scholarly journals Non-uniform distribution of myosin-mediated forces governs red blood cell membrane curvature through tension modulation

2019 ◽  
Author(s):  
Haleh Alimohamadi ◽  
Alyson S. Smith ◽  
Roberta B. Nowak ◽  
Velia M. Fowler ◽  
Padmini Rangamani
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Contractile Activity ◽  
Cell Types ◽  
Membrane Skeleton ◽  
Membrane Curvature ◽  
Force Density ◽  
Additional Contribution ◽  
Rbc Membrane ◽  
Applied Forces

AbstractThe biconcave disk shape of the mammalian red blood cell (RBC) is unique to the RBC and is vital for its circulatory function. Due to the absence of a transcellular cytoskeleton, RBC shape is determined by the membrane skeleton, a network of actin filaments cross-linked by spectrin and attached to membrane proteins. While the physical properties of a uniformly distributed actin network interacting with the lipid bilayer membrane have been assumed to control RBC shape, recent experiments reveal that RBC biconcave shape also depends on the contractile activity of nonmuscle myosin IIA (NMIIA) motor proteins. Here, we use the classical Helfrich-Canham model for the RBC membrane to test the role of heterogeneous force distributions along the membrane and mimic the contractile activity of sparsely distributed NMIIA filaments. By incorporating this additional contribution to the Helfrich-Canham energy, we find that the RBC biconcave shape depends on the ratio of forces per unit volume in the dimple and rim regions of the RBC. Experimental measurements of NMIIA densities at the dimple and rim validate our prediction that (a) membrane forces must be non-uniform along the RBC membrane and (b) the force density must be larger in the dimple than the rim to produce the observed membrane curvatures. Furthermore, we predict that RBC membrane tension and the orientation of the applied forces play important roles in regulating this force-shape landscape. Our findings of heterogeneous force distributions on the plasma membrane for RBC shape maintenance may also have implications for shape maintenance in different cell types.

scholarly journals Nanoscale organization of Actin Filaments in the Red Blood Cell Membrane Skeleton

2021 ◽  
Author(s):  
Roberta B. Nowak ◽  
Haleh Alimohamadi ◽  
Kersi Pestonjamasp ◽  
Padmini Rangamani ◽  
Velia M. Fowler
Keyword(s):  
Blood Cell ◽  
Single Molecule ◽  
Red Blood Cell ◽  
Synthetic Data ◽  
Membrane Skeleton ◽  
Membrane Curvature ◽  
Data Sets ◽  
Actin Network ◽  
Computational Cluster ◽  
Planar Network

AbstractRed blood cell (RBC) shape and deformability are supported by a planar network of short actin filament (F-actin) nodes interconnected by long spectrin molecules at the inner surface of the plasma membrane. Spectrin-F-actin network structure underlies quantitative modelling of forces controlling RBC shape, membrane curvature and deformation, yet the nanoscale organization of F-actin nodes in the network in situ is not understood. Here, we examined F-actin distribution in RBCs using fluorescent-phalloidin labeling of F-actin imaged by multiple microscopy modalities. Total internal reflection fluorescence (TIRF) and Zeiss Airyscan confocal microscopy demonstrate that F-actin is concentrated in multiple brightly stained F-actin foci ∼200-300 nm apart interspersed with dimmer F-actin staining regions. Live cell imaging reveals dynamic lateral movements, appearance and disappearance of F-actin foci. Single molecule STORM imaging and computational cluster analysis of experimental and synthetic data sets indicate that individual filaments are non-randomly distributed, with the majority as multiple filaments, and the remainder sparsely distributed as single filaments. These data indicate that F-actin nodes are non-uniformly distributed in the spectrin-F-actin network and necessitate reconsideration of current models of forces accounting for RBC shape and membrane deformability, predicated upon uniform distribution of F-actin nodes and associated proteins across the micron-scale RBC membrane.

