Glycolipid-Enriched Membrane Domains Are Assembled into Membrane Patches by Associating with the Actin Cytoskeleton

2001 ◽  
Vol 267 (2) ◽  
pp. 173-183 ◽  
Author(s):  
William Rodgers ◽  
Joelle Zavzavadjian
Keyword(s):  
Actin Cytoskeleton ◽  
Membrane Domains

scholarly journals Massive calcium–activated endocytosis without involvement of classical endocytic proteins

2010 ◽  
Vol 137 (1) ◽  
pp. 111-132 ◽  
Author(s):  
Vincenzo Lariccia ◽  
Michael Fine ◽  
Simona Magi ◽  
Mei-Jung Lin ◽  
Alp Yaradanakul ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Cardiac Myocytes ◽  
Adenosine Triphosphate ◽  
Hek293 Cells ◽  
Membrane Domains ◽  
Baby Hamster Kidney ◽  
Bromoenol Lactone ◽  
Cytoplasmic Side

We describe rapid massive endocytosis (MEND) of >50% of the plasmalemma in baby hamster kidney (BHK) and HEK293 cells in response to large Ca transients. Constitutively expressed Na/Ca exchangers (NCX1) are used to generate Ca transients, whereas capacitance recording and a membrane tracer dye, FM 4–64, are used to monitor endocytosis. With high cytoplasmic adenosine triphosphate (ATP; >5 mM), Ca influx causes exocytosis followed by MEND. Without ATP, Ca transients cause only exocytosis. MEND can then be initiated by pipette perfusion of ATP, and multiple results indicate that ATP acts via phosphatidylinositol-bis 4,5-phosphate (PIP2) synthesis: PIP2 substitutes for ATP to induce MEND. ATP-activated MEND is blocked by an inositol 5-phosphatase and by guanosine 5′-[γ-thio]triphosphate (GTPγS). Block by GTPγS is overcome by the phospholipase C inhibitor, U73122, and PIP2 induces MEND in the presence of GTPγS. MEND can occur in the absence of ATP and PIP2 when cytoplasmic free Ca is clamped to 10 µM or more by Ca-buffered solutions. ATP-independent MEND occurs within seconds during Ca transients when cytoplasmic solutions contain polyamines (e.g., spermidine) or the membrane is enriched in cholesterol. Although PIP2 and cholesterol can induce MEND minutes after Ca transients have subsided, polyamines must be present during Ca transients. MEND can reverse over minutes in an ATP-dependent fashion. It is blocked by brief β-methylcyclodextrin treatments, and tests for involvement of clathrin, dynamins, calcineurin, and actin cytoskeleton were negative. Therefore, we turned to the roles of lipids. Bacterial sphingomyelinases (SMases) cause similar MEND responses within seconds, suggesting that ceramide may be important. However, Ca-activated MEND is not blocked by reagents that inhibit SMases. MEND is abolished by the alkylating phospholipase A2 inhibitor, bromoenol lactone, whereas exocytosis remains robust, and Ca influx causes MEND in cardiac myocytes without preceding exocytosis. Thus, exocytosis is not prerequisite for MEND. From these results and two companion studies, we suggest that Ca promotes the formation of membrane domains that spontaneously vesiculate to the cytoplasmic side.

scholarly journals Identification of Filamin as a Novel Ligand for Caveolin-1: Evidence for the Organization of Caveolin-1–associated Membrane Domains by the Actin Cytoskeleton

2000 ◽  
Vol 11 (1) ◽  
pp. 325-337 ◽  
Author(s):  
Martin Stahlhut ◽  
Bo van Deurs
Keyword(s):  
Actin Cytoskeleton ◽  
Spatial Organization ◽  
Hybrid Approach ◽  
Fiber Formation ◽  
Membrane Domains ◽  
Dimerization Domain ◽  
Double Labeling ◽  
Caveolin 1 ◽  
C Terminus

Reports on the ultrastructure of cells as well as biochemical data have, for several years, been indicating a connection between caveolae and the actin cytoskeleton. Here, using a yeast two-hybrid approach, we have identified the F-actin cross-linking protein filamin as a ligand for the caveolae-associated protein caveolin-1. Binding of caveolin-1 to filamin involved the N-terminal region of caveolin-1 and the C terminus of filamin close to the filamin-dimerization domain. In in vitro binding assays, recombinant caveolin-1 bound to both nonmuscle and muscle filamin, indicating that the interaction might not be cell type specific. With the use of confocal microscopy, colocalization of caveolin-1 and filamin was observed in elongated patches at the plasma membrane. Remarkably, when stress fiber formation was induced with Rho-stimulating Escherichia coli cytotoxic necrotizing factor 1, the caveolin-1–positive structures became coaligned with stress fibers, indicating that there was a physical link connecting them. Immunogold double-labeling electron microscopy confirmed that caveolin-1–labeled racemose caveolae clusters were positive for filamin. The actin network, therefore, seems to be directly involved in the spatial organization of caveolin-1–associated membrane domains.

