scholarly journals An Amphipathic Helix Directs Cellular Membrane Curvature Sensing and Function of the BAR Domain Protein PICK1

Cell Reports ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 2056-2069 ◽  
Author(s):  
Rasmus Herlo ◽  
Viktor K. Lund ◽  
Matthew D. Lycas ◽  
Anna M. Jansen ◽  
George Khelashvili ◽  
...  
Keyword(s):  
Cellular Membrane ◽  
Membrane Curvature ◽  
Amphipathic Helix ◽  
Bar Domain ◽  
Curvature Sensing ◽  
Domain Protein ◽  
And Function

scholarly journals FAM92A1 is a BAR domain protein required for mitochondrial ultrastructure and function

2018 ◽  
Vol 218 (1) ◽  
pp. 97-111 ◽  
Author(s):  
Liang Wang ◽  
Ziyi Yan ◽  
Helena Vihinen ◽  
Ove Eriksson ◽  
Weihuan Wang ◽  
...  
Keyword(s):  
Mitochondrial Function ◽  
Molecular Mechanisms ◽  
Membrane Curvature ◽  
Mitochondrial Morphology ◽  
Membrane Remodeling ◽  
Mitochondrial Ultrastructure ◽  
Bar Domain ◽  
Bar Domain Proteins ◽  
Domain Protein

Mitochondrial function is closely linked to its dynamic membrane ultrastructure. The mitochondrial inner membrane (MIM) can form extensive membrane invaginations known as cristae, which contain the respiratory chain and ATP synthase for oxidative phosphorylation. The molecular mechanisms regulating mitochondrial ultrastructure remain poorly understood. The Bin-Amphiphysin-Rvs (BAR) domain proteins are central regulators of diverse cellular processes related to membrane remodeling and dynamics. Whether BAR domain proteins are involved in sculpting membranes in specific submitochondrial compartments is largely unknown. In this study, we report FAM92A1 as a novel BAR domain protein localizes to the matrix side of the MIM. Loss of FAM92A1 caused a severe disruption to mitochondrial morphology and ultrastructure, impairing organelle bioenergetics. Furthermore, FAM92A1 displayed a membrane-remodeling activity in vitro, inducing a high degree of membrane curvature. Collectively, our findings uncover a role for a BAR domain protein as a critical organizer of the mitochondrial ultrastructure that is indispensable for mitochondrial function.

scholarly journals An amphipathic helix enables septins to sense micrometer-scale membrane curvature

2019 ◽  
Vol 218 (4) ◽  
pp. 1128-1137 ◽  
Author(s):  
Kevin S. Cannon ◽  
Benjamin L. Woods ◽  
John M. Crutchley ◽  
Amy S. Gladfelter
Keyword(s):  
Membrane Curvature ◽  
Amphipathic Helix ◽  
Curvature Sensing ◽  
C Terminus ◽  
Number Of Binding Sites ◽  
Curved Membranes ◽  
Necessary And Sufficient ◽  
Micrometer Scale

Cell shape is well described by membrane curvature. Septins are filament-forming, GTP-binding proteins that assemble on positive, micrometer-scale curvatures. Here, we examine the molecular basis of curvature sensing by septins. We show that differences in affinity and the number of binding sites drive curvature-specific adsorption of septins. Moreover, we find septin assembly onto curved membranes is cooperative and show that geometry influences higher-order arrangement of septin filaments. Although septins must form polymers to stay associated with membranes, septin filaments do not have to span micrometers in length to sense curvature, as we find that single-septin complexes have curvature-dependent association rates. We trace this ability to an amphipathic helix (AH) located on the C-terminus of Cdc12. The AH domain is necessary and sufficient for curvature sensing both in vitro and in vivo. These data show that curvature sensing by septins operates at much smaller length scales than the micrometer curvatures being detected.

scholarly journals Comparative study of curvature sensing mediated by F-BAR domain and an intrinsically disordered region of FBP17

2020 ◽  
Author(s):  
Maohan Su ◽  
Yinyin Zhuang ◽  
Xinwen Miao ◽  
Yongpeng Zeng ◽  
Weibo Gao ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Membrane Trafficking ◽  
Membrane Curvature ◽  
Wave System ◽  
Common Belief ◽  
Bar Domain ◽  
Curvature Sensing ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Region

Membrane curvature has emerged as an intriguing physical organization principle underlying biological signaling and membrane trafficking. FBP17 of the CIP4/FBP17/Toca-1 F-BAR family is unique in the BAR family because its structurally folded F-BAR domain does not contain any hydrophobic motifs that insert into lipid bilayer. While it has been widely assumed so, whether the banana-shaped F-BAR domain alone can sense curvature has never been experimentally demonstrated. Using a nanopillar-supported lipid bilayer system, we found that the F-BAR domain of FBP17 displayed minimal curvature sensing in vitro. We further identified an alternatively spliced intrinsically disordered region (IDR) of FBP17 next to its F-BAR domain that is conserved in sequence across species. The IDR senses membrane curvature and its sensing ability greatly exceeds that of F-BAR domain alone. In living cells, presence of the IDR domain changed the dynamics of FBP17 recruitment in a curvature-coupled cortical wave system. Collectively, we propose that FBP17 does sense curvature but contrary to the common belief, its curvature sensing capability largely originates from its disordered region, not F-BAR domain itself.

scholarly journals Dynamic recruitment of the curvature-sensitive protein ArhGAP44 to nanoscale membrane deformations limits exploratory filopodia initiation in neurons

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Milos Galic ◽  
Feng-Chiao Tsai ◽  
Sean R Collins ◽  
Maja Matis ◽  
Samuel Bandara ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Neuronal Development ◽  
Membrane Curvature ◽  
Gtp Hydrolysis ◽  
Bar Domain ◽  
Curvature Sensing ◽  
Contractile Forces ◽  
Dendritic Branches ◽  
Membrane Deformations ◽  
Protein Recruitment

In the vertebrate central nervous system, exploratory filopodia transiently form on dendritic branches to sample the neuronal environment and initiate new trans-neuronal contacts. While much is known about the molecules that control filopodia extension and subsequent maturation into functional synapses, the mechanisms that regulate initiation of these dynamic, actin-rich structures have remained elusive. Here, we find that filopodia initiation is suppressed by recruitment of ArhGAP44 to actin-patches that seed filopodia. Recruitment is mediated by binding of a membrane curvature-sensing ArhGAP44 N-BAR domain to plasma membrane sections that were deformed inward by acto-myosin mediated contractile forces. A GAP domain in ArhGAP44 triggers local Rac-GTP hydrolysis, thus reducing actin polymerization required for filopodia formation. Additionally, ArhGAP44 expression increases during neuronal development, concurrent with a decrease in the rate of filopodia formation. Together, our data reveals a local auto-regulatory mechanism that limits initiation of filopodia via protein recruitment to nanoscale membrane deformations.

scholarly journals Muscle-specific Cavin4 interacts with Bin1 to promote T-tubule formation and stability in developing skeletal muscle

2021 ◽  
Author(s):  
Harriet P. Lo ◽  
Ye-Wheen Lim ◽  
Zherui Xiong ◽  
Nick Martel ◽  
Charles Ferguson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mechanical Stimulation ◽  
Specific Component ◽  
Tubule Formation ◽  
Bar Domain ◽  
T Tubules ◽  
Domain Protein ◽  
And Function

SummaryThe cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems: mouse and zebrafish. In both models Cavin4 localized to T-tubules and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule-associated BAR domain protein, Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function.

scholarly journals Structure and function of yeast Atg20, a sorting nexin that facilitates autophagy induction

2017 ◽  
Vol 114 (47) ◽  
pp. E10112-E10121 ◽  
Author(s):  
Hana Popelka ◽  
Alejandro Damasio ◽  
Jenny E. Hinshaw ◽  
Daniel J. Klionsky ◽  
Michael J. Ragusa
Keyword(s):  
Critical Role ◽  
Amphipathic Helix ◽  
Bar Domain ◽  
Sorting Nexin ◽  
Intrinsically Disordered ◽  
Autophagy Induction ◽  
Efficient Induction ◽  
Bar Domains ◽  
And Function ◽  
Structurally Stable

The Atg20 and Snx4/Atg24 proteins have been identified in a screen for mutants defective in a type of selective macroautophagy/autophagy. Both proteins are connected to the Atg1 kinase complex, which is involved in autophagy initiation, and bind phosphatidylinositol-3-phosphate. Atg20 and Snx4 contain putative BAR domains, suggesting a possible role in membrane deformation, but they have been relatively uncharacterized. Here we demonstrate that, in addition to its function in selective autophagy, Atg20 plays a critical role in the efficient induction of nonselective autophagy. Atg20 is a dynamic posttranslationally modified protein that engages both structurally stable (PX and BAR) and intrinsically disordered domains for its function. In addition to its PX and BAR domains, Atg20 uses a third membrane-binding module, a membrane-inducible amphipathic helix present in a previously undescribed location in Atg20 within the putative BAR domain. Taken together, these findings yield insights into the molecular mechanism of the autophagy machinery.

scholarly journals Mechanism of Membrane Curvature Sensing by Amphipathic Helix Containing Proteins

2011 ◽  
Vol 100 (5) ◽  
pp. 1271-1279 ◽  
Author(s):  
Haosheng Cui ◽  
Edward Lyman ◽  
Gregory A. Voth
Keyword(s):  
Membrane Curvature ◽  
Amphipathic Helix ◽  
Curvature Sensing

scholarly journals The long and short of membrane curvature sensing by septins

2019 ◽  
Vol 218 (4) ◽  
pp. 1083-1085 ◽  
Author(s):  
Michael A. McMurray
Keyword(s):  
Membrane Curvature ◽  
Amphipathic Helix ◽  
Curvature Sensing ◽  
Cell Biol ◽  
Necessary And Sufficient

Septin proteins form hetero-oligomers that associate with membranes of specific curvatures, but the mechanism is unknown. In this issue, Cannon et al. (2019. J. Cell Biol. https://doi.org/10.1083/jcb.201807211) identify a single amphipathic helix that is necessary and sufficient for membrane curvature sensing by septins.

scholarly journals Comparing physical mechanisms for membrane curvature-driven sorting of BAR-domain proteins

Soft Matter ◽  
2021 ◽  
Vol 17 (16) ◽  
pp. 4254-4265
Author(s):  
Feng-Ching Tsai ◽  
Mijo Simunovic ◽  
Benoit Sorre ◽  
Aurélie Bertin ◽  
John Manzi ◽  
...  
Keyword(s):  
Theoretical Models ◽  
Membrane Curvature ◽  
Bar Domain ◽  
Curvature Sensing ◽  
Physical Mechanisms ◽  
Electron Microscopy Data ◽  
Bar Domain Proteins ◽  
Microscopy Data ◽  
Curvature Driven ◽  
Review Current

We review current theoretical models for curvature sensing of BAR-domain proteins, test the models on 2 proteins, and present new electron microscopy data on the organization of BAR domains on tubes.

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