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 Fission of SNX-BAR–coated endosomal retrograde transport carriers is promoted by the dynamin-related protein Vps1

2014 ◽  
Vol 204 (5) ◽  
pp. 793-806 ◽  
Author(s):  
Richard J. Chi ◽  
Jingxuan Liu ◽  
Matthew West ◽  
Jing Wang ◽  
Greg Odorizzi ◽  
...  
Keyword(s):  
Retrograde Transport ◽  
Related Protein ◽  
Membrane Remodeling ◽  
Functional Link ◽  
Bar Domain ◽  
Endosomal Sorting ◽  
Sorting Nexin ◽  
Bar Domain Proteins

Retromer is an endosomal sorting device that orchestrates capture and packaging of cargo into transport carriers coated with sorting nexin BAR domain proteins (SNX-BARs). We report that fission of retromer SNX-BAR–coated tubules from yeast endosomes is promoted by Vps1, a dynamin-related protein that localizes to endosomes decorated by retromer SNX-BARs and Mvp1, a SNX-BAR that is homologous to human SNX8. Mvp1 exhibits potent membrane remodeling activity in vitro, and it promotes association of Vps1 with the endosome in vivo. Retrograde transport carriers bud from the endosome coated by retromer and Mvp1, and cargo export is deficient in mvp1- and vps1-null cells, but with distinct endpoints; cargo export is delayed in mvp1-null cells, but cargo export completely fails in vps1-null cells. The results indicate that Mvp1 promotes Vps1-mediated fission of retromer- and Mvp1-coated tubules that bud from the endosome, revealing a functional link between the endosomal sorting and fission machineries to produce retrograde transport carriers.

scholarly journals Ezrin enrichment on curved membranes requires a specific conformation or interaction with a curvature-sensitive partner

2018 ◽  
Author(s):  
Feng-Ching Tsai ◽  
Aurélie Bertin ◽  
Hugo Bousquet ◽  
John Manzi ◽  
Yosuke Senju ◽  
...  
Keyword(s):  
Cell Biology ◽  
Membrane Curvature ◽  
Bar Domain ◽  
Negatively Curved ◽  
Current Cell ◽  
Bar Domain Proteins ◽  
Membrane Protrusions ◽  
Curved Membranes ◽  
Curved Membrane

AbstractOne challenge in current cell biology is to decipher the biophysical mechanisms governing protein enrichment on curved membranes and the resulting membrane deformation. The ERM protein ezrin is abundant and associated with cellular membranes that are flat or with positive or negative curvatures. Using in vitro and cell biology approaches, we assess mechanisms of ezrin’s enrichment on curved membranes. We evidence that ezrin (ezrinWT) and its phosphomimetic mutant T567D (ezrinTD) do not deform membranes but self-assemble anti-parallelly, zipping adjacent membranes. EzrinTD’s specific conformation reduces intermolecular ezrin interactions, allows binding to actin filaments, and promotes ezrin binding to positively curved membranes. While neither ezrinTD nor ezrinWT senses negative membrane curvature alone, we demonstrate that interacting with curvature sensors I-BAR-domain proteins facilitates ezrin enrichment in negatively curved membrane protrusions. Overall, our work reveals new mechanisms, specific conformation or binding to a curvature sensor partner, for targeting curvature insensitive proteins to curved membranes.

The Role of BAR Domain Proteins in the Regulation of Membrane Dynamics

Acta Naturae ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 60-69 ◽  
Author(s):  
T. B. Stanishneva-Konovalova ◽  
N. I Derkacheva ◽  
S. V. Polevova ◽  
O. S. Sokolova
Keyword(s):  
Membrane Dynamics ◽  
Actin Dynamics ◽  
Membrane Remodeling ◽  
Bar Domain ◽  
Cellular Processes ◽  
Functional Differences ◽  
Bar Domain Proteins ◽  
Domain Protein ◽  
Bar Domains

Many cellular processes are associated with membrane remodeling. The BAR domain protein family plays a key role in the formation and detection of local membrane curvatures and in attracting other proteins, including the regulators of actin dynamics. Based on their structural and phylogenetic properties, BAR domains are divided into several groups which affect membrane in various ways and perform different functions in cells. However, recent studies have uncovered evidence of functional differences even within the same group. This review discusses the principles underlying the interactions of different groups of BAR domains, and their individual representatives, with membranes.

scholarly journals Single-molecule imaging of the BAR-domain protein Pil1p reveals filament-end dynamics

2017 ◽  
Vol 28 (17) ◽  
pp. 2251-2259 ◽  
Author(s):  
Michael M. Lacy ◽  
David Baddeley ◽  
Julien Berro
Keyword(s):  
Single Molecule ◽  
Nanometer Scale ◽  
Bar Domain ◽  
Physiological Conditions ◽  
Macromolecular Assemblies ◽  
Cytoplasmic Face ◽  
Bar Domain Proteins ◽  
Domain Protein

Molecular assemblies can have highly heterogeneous dynamics within the cell, but the limitations of conventional fluorescence microscopy can mask nanometer-scale features. Here we adapt a single-molecule strategy to perform single-molecule recovery after photobleaching (SRAP) within dense macromolecular assemblies to reveal and characterize binding and unbinding dynamics within such assemblies. We applied this method to study the eisosome, a stable assembly of BAR-domain proteins on the cytoplasmic face of the plasma membrane in fungi. By fluorescently labeling only a small fraction of cellular Pil1p, the main eisosome BAR-domain protein in fission yeast, we visualized whole eisosomes and, after photobleaching, localized recruitment of new Pil1p molecules with ∼30-nm precision. Comparing our data to computer simulations, we show that Pil1p exchange occurs specifically at eisosome ends and not along their core, supporting a new model of the eisosome as a dynamic filament. This result is the first direct observation of any BAR-domain protein dynamics in vivo under physiological conditions consistent with the oligomeric filaments reported from in vitro experiments.

scholarly journals When the Balance Tips: Dysregulation of Mitochondrial Dynamics as a Culprit in Disease

2021 ◽  
Vol 22 (9) ◽  
pp. 4617
Author(s):  
Styliana Kyriakoudi ◽  
Anthi Drousiotou ◽  
Petros P. Petrou
Keyword(s):  
Insulin Resistance ◽  
Mitochondrial Function ◽  
Human Disease ◽  
Molecular Mechanisms ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fusion ◽  
Mitochondrial Morphology ◽  
Disease Development ◽  
Pathological Conditions ◽  
Wide Range

Mitochondria are dynamic organelles, the morphology of which is tightly linked to their functions. The interplay between the coordinated events of fusion and fission that are collectively described as mitochondrial dynamics regulates mitochondrial morphology and adjusts mitochondrial function. Over the last few years, accruing evidence established a connection between dysregulated mitochondrial dynamics and disease development and progression. Defects in key components of the machinery mediating mitochondrial fusion and fission have been linked to a wide range of pathological conditions, such as insulin resistance and obesity, neurodegenerative diseases and cancer. Here, we provide an update on the molecular mechanisms promoting mitochondrial fusion and fission in mammals and discuss the emerging association of disturbed mitochondrial dynamics with human disease.

scholarly journals Intraperitoneal Triamcinolone Reduces Postoperative Adhesions, Possibly through Alteration of Mitochondrial Function

2022 ◽  
Vol 11 (2) ◽  
pp. 301
Author(s):  
Neeraja Purandare ◽  
Katherine J. Kramer ◽  
Paige Minchella ◽  
Sarah Ottum ◽  
Christopher Walker ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Mitochondrial Function ◽  
Molecular Mechanisms ◽  
Human Fibroblasts ◽  
Reactive Oxygen ◽  
Retrospective Chart Review ◽  
Oxygen Species ◽  
Abdominal Myomectomy ◽  
Hypoxic Conditions

Adhesions frequently occur postoperatively, causing morbidity. In this noninterventional observational cohort study, we enrolled patients who presented for repeat abdominal surgery, after a history of previous abdominal myomectomy, from March 1998 to June 20210 at St. Vincent’s Catholic Medical Centers. The primary outcome of this pilot study was to compare adhesion rates, extent, and severity in patients who were treated with intraperitoneal triamcinolone acetonide during the initial abdominal myomectomy (n = 31) with those who did not receive any antiadhesion interventions (n = 21), as documented on retrospective chart review. Adhesions were blindly scored using a standard scoring system. About 32% of patients were found to have adhesions in the triamcinolone group compared to 71% in the untreated group (p < 0.01). Compared to controls, adhesions were significantly less in number (0.71 vs. 2.09, p < 0.005), severity (0.54 vs. 1.38, p < 0.004), and extent (0.45 vs. 1.28, p < 0.003). To understand the molecular mechanisms, human fibroblasts were incubated in hypoxic conditions and treated with triamcinolone or vehicle. In vitro studies showed that triamcinolone directly prevents the surge of reactive oxygen species triggered by 2% hypoxia and prevents the increase in TGF-β1 that leads to the irreversible conversion of fibroblasts to an adhesion phenotype. Triamcinolone prevents the increase in reactive oxygen species through alterations in mitochondrial function that are HIF-1α-independent. Controlling mitochondrial function may thus allow for adhesion-free surgery and reduced postoperative complications.

scholarly journals Light-Inducible Generation of Membrane Curvature in Live Cells with Engineered BAR Domain Proteins

2020 ◽  
Vol 9 (4) ◽  
pp. 893-901
Author(s):  
Taylor Jones ◽  
Aofei Liu ◽  
Bianxiao Cui
Keyword(s):  
Membrane Curvature ◽  
Live Cells ◽  
Bar Domain ◽  
Bar Domain Proteins

scholarly journals Bar Domain Proteins can Differ Substantially in their Capacity to Generate Membrane Curvature

2016 ◽  
Vol 110 (3) ◽  
pp. 357a
Author(s):  
Zhiming Chen ◽  
Zheng Shi ◽  
Katarzyna I. Jankowska ◽  
Tobias Baumgart
Keyword(s):  
Membrane Curvature ◽  
Bar Domain ◽  
Bar Domain Proteins

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.

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