Cytoskeletal interactions regulate inducible L-selectin clustering

2005 ◽  
Vol 289 (2) ◽  
pp. C323-C332 ◽  
Author(s):  
Polly E. Mattila ◽  
Chad E. Green ◽  
Ulrich Schaff ◽  
Scott I. Simon ◽  
Bruce Walcheck
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Transmembrane Protein ◽  
Membrane Domains ◽  
Membrane Domain ◽  
Lateral Mobility ◽  
Progressive Change ◽  
Glycosyl Phosphatidylinositol ◽  
Effector Functions ◽  
G Protein Coupled

L-selectin (CD62L) amplifies neutrophil capture within the microvasculature at sites of inflammation. Activation by G protein-coupled stimuli or through ligation of L-selectin promotes clustering of L-selectin and serves to increase its adhesiveness, signaling, and colocalization with β2-integrins. Currently, little is known about the molecular process regulating the lateral mobility of L-selectin. On neutrophil stimulation, a progressive change takes place in the organization of its plasma membrane, resulting in membrane domains that are characteristically enriched in glycosyl phosphatidylinositol (GPI)-anchored proteins and exclude the transmembrane protein CD45. Clustering of L-selectin, facilitated by E-selectin engagement or antibody cross-linking, resulted in its colocalization with GPI-anchored CD55, but not with CD45 or CD11c. Disrupting microfilaments in neutrophils or removing a conserved cationic motif in the cytoplasmic domain of L-selectin increased its mobility and membrane domain localization in the plasma membrane. In addition, the conserved element was critical for L-selectin-dependent tethering under shear flow. Our data indicate that L-selectin’s lateral mobility is regulated by interactions with the actin cytoskeleton that in turn fortifies leukocyte tethering. We hypothesize that both membrane mobility and stabilization augment L-selectin’s effector functions and are regulated by dynamic associations with membrane domains and the actin cytoskeleton.

On the assembly and structural modulation of lens fiber junctions

1984 ◽  
Vol 42 ◽  
pp. 110-113
Author(s):  
E.L. Benedetti ◽  
I. Dunia ◽  
Do Ngoc Lien ◽  
O. Vallon ◽  
D. Louvard ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Natural History ◽  
Intercellular Junctions ◽  
Eye Lens ◽  
Membrane Domains ◽  
Functional Polymorphism ◽  
Lens Fiber ◽  
The Past ◽  
Structural Modulation ◽  
Biochemical Difference

In the eye lens emerging molecular and structural patterns apparently cohabit with the remnants of the past. The lens in a rather puzzling fashion sums up its own natural history and even transient steps of the differentiation are memorized. A prototype of this situation is well outlined by the study of the lenticular intercellular junctions. These membrane domains exhibit structural, biochemical and perhaps functional polymorphism reflecting throughout life the multiple steps of the differentiation of the epithelium into fibers and of the ageing process of the lenticular cells.The most striking biochemical difference between the membrane derived from the epithelium and from the fibers respectively, concerns the presence of the 26,000 molecular weight polypeptide (MP26) in the latter membranes.

Membrane microdomains: lessons from microscopy

1995 ◽  
Vol 53 ◽  
pp. 776-777
Author(s):  
J.M. Robinson ◽  
J.M Oliver
Keyword(s):  
Spatial Distribution ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Plasma Membranes ◽  
Cell Types ◽  
Imaging Modalities ◽  
Membrane Microdomains ◽  
Membrane Domains ◽  
Lateral Heterogeneity ◽  
Functional Importance

Specialized regions of plasma membranes displaying lateral heterogeneity are the focus of this Symposium. Specialized membrane domains are known for certain cell types such as differentiated epithelial cells where lateral heterogeneity in lipids and proteins exists between the apical and basolateral portions of the plasma membrane. Lateral heterogeneity and the presence of microdomains in membranes that are uniform in appearance have been more difficult to establish. Nonetheless a number of studies have provided evidence for membrane microdomains and indicated a functional importance for these structures.This symposium will focus on the use of various imaging modalities and related approaches to define membrane microdomains in a number of cell types. The importance of existing as well as emerging imaging technologies for use in the elucidation of membrane microdomains will be highlighted. The organization of membrane microdomains in terms of dimensions and spatial distribution is of considerable interest and will be addressed in this Symposium.

