Real-time detection reveals that effectors couple dynamin's GTP-dependent conformational changes to the membrane

Ramachandran, Rajesh; Schmid, Sandra L.

doi:10.1038/sj.emboj.7601961

Cited by 103 publications

(152 citation statements)

References 55 publications

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“…In wild-type mammalian cells, because actin burst occurs in the latter part of endocytosis, actin-induced stress could assist dynamin in scission. In addition, actin-induced in-plane stress in the neck domain could facilitate dynamin polymerization (60). This idea is supported by the recent work of Campelo and Kozlov (61), which predicts that high stress facilitates insertion of shallow proteins within the bilayer.…”

Section: Discussionsupporting

confidence: 66%

Endocytic proteins drive vesicle growth via instability in high membrane tension environment

Walani

Torres

Agrawal

2015

Proc. Natl. Acad. Sci. U.S.A.

102

152

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Clathrin-mediated endocytosis (CME) is a key pathway for transporting cargo into cells via membrane vesicles; it plays an integral role in nutrient import, signal transduction, neurotransmission, and cellular entry of pathogens and drug-carrying nanoparticles. Because CME entails substantial local remodeling of the plasma membrane, the presence of membrane tension offers resistance to bending and hence, vesicle formation. Experiments show that in such high-tension conditions, actin dynamics is required to carry out CME successfully. In this study, we build on these pioneering experimental studies to provide fundamental mechanistic insights into the roles of two key endocytic proteins-namely, actin and BAR proteins-in driving vesicle formation in high membrane tension environment. Our study reveals an actin force-induced "snapthrough instability" that triggers a rapid shape transition from a shallow invagination to a highly invaginated tubular structure. We show that the association of BAR proteins stabilizes vesicles and induces a milder instability. In addition, we present a rather counterintuitive role of BAR depolymerization in regulating the shape evolution of vesicles. We show that the dissociation of BAR proteins, supported by actin-BAR synergy, leads to considerable elongation and squeezing of vesicles. Going beyond the membrane geometry, we put forth a stress-based perspective for the onset of vesicle scission and predict the shapes and composition of detached vesicles. We present the snap-through transition and the high in-plane stress as possible explanations for the intriguing direct transformation of broad and shallow invaginations into detached vesicles in BAR mutant yeast cells.clathrin-mediated endocytosis | membrane tension | instability | actin | BAR proteins

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Section: Discussionsupporting

confidence: 66%

Endocytic proteins drive vesicle growth via instability in high membrane tension environment

Walani

Torres

Agrawal

2015

Proc. Natl. Acad. Sci. U.S.A.

102

152

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“…Through direct SH3-PRD interactions, these proteins can regulate dynamin self-assembly, GTPase activity and membrane binding (25)(26)(27)(28)(29)(30)(31). In order to uncouple the effect of curvature generation by their BAR domains from other effects on dynamin activity, we initially tested the ability of these proteins to synergize with truncated Dyn2 lacking its PRD (Dyn2⌬PRD).…”

Section: Full-length Endophilin and Amphiphysin But Not Snx9 Stimulatmentioning

confidence: 99%

“…In vitro studies have shown that these proteins can also regulate dynamin self-assembly, membrane binding, and GTPase activity (25)(26)(27)(28)(29)(30)(31). Thus, these proteins are good candidates for EAPs that could function, together with Dyn2, to enhance fission.…”

mentioning

confidence: 99%

Dual Role of BAR Domain-containing Proteins in Regulating Vesicle Release Catalyzed by the GTPase, Dynamin-2

Neumann

Schmid

2013

Journal of Biological Chemistry

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Background: Membrane curvature generation is essential for dynamin-2-catalyzed membrane fission and vesicle release. Results: Dynamin-2 binding partners with curvature generating activity differentially regulate the assembly, GTPase, and fission activities of dynamin-2. Conclusion: Dynamin-2 partners display complex patterns of regulation. Significance: The distinct functional interactions between dynamin-2 and its binding partners position them to contribute to the spatio-temporal regulation of clathrin-mediated endocytosis.