Nanoscale Dynamics of Actin Filaments in the Red Blood Cell Membrane Skeleton

2022 ◽  
Author(s):  
Roberta B. Nowak ◽  
Haleh Alimohamadi ◽  
Kersi Pestonjamasp ◽  
Padmini Rangamani ◽  
Velia M. Fowler
Keyword(s):  
Blood Cell ◽  
Single Molecule ◽  
Red Blood Cell ◽  
Actin Polymerization ◽  
Network Connectivity ◽  
Membrane Skeleton ◽  
Membrane Curvature ◽  
Actin Network ◽  
Node Distribution ◽  
Planar Network

Red blood cell (RBC) shape and deformability are supported by a planar network of short actin filament (F-actin) nodes (∼37 nm length, 15-18 subunits) interconnected by long spectrin strands at the inner surface of the plasma membrane. Spectrin-F-actin network structure underlies quantitative modeling of forces controlling RBC shape, membrane curvature and deformation, yet the nanoscale organization and dynamics of the F-actin nodes in situ is not well understood. We examined F-actin distribution and dynamics in RBCs using fluorescent-phalloidin labeling of F-actin imaged by multiple microscopy modalities. Total internal reflection fluorescence (TIRF) and Zeiss Airyscan confocal microscopy demonstrate that F-actin is concentrated in multiple brightly stained F-actin foci ∼200-300 nm apart interspersed with dimmer F-actin staining regions. Single molecule STORM imaging of Alexa-647-phalloidin-labeled F-actin and computational analysis also indicates an irregular, non-random distribution of F-actin nodes. Treatment of RBCs with LatA and CytoD indicates F-actin foci distribution depends on actin polymerization, while live cell imaging reveals dynamic local motions of F-actin foci, with lateral movements, appearance and disappearance. Regulation of F-actin node distribution and dynamics via actin assembly/disassembly pathways and/or via local extension and retraction of spectrin strands may provide a new mechanism to control spectrin-F-actin network connectivity, RBC shape and membrane deformability.

scholarly journals Direct Measurement of the Area Expansion and Shear Moduli of the Human Red Blood Cell Membrane Skeleton

2001 ◽  
Vol 81 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Guillaume Lenormand ◽  
Sylvie Hénon ◽  
Alain Richert ◽  
Jacqueline Siméon ◽  
François Gallet
Keyword(s):  
Cell Membrane ◽  
Blood Cell ◽  
Direct Measurement ◽  
Red Blood Cell ◽  
Membrane Skeleton ◽  
Shear Moduli ◽  
Red Blood Cell Membrane ◽  
Area Expansion

scholarly journals Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability

2018 ◽  
Vol 115 (19) ◽  
pp. E4377-E4385 ◽  
Author(s):  
Alyson S. Smith ◽  
Roberta B. Nowak ◽  
Sitong Zhou ◽  
Michael Giannetto ◽  
David S. Gokhin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Motor Activity ◽  
Control Cell ◽  
Cell Types ◽  
Membrane Skeleton ◽  
Membrane Curvature ◽  
General Function ◽  
Actin Networks ◽  
Cell Shapes

The biconcave disk shape and deformability of mammalian RBCs rely on the membrane skeleton, a viscoelastic network of short, membrane-associated actin filaments (F-actin) cross-linked by long, flexible spectrin tetramers. Nonmuscle myosin II (NMII) motors exert force on diverse F-actin networks to control cell shapes, but a function for NMII contractility in the 2D spectrin–F-actin network of RBCs has not been tested. Here, we show that RBCs contain membrane skeleton-associated NMIIA puncta, identified as bipolar filaments by superresolution fluorescence microscopy. MgATP disrupts NMIIA association with the membrane skeleton, consistent with NMIIA motor domains binding to membrane skeleton F-actin and contributing to membrane mechanical properties. In addition, the phosphorylation of the RBC NMIIA heavy and light chains in vivo indicates active regulation of NMIIA motor activity and filament assembly, while reduced heavy chain phosphorylation of membrane skeleton-associated NMIIA indicates assembly of stable filaments at the membrane. Treatment of RBCs with blebbistatin, an inhibitor of NMII motor activity, decreases the number of NMIIA filaments associated with the membrane and enhances local, nanoscale membrane oscillations, suggesting decreased membrane tension. Blebbistatin-treated RBCs also exhibit elongated shapes, loss of membrane curvature, and enhanced deformability, indicating a role for NMIIA contractility in promoting membrane stiffness and maintaining RBC biconcave disk cell shape. As structures similar to the RBC membrane skeleton exist in many metazoan cell types, these data demonstrate a general function for NMII in controlling specialized membrane morphology and mechanical properties through contractile interactions with short F-actin in spectrin–F-actin networks.