The organization of cell surface membrane domains

1989 ◽  
Vol 47 ◽  
pp. 804-805
Author(s):  
Michael Edidin
Keyword(s):  
Cell Surface ◽  
Membrane Lipids ◽  
Surface Membrane ◽  
Lateral Diffusion ◽  
Cell Types ◽  
Membrane Domains ◽  
Membrane Biology ◽  
Morphological Polarity ◽  
Discrete Domains ◽  
Membrane Components

Cell surface membranes are based on a fluid lipid bilayer and models of the membranes' organization have emphasised the possibilities for lateral motion of membrane lipids and proteins within the bilayer. Two recent trends in cell and membrane biology make us consider ways in which membrane organization works against its inherent fluidity, localizing both lipids and proteins into discrete domains. There is evidence for such domains, even in cells without obvious morphological polarity and organization [Table 1]. Cells that are morphologically polarised, for example epithelial cells, raise the issue of membrane domains in an accute form.The technique of fluorescence photobleaching and recovery, FPR, was developed to measure lateral diffusion of membrane components. It has also proven to be a powerful tool for the analysis of constraints to lateral mobility. FPR resolves several sorts of membrane domains, all on the micrometer scale, in several different cell types.

A role for the actin cytoskeleton in the hormonal and growth-factor-mediated activation of protein kinase B

2001 ◽  
Vol 353 (3) ◽  
pp. 735
Author(s):  
K. PEYROLLIER ◽  
E. HAJDUCH ◽  
A. GRAY ◽  
G. J. LITHERLAND ◽  
A. R. PRESCOTT ◽  
...  
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Actin Cytoskeleton ◽  
Protein Kinase B

Membrane–cytoskeleton interactions in cholesterol-dependent domain formation

2015 ◽  
Vol 57 ◽  
pp. 177-187 ◽  
Author(s):  
Jennifer N. Byrum ◽  
William Rodgers
Keyword(s):  
Biological Properties ◽  
Membrane Rafts ◽  
Membrane Domains ◽  
Biological Functions ◽  
Membrane Cytoskeleton ◽  
Heterogeneous Structures ◽  
Integral Role ◽  
Model Cell ◽  
Actomyosin Cytoskeleton ◽  
Dependent Domain

Since the inception of the fluid mosaic model, cell membranes have come to be recognized as heterogeneous structures composed of discrete protein and lipid domains of various dimensions and biological functions. The structural and biological properties of membrane domains are represented by CDM (cholesterol-dependent membrane) domains, frequently referred to as membrane ‘rafts’. Biological functions attributed to CDMs include signal transduction. In T-cells, CDMs function in the regulation of the Src family kinase Lck (p56lck) by sequestering Lck from its activator CD45. Despite evidence of discrete CDM domains with specific functions, the mechanism by which they form and are maintained within a fluid and dynamic lipid bilayer is not completely understood. In the present chapter, we discuss recent advances showing that the actomyosin cytoskeleton has an integral role in the formation of CDM domains. Using Lck as a model, we also discuss recent findings regarding cytoskeleton-dependent CDM domain functions in protein regulation.

Spatial control of actin-based motility through plasmalemmal PtdIns(4,5)P2-rich raft assemblies.

2005 ◽  
Vol 72 ◽  
pp. 119-127 ◽  
Author(s):  
Tamara Golub ◽  
Caroni Pico
Keyword(s):  
Protein Kinase ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Lipid Rafts ◽  
Patch Clustering ◽  
Pkc Protein Kinase C ◽  
Membrane Bound ◽  
And Function ◽  
Cytoskeleton Dynamics ◽  
Syndrome Protein

The interactions of cells with their environment involve regulated actin-based motility at defined positions along the cell surface. Sphingolipid- and cholesterol-dependent microdomains (rafts) order proteins at biological membranes, and have been implicated in most signalling processes at the cell surface. Many membrane-bound components that regulate actin cytoskeleton dynamics and cell-surface motility associate with PtdIns(4,5)P2-rich lipid rafts. Although raft integrity is not required for substrate-directed cell spreading, or to initiate signalling for motility, it is a prerequisite for sustained and organized motility. Plasmalemmal rafts redistribute rapidly in response to signals, triggering motility. This process involves the removal of rafts from sites that are not interacting with the substrate, apparently through endocytosis, and a local accumulation at sites of integrin-mediated substrate interactions. PtdIns(4,5)P2-rich lipid rafts can assemble into patches in a process depending on PtdIns(4,5)P2, Cdc42 (cell-division control 42), N-WASP (neural Wiskott-Aldrich syndrome protein) and actin cytoskeleton dynamics. The raft patches are sites of signal-induced actin assembly, and their accumulation locally promotes sustained motility. The patches capture microtubules, which promote patch clustering through PKA (protein kinase A), to steer motility. Raft accumulation at the cell surface, and its coupling to motility are influenced greatly by the expression of intrinsic raft-associated components that associate with the cytosolic leaflet of lipid rafts. Among them, GAP43 (growth-associated protein 43)-like proteins interact with PtdIns(4,5)P2 in a Ca2+/calmodulin and PKC (protein kinase C)-regulated manner, and function as intrinsic determinants of motility and anatomical plasticity. Plasmalemmal PtdIns(4,5)P2-rich raft assemblies thus provide powerful organizational principles for tight spatial and temporal control of signalling in motility.

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