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“…Because the final tubules are circled by dynamin helices (8,20), it is thought that dynamin polymerization provides the energy needed to deform the liposome membranes into a highly curved tubular structure. Another explanation is that hydrophobic loops present in the PH domain of dynamin (18) could generate spontaneous curvature like the BAR domain structure (21), and that polymerization would just be required to stabilize the tubular shape. To discriminate between these hypotheses, forces and energies involved in polymerization have to be measured.…”

mentioning

confidence: 99%

“…Dynamin can also polymerize around preformed lipid nanorods of typically 10-to 15-nm radius containing PIP 2 (16) and around microtubules, onto which it was first purified (17). Binding of dynamin to liposomes has been shown to depend on liposome size (18), and theoretical calculations suggest that dynamin could be recruited by curvaturedriven long-range interactions between membrane-bound dimers of dynamin (19). Taken together, these observations may indicate that dynamin polymerizes preferentially along cylindrical structures with a radius close to its spontaneous radius of curvature.…”

mentioning

confidence: 99%

Membrane curvature controls dynamin polymerization

Roux

Koster

Lenz

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

277

270

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The generation of membrane curvature in intracellular traffic involves many proteins that can curve lipid bilayers. Among these, dynamin-like proteins were shown to deform membranes into tubules, and thus far are the only proteins known to mechanically drive membrane fission. Because dynamin forms a helical coat circling a membrane tubule, its polymerization is thought to be responsible for this membrane deformation. Here we show that the force generated by dynamin polymerization, 18 pN, is sufficient to deform membranes yet can still be counteracted by high membrane tension. Importantly, we observe that at low dynamin concentration, polymer nucleation strongly depends on membrane curvature. This suggests that dynamin may be precisely recruited to membrane buds' necks because of their high curvature. To understand this curvature dependence, we developed a theory based on the competition between dynamin polymerization and membrane mechanical deformation. This curvature control of dynamin polymerization is predicted for a specific range of concentrations (∼0.1-10 μM), which corresponds to our measurements. More generally, we expect that any protein that binds or self-assembles onto membranes in a curvature-coupled way should behave in a qualitatively similar manner, but with its own specific range of concentration.force | nucleation | fission | endocytosis | dynamin-like proteins M embrane remodeling is an essential task of proteins involved in membrane traffic (1, 2). Dynamin is a large GTPase that has been shown to polymerize into a helical collar at the neck of endocytic buds (3), where it subsequently plays a key role in the formation of endocytic vesicles through fission (4-8). This function is fundamental, as the knockout of the dynamin neuronal isoform leads to striking defects in synapse organization and results in a strong dysfunction of neuronal activity (9). The recruitment of dynamin to endocytic buds is thought to depend on the local synthesis of phosphatidylinositol(4,5)bisphosphate (PIP 2 ), as dynamin has a PIP 2 binding pleckstrin homology (PH) domain (10). Dynamin is recruited late in clathrin-coated vesicle formation, as seen by total internal reflection fluorescence (TIRF) microscopy (11-13). Because PIP 2 is also responsible for the binding of clathrin coats, it is expected to be present at the clathrin bud from the beginning of its formation. Thus, another explanation was suggested: Proteins that interact with dynamin and possess a curvature-sensing Bin-Amphiphysin-Rvs (BAR) domain (such as endophilin and amphiphysin) were proposed to sense the high curvature of the neck and recruit dynamin (14). Because the curvature of the neck is increasing during clathrin-coated vesicle formation to finally reach the range needed for BAR recruitment, this could explain the arrival of dynamin at the very late stage of clathrin-coated vesicle formation. However, in solution, dynamin spontaneously associates into helices and rings (15) with an internal radius of ≈10 nm. Dynamin can also polymerize around pre...

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Real-time detection reveals that effectors couple dynamin's GTP-dependent conformational changes to the membrane

Cited by 103 publications

References 55 publications

Endocytic proteins drive vesicle growth via instability in high membrane tension environment

Endocytic proteins drive vesicle growth via instability in high membrane tension environment

Dual Role of BAR Domain-containing Proteins in Regulating Vesicle Release Catalyzed by the GTPase, Dynamin-2

Membrane curvature controls dynamin polymerization

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