Inward tubulation of the plasma membrane expedites membrane exchange and receptor presentation

AbstractThe plasma membrane is a crucial barrier between the cell and its external environment, and it also enables efficient passage of materials and information. Membrane vesicle trafficking allows precise delivery of materials but is rather inefficient. The mechanism for efficient membrane exchange remains elusive. Here we describe inward tubulation of the plasma membrane (PM tubes) that extends deep into the cytoplasm. These widespread PM tubes elongate along microtubules and are stabilized by actin filaments and cholesterol. PM tubes are preferred sites for connection between the endoplasmic reticulum and the plasma membrane. PM tubes facilitate receptor presentation at the surface of cells, possibly also shortening the distance for transported cargo to reach the external environment.In BriefA new type of tubular membrane structures was discovered in cells, revealing a shortcut that cells employ to expedite material exchange with their external environment.HighlightsInward tubulation of the plasma membrane (PM tubes), transiently interacts with the Golgi apparatusMicrotubule side-binding proteins pull PM tubes, while actin filaments and cholesterol stabilize PM tubesPM tubes are preferred sites where ER-PM contacts form in response to increased cytoplasmic calcium concentrationPM tubes are preferred sites for the surface presentation of GLUT1 upon glucose deprivation

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Microanatomy of the Periplasm of Bacillus Licheniformis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065365 ◽

1971 ◽

Vol 29 ◽

pp. 262-263

Author(s):

B.K. Ghosh

Keyword(s):

Cell Wall ◽

Plasma Membrane ◽

Bacillus Licheniformis ◽

External Environment ◽

Permeability Barrier ◽

Periplasmic Space ◽

Modified Technique ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

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Actin-membrane interaction in fibroblasts: what proteins are involved in this association?

The Journal of Cell Biology ◽

10.1083/jcb.99.1.95s ◽

1984 ◽

Vol 99 (1) ◽

pp. 95s-103s ◽

Cited By ~ 57

Author(s):

P Mangeat ◽

K Burridge

Keyword(s):

Plasma Membrane ◽

Actin Filaments ◽

Stress Fiber ◽

Membrane Interaction ◽

Microfilament Bundles ◽

The Family ◽

Form Part ◽

Membrane Attachment ◽

A Chain ◽

And Function

In this review we discuss some of the proteins for which a role in linking actin to the fibroblast plasma membrane has been suggested. We focus on the family of proteins related to erythrocyte spectrin, proteins that have generally been viewed as having an organization and a function in actin-membrane attachment similar to those of erythrocyte spectrin. Experiments in which we precipitated the nonerythrocyte spectrin within living fibroblasts have led us to question this supposed similarity of organization and function of the nonerythrocyte and erythrocyte spectrins. Intracellular precipitation of fibroblast spectrin does not affect the integrity of the major actin-containing structures, the stress fiber microfilament bundles. Unexpectedly, however, we found that the precipitation of spectrin results in a condensation and altered distribution of the vimentin class of intermediate filaments in most cells examined. Although fibroblast spectrin may have a role in the attachment of some of the cortical, submembranous actin, it is surprising how little the intracellular immunoprecipitation of the spectrin affects the cells. Several proteins have been found concentrated at the ends of stress fibers, where the actin filaments terminate at focal contacts. Two of these proteins, alpha-actinin and fimbrin, have properties that suggest that they are not involved in the attachment of the ends of the bundles to the membrane but are more probably involved in the organization and cross-linking of the filaments within the bundles. On the other hand, vinculin and talin are two proteins that interact with each other and may form part of a chain of attachments between the ends of the microfilament bundles and the focal contact membrane. Their role in this attachment, however, has not been established and further work is needed to examine their interaction with actin and to identify any other components with which they may interact, particularly in the plasma membrane.

