Ultrastructural localization of concanavalin A receptors in the plasma membrane: association with underlying actin filaments

1988 ◽  
Vol 62 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Tetsuo KATSUMOTO ◽  
Takashi KURIMURA
Keyword(s):  
Plasma Membrane ◽  
Concanavalin A ◽  
Actin Filaments ◽  
Ultrastructural Localization ◽  
Membrane Association ◽  
Concanavalin A Receptors

scholarly journals Examining the Role of Actin-Plasma Membrane Association in Pseudomonas aeruginosa Infection and Type III Secretion Translocation in Migratory T24 Epithelial Cells

2012 ◽  
Vol 80 (9) ◽  
pp. 3049-3064 ◽  
Author(s):  
Dacie R. Bridge ◽  
Karen H. Martin ◽  
Elizabeth R. Moore ◽  
Wendy M. Lee ◽  
James A. Carroll ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Type Iii Secretion ◽  
Actin Filaments ◽  
Leading Edge ◽  
Membrane Association ◽  
Wild Type ◽  
Content Type ◽  
T24 Cells

ABSTRACTThe opportunistic pathogenPseudomonas aeruginosatargets wounded epithelial barriers, but the cellular alteration that increases susceptibility toP. aeruginosainfection remains unclear. This study examined how cell migration contributes to the establishment ofP. aeruginosainfections using (i) highly migratory T24 epithelial cells as a cell culture model, (ii) mutations in the type III secretion (T3S) effector ExoS to manipulateP. aeruginosainfection, and (iii) high-resolution immunofluorescent microscopy to monitor ExoS translocation. ExoS includes both GTPase-activating (GAP) and ADP-ribosyltransferase (ADPRT) activities, andP. aeruginosacells expressing wild-type ExoS preferentially bound to the leading edge of T24 cells, where ExoS altered leading-edge architecture and actin anchoring in conjunction with interrupting T3S translocation. Inactivation of ExoS GAP activity allowedP. aeruginosato be internalized and secrete ExoS within T24 cells, but as with wild-type ExoS, translocation was limited in association with disruption of actin anchoring. Inactivation of ExoS ADPRT activity resulted in significantly enhanced T3S translocation byP. aeruginosacells that remained extracellular and in conjunction with maintenance of actin-plasma membrane association. Infection withP. aeruginosaexpressing ExoS lacking both GAP and ADPRT activities resulted in the highest level of T3S translocation, and this occurred in conjunction with the entry and alignment ofP. aeruginosaand ExoS along actin filaments. Collectively, in using ExoS mutants to modulate and visualize T3S translocation, we were able to (i) confirm effector secretion by internalizedP. aeruginosa, (ii) differentiate the mechanisms underlying the effects of ExoS GAP and ADPRT activities onP. aeruginosainternalization and T3S translocation, (iii) confirm that ExoS ADPRT activity targeted a cellular substrate that interrupted T3S translocation, (iv) visualize the ability ofP. aeruginosaand ExoS to align with actin filaments, and (v) demonstrate an association between actin anchoring at the leading edge of T24 cells and the establishment ofP. aeruginosainfection. Our studies also highlight the contribution of ExoS to the opportunistic nature ofP. aeruginosainfection through its ability to exert cytotoxic effects that interrupt T3S translocation andP. aeruginosainternalization, which in turn limit theP. aeruginosainfectious process.

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

1984 ◽  
Vol 99 (1) ◽  
pp. 95s-103s ◽  
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.

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

1976 ◽  
Vol 69 (1) ◽  
pp. 51-72 ◽  
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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