scholarly journals Altered Levels of Desaturation and ω-6 Fatty Acids in Breast Cancer Patients’ Red Blood Cell Membranes

Metabolites ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 469
Author(s):  
Javier Amézaga ◽  
Gurutze Ugartemendia ◽  
Aitziber Larraioz ◽  
Nerea Bretaña ◽  
Aizpea Iruretagoyena ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Blood Cell ◽  
Cancer Patients ◽  
Red Blood Cell ◽  
Breast Cancer Patients ◽  
Disease Evolution ◽  
Lipidomic Analysis ◽  
Rbc Membrane

Red blood cell (RBC) membrane can reflect fatty acid (FA) contribution from diet and biosynthesis. In cancer, membrane FAs are involved in tumorigenesis and invasiveness, and are indicated as biomarkers to monitor the disease evolution as well as potential targets for therapies and nutritional strategies. The present study provides RBC membrane FA profiles in recently diagnosed breast cancer patients before starting chemotherapy treatment. Patients and controls were recruited, and their dietary habits were collected. FA lipidomic analysis of mature erythrocyte membrane phospholipids in blood samples was performed. Data were adjusted to correct for the effects of diet, body mass index (BMI), and age, revealing that patients showed lower levels of saturated fatty acids (SFA) and higher levels of monounsaturated fatty acid, cis-vaccenic (25%) than controls, with consequent differences in desaturase enzymatic index (∆9 desaturase, –13.1%). In the case of polyunsaturated fatty acids (PUFA), patients had higher values of ω-6 FA (C18:2 (+11.1%); C20:4 (+7.4%)). RBC membrane lipidomic analysis in breast cancer revealed that ω-6 pathways are favored. These results suggest new potential targets for treatments and better nutritional guidelines.

scholarly journals Contribution of the band 3-ankyrin interaction to erythrocyte membrane mechanical stability

Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1581-1586 ◽  
Author(s):  
PS Low ◽  
BM Willardson ◽  
N Mohandas ◽  
M Rossi ◽  
S Shohet
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Mechanical Stability ◽  
Membrane Integrity ◽  
Membrane Skeleton ◽  
Band 3 ◽  
Cell Membrane Integrity ◽  
The Face ◽  
Cell Stability

Abstract In an effort to evaluate the role of the band 3-ankyrin linkage in maintenance of red blood cell membrane integrity, solution conditions were sought that would selectively dissociate the band 3-ankyrin linkage, leaving other membrane skeletal interactions intact. For this purpose erythrocytes were equilibrated overnight in nutrient-containing buffers at a range of elevated pHs and then examined for changes in mechanical stability and membrane skeletal composition. Band 3 was found to be released from interaction with the membrane skeleton over a pH range (8.4 to 9.5) that was observed to dissociate the band 3- ankyrin interaction in vitro. In contrast, all other membrane skeletal associations appeared to remain intact up to pH 9.3, after which they were also seen to dissociate. Whereas hemolysis of mechanically unstressed cells did not begin until approximately pH 9.3, where the membrane skeletons began to disintegrate, enhanced fragmentation of shear stressed membranes was seen to begin near pH 8, where band 3 dissociation was first observed. Furthermore, the shear-induced fragmentation rate was found to reach a maximum at pH 9.4, ie, where band 3 dissociation was essentially complete. Based on these correlations, we hypothesize that the band 3-ankyrin linkage of the membrane skeleton to the lipid bilayer is essential for red blood cell stability in the face of mechanical distortion but not for cellular integrity in the absence of mechanical stress.

Red blood cell (RBC) age at collection and storage influences RBC membrane-associated carbohydrates and lectin binding

Transfusion ◽  
2007 ◽  
Vol 47 (6) ◽  
pp. 966-968 ◽  
Author(s):  
Rosemary L. Sparrow ◽  
Margaret F. Veale ◽  
Geraldine Healey ◽  
Katherine A. Payne
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Lectin Binding ◽  
Rbc Membrane ◽  
And Storage
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