scholarly journals Association of the crosslinked IgE receptor with the membrane skeleton is independent of the known signaling mechanisms in rat basophilic leukemia cells.

1991 ◽  
Vol 2 (3) ◽  
pp. 181-191 ◽  
Author(s):  
J R Apgar

Crosslinking of the IgE receptor on the surface of rat basophilic leukemia (RBL) cells by multivalent antigen induces an association of these receptors with the detergent-insoluble membrane skeleton. Detergent insolubility of the receptor can also be induced on purified plasma membranes isolated from RBL cells by the use of either IgE oligomers or IgE monomers plus multivalent antigen. The critical event in initiating this interaction between the receptor and the membrane skeleton is cross-linking of the receptor. This association is rapid, and, when triggered by multivalent antigen, it is quickly reversed by the addition of excess monovalent antigen. The fact that this association occurs with the use of purified plasma membranes indicates that all of the components necessary for this interaction are present in the plasma membrane and that intracellular components are not required. Although crosslinking of the receptor activates phospholipase C and phospholipase A2 leading to the generation of several second messengers, none of these signaling mechanisms appears to be involved in IgE receptor interaction with the membrane skeleton. This interaction cannot be induced by phorbol 12-myristate 13-acetate (PMA), ionomycin, or a combination of these two reagents, although this will result in degranulation. Furthermore, receptor detergent insolubility is temperature independent when triggered by multivalent antigen, thus indicating that enzyme-catalyzed reactions are not important. This was verified by the fact that a variety of inhibitors that block phosphatidylinositol metabolism, arachidonic acid metabolism, Ca2+ influx, and protein kinase C (PKC) activation had no effect on antigen-induced association of the receptor with the membrane skeleton. These results indicate that the signaling mechanisms leading to the degranulation response are not involved in the association of the crosslinked receptor with the membrane skeleton.

1986 ◽  
Vol 17 (5-6) ◽  
pp. 418-426 ◽  
Author(s):  
G. Micklefield ◽  
W. König ◽  
Ph. Pfeiffer ◽  
A. Bohn

1997 ◽  
Vol 110 (6) ◽  
pp. 771-780 ◽  
Author(s):  
J.R. Apgar

Rat basophilic leukemia cells will adhere to and spread out on fibronectin coated surfaces in an integrin dependent manner. Adhesion and spreading on fibronectin leads to increased degranulation, inositol phosphate production, phospholipase D activation, and increased production of prostaglandin D2 and leukotriene C4 when the cells are activated through the high affinity IgE receptor. Rat basophilic leukemia cells will also adhere to surfaces coated with anti-rat class I antibodies, poly-L-lysine, and a lectin purified from Tetragonolobus purpureas. In all cases, antigen activated cells, which were adherent, displayed increased signaling, degranulation and eicosanoid production as compared to cells which were non-adherent. Cells which adhere to either anti-rat class I antibodies or poly-L-lysine also spread even though this is not mediated through integrins. In contