawii MGS (Eriksson et al, 2009;Ariöz et al, 2014;Ge et al, 2014) and DGS (Eriksson et al, 2009).…”

“…Amphipathic helix-containing fission-inducing proteins are recognized as a separate superfamily of scission factors (Gallop et al, 2006;Boucrot et al, 2012;Martyna et al, 2017). Among these proteins there are: Arf1 (Krauss et al, 2008;Beck et al, 2011;Bottanelli et al, 2017;Dodonova et al, 2017), Sar1 (Bielli et al, 2005;Lee et al, 2005;Bacia et al, 2011;Hariri et al, 2014;Hanna et al, 2016;Melero et al, 2018), epsins (Ford et al, 2002;Boucrot et al, 2012;Brooks et al, 2015), CALM (Miller et al, 2015), endophilin A1 (Gallop et al, 2006;Ambroso et al, 2014), endophilin A2 (Boucrot et al, 2015;Renard et al, 2015;Simunovic et al, 2017;Genet et al, 2019), endophilin A3 (Boucrot et al, 2012), endophilin B1 (Rostovtseva et al, 2009;Takahashi et al, 2016), mammalian amphiphysin 1 (Snead et al, 2019) and amphiphysin 2 (Wu and Baumgart, 2014), Drosophila amphiphysin (Isas et al, 2015), PICK1 (Karlsen et al, 2015), α-synuclein (Nakamura et al, 2011;Braun et al, 2017;Pozo Devoto and Falzone, 2017;Fakhree et al, 2019), GDAP1 (Huber et al, 2016), caveolin-1 (Parton et al, 2006;Kirkham et al, 2008;…”

“…Influenza virus M2 mediates class IV fission reaction. However, some AH-containing proteins, such as endophilin B1 and amphiphysin 1, could be involved, in complex with mechanoenzymes belonging to the dynamin superfamily, in class I fission reactions (Takahashi et al, 2016;Takeda et al, 2018), or, in the absence of mechanoenzymes, in class II fission reactions (Rostovtseva et al, 2009;Snead et al, 2019). Hence, belonging to a certain class is a property of the process, not a property of the protein molecule.…”

“…Bin/Amphiphysin/Rvs domain protein PICK1 contains an internal AH (Karlsen et al, 2015;Herlo et al, 2018). Mammalian endophilins A1 (Gallop et al, 2006;Ambroso et al, 2014), A2 (Boucrot et al, 2015;Renard et al, 2015;Simunovic et al, 2017;Genet et al, 2019), A3 (Boucrot et al, 2012) and B1 (Rostovtseva et al, 2009;Takahashi et al, 2016), mammalian amphiphysin 1 (Snead et al, 2019) and amphiphysin 2 (Wu and Baumgart, 2014), Drosophila amphiphysin (Isas et al, 2015), as well as mammalian PICK1 (Karlsen et al, 2015) are all involved in membrane fission. The AHs were suggested to generate membrane curvature and to play a role in membrane fission mediated by endophilins (Gallop et al, 2006;Masuda et al, 2006;Boucrot et al, 2012;Yoon et al, 2012) and amphiphysins (Peter et al, 2004;Boucrot et al, 2012;Yoon et al, 2012;Wu and Baumgart, 2014).…”

An implicit lipid model for efficient reaction-diffusion simulations of protein binding to surfaces of arbitrary topology

“…electrostatic attraction and repulsion), some molecular features are implicitly represented by the lipid density and binding rate. This simpler model is a necessary starting point for ultimately capturing how binding responds to collective changes of the surface, such as curvature [3,47,48]. Ⅱ.…”