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Two Sides of the Coin: Ezrin/Radixin/Moesin and Merlin Control Membrane Structure and Contact Inhibition

International Journal of Molecular Sciences ◽

10.3390/ijms20081996 ◽

2019 ◽

Vol 20 (8) ◽

pp. 1996 ◽

Cited By ~ 13

Author(s):

Katharine A. Michie ◽

Adam Bermeister ◽

Neil O. Robertson ◽

Sophia C. Goodchild ◽

Paul M. G. Curmi

Keyword(s):

Actin Cytoskeleton ◽

Protein Complexes ◽

Membrane Vesicle ◽

Contact Inhibition ◽

Cell Junctions ◽

Cellular Membranes ◽

Membrane Structures ◽

Cortical Actin ◽

Erm Proteins ◽

Structural Conservation

The merlin-ERM (ezrin, radixin, moesin) family of proteins plays a central role in linking the cellular membranes to the cortical actin cytoskeleton. Merlin regulates contact inhibition and is an integral part of cell–cell junctions, while ERM proteins, ezrin, radixin and moesin, assist in the formation and maintenance of specialized plasma membrane structures and membrane vesicle structures. These two protein families share a common evolutionary history, having arisen and separated via gene duplication near the origin of metazoa. During approximately 0.5 billion years of evolution, the merlin and ERM family proteins have maintained both sequence and structural conservation to an extraordinary level. Comparing crystal structures of merlin-ERM proteins and their complexes, a picture emerges of the merlin-ERM proteins acting as switchable interaction hubs, assembling protein complexes on cellular membranes and linking them to the actin cytoskeleton. Given the high level of structural conservation between the merlin and ERM family proteins we speculate that they may function together.

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The polymerization of actin: II. how nonfilamentous actin becomes nonrandomly distributed in sperm: evidence for the association of this actin with membranes

The Journal of Cell Biology ◽

10.1083/jcb.69.1.51 ◽

1976 ◽

Vol 69 (1) ◽

pp. 51-72 ◽

Cited By ~ 67

Author(s):

LG Tilney

Keyword(s):

Plasma Membrane ◽

Nuclear Envelope ◽

Thin Section ◽

Actin Filaments ◽

Early Stage ◽

Mature Sperm ◽

Vacuole Membrane ◽

Other Substances ◽

Associated Proteins ◽

Basal Half

At an early stage in spermiogenesis the acrosomal vacuole and other organelles including ribosomes are located at the basal end of the cell. From here actin must be transported to its future location at the anterior end of the cell. At no stage in the accumulation of actin in the periacrosomal region is the actin sequestered in a membrane-bounded compartment such as a vacuole or vesicle. Since filaments are not present in the periacrosomal region during the accumulation of the actin even though the fixation of these cells is sufficiently good to distinguish actin filaments in thin section, the actin must accumulate in the nonfilamentous state. The membranes in the periacrosomal region, specifically a portion of the nuclear envelope and the basal half of the acrosomal vacuole membrane, become specialized morphologically in advance of the accumulation of actin in this region. My working hypothesis is that the actin in combination with other substances binds to these specialized membranes and to itself and thus can accumulate in the periacrosmoal region by being trapped on these specialized membranes. Diffusion would then be sufficient to move these substances to this region. In support of this hypothesis are experiments in which I treated mature sperm with detergents, glycols, and hypotonic media, which solubilize or lift away the plasma membrane. The actin and its associated proteins remain attached to these specialized membranes. Thus actin can be nonrandomly distributed in cells in a nonfilamentous state presumably by its association with specialized membranes.

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pH-dependent Cargo Sorting from the Golgi

Journal of Biological Chemistry ◽

10.1074/jbc.m110.197889 ◽

2011 ◽

Vol 286 (12) ◽

pp. 10058-10065 ◽

Cited By ~ 34

Author(s):

Chunjuan Huang ◽

Amy Chang

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Atpase Activity ◽

Secretory Pathway ◽

Ph Dependence ◽

Glucose Deprivation ◽

Ph Homeostasis ◽

Plasma Membrane Proteins ◽

Cytosolic Ph ◽

Cargo Sorting

The vacuolar proton-translocating ATPase (V-ATPase) plays a major role in organelle acidification and works together with other ion transporters to maintain pH homeostasis in eukaryotic cells. We analyzed a requirement for V-ATPase activity in protein trafficking in the yeast secretory pathway. Deficiency of V-ATPase activity caused by subunit deletion or glucose deprivation results in missorting of newly synthesized plasma membrane proteins Pma1 and Can1 directly from the Golgi to the vacuole. Vacuolar mislocalization of Pma1 is dependent on Gga adaptors although no Pma1 ubiquitination was detected. Proper cell surface targeting of Pma1 was rescued in V-ATPase-deficient cells by increasing the pH of the medium, suggesting that missorting is the result of aberrant cytosolic pH. In addition to mislocalization of the plasma membrane proteins, Golgi membrane proteins Kex2 and Vrg4 are also missorted to the vacuole upon loss of V-ATPase activity. Because the missorted cargos have distinct trafficking routes, we suggest a pH dependence for multiple cargo sorting events at the Golgi.

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2SH1035 Dynamics of actin filaments for subcellular membrane structures(2SH Actin as a Cytomotive Filament,The 48th Annual Meeting of the Biophysical Society of Japan)

Seibutsu Butsuri ◽

10.2142/biophys.50.s16_6 ◽

2010 ◽

Vol 50 (supplement2) ◽

pp. S16

Author(s):

Shiro Suetsugu

Keyword(s):

Annual Meeting ◽

Actin Filaments ◽

Membrane Structures ◽

Subcellular Membrane ◽

Biophysical Society

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Barrier role of actin filaments in regulated mucin secretion from airway goblet cells

AJP Cell Physiology ◽

10.1152/ajpcell.00397.2004 ◽

2005 ◽

Vol 288 (1) ◽

pp. C46-C56 ◽

Cited By ~ 50

Author(s):

Camille Ehre ◽

Andrea H. Rossi ◽

Lubna H. Abdullah ◽

Kathleen De Pestel ◽

Sandra Hill ◽

...

Keyword(s):

Plasma Membrane ◽

Actin Filaments ◽

Fluorescent Protein ◽

Secretory Granules ◽

Yellow Fluorescent Protein ◽

Goblet Cells ◽

Actin Binding ◽

Secretory Cells ◽

Cortical Actin ◽

Mucin Secretion

Airway goblet cells secrete mucin onto mucosal surfaces under the regulation of an apical, phospholipase C/Gq-coupled P2Y2receptor. We tested whether cortical actin filaments negatively regulate exocytosis in goblet cells by forming a barrier between secretory granules and plasma membrane docking sites as postulated for other secretory cells. Immunostaining of human lung tissues and SPOC1 cells (an epithelial, mucin-secreting cell line) revealed an apical distribution of β- and γ-actin in ciliated and goblet cells. In goblet cells, actin appeared as a prominent subplasmalemmal sheet lying between granules and the apical membrane, and it disappeared from SPOC1 cells activated by purinergic agonist. Disruption of actin filaments with latrunculin A stimulated SPOC1 cell mucin secretion under basal and agonist-activated conditions, whereas stabilization with jasplakinolide or overexpression of β- or γ-actin conjugated to yellow fluorescent protein (YFP) inhibited secretion. Myristoylated alanine-rich C kinase substrate, a PKC-activated actin-plasma membrane tethering protein, was phosphorylated after agonist stimulation, suggesting a translocation to the cytosol. Scinderin (or adseverin), a Ca2+-activated actin filament severing and capping protein was cloned from human airway and SPOC1 cells, and synthetic peptides corresponding to its actin-binding domains inhibited mucin secretion. We conclude that actin filaments negatively regulate mucin secretion basally in airway goblet cells and are dynamically remodeled in agonist-stimulated cells to promote exocytosis.

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Brush border myosin-I microinjected into cultured cells is targeted to actin-containing surface structures

Journal of Cell Science ◽

10.1242/jcs.107.6.1623 ◽

1994 ◽

Vol 107 (6) ◽

pp. 1623-1631 ◽

Cited By ~ 3

Author(s):

M. Footer ◽

A. Bretscher

Keyword(s):

Plasma Membrane ◽

Brush Border ◽

Actin Filaments ◽

Cultured Cells ◽

Surface Structures ◽

Specific Expression ◽

Cultured Fibroblasts ◽

Myosin I ◽

Section Electron

The isolated intestinal microvillus cytoskeleton (core) consists of four major proteins: actin, villin, fimbrin and brush border myosin-I. These proteins can assemble in vitro into structures resembling native microvillus cores. Of these components, villin and brush border myosin-I show tissue-specific expression, so they may be involved in the morphogenesis of intestinal microvilli. When introduced into cultured cells that normally lack the protein, villin induces a reorganization of the actin filaments to generate large surface microvilli. Here we examine the consequences of microinjecting brush border myosin-I either alone or together with villin into cultured fibroblasts. Injection of brush border myosin-I has no discernible effect on the overall morphology of the cells, but does become localized to either normal or villin-induced microvilli and other surface structures containing an actin cytoskeleton. Since some endogenous myosin-Is have been found associated with cytoplasmic vesicles, these results show that brush border myosin-I has a domain that specifically targets it to the plasma membrane in both intestinal and cultured cell systems. Ultrastructural examination of microvilli on control cultured cells revealed that they contain a far more highly ordered bundle of microfilaments than had been previously appreciated. The actin filaments in microvilli of villin-injected cells appeared to be more tightly cross-linked when examined by thin-section electron microscopy. In intestinal microvilli, the core bundle is separated from the plasma membrane by about 30 nm due to the presence of brush border myosin-I.(ABSTRACT TRUNCATED AT 250 WORDS)

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The iodide channel of the thyroid: a plasma membrane vesicle study

AJP Cell Physiology ◽

10.1152/ajpcell.1992.263.3.c590 ◽

1992 ◽

Vol 263 (3) ◽

pp. C590-C597 ◽

Cited By ~ 45

Author(s):

P. Golstein ◽

M. Abramow ◽

J. E. Dumont ◽

R. Beauwens

Keyword(s):

Plasma Membrane ◽

Chloride Transport ◽

Membrane Vesicle ◽

Membrane Vesicles ◽

Anion Channel ◽

Apical Plasma Membrane ◽

Plasma Membrane Vesicle ◽

Plasma Membrane Vesicles ◽

Bovine Thyroid ◽

Set Up

The uptake of radioactive iodide or chloride by plasma membrane vesicles of bovine thyroid was studied by a rapid filtration technique. A Na(+)-I- cotransport was demonstrated. When this Na(+)-I- cotransport is inactive (i.e., at 4 degrees C and in the absence of Na+), an uptake of iodide above chemical equilibrium could be induced, driven by the membrane potential. The latter was set up by allowing potassium to diffuse into the membrane vesicles in the presence of valinomycin and of an inward K+ gradient. This potential difference (positive inside) induced the uptake of iodide (or other anion present). The data support the existence of two anionic channels. The first one, observed at low near-physiological iodide concentration (micromolar range), which exhibits a high permeability and specificity for iodide (hence called the iodide channel), has a Km of 70 microM. The other one appears similar to the epithelial anion channel as described by Landry et al. (J. Gen. Physiol. 90: 779-798, 1987); it is still about fourfold more permeable to iodide than to chloride and presents a Km of 33 mM. Under physiological conditions the latter channel would mediate chloride transport, and the iodide channel, which is proposed to be restricted to the apical plasma membrane domain of the thyrocyte, transports iodide from the cytosol to the colloid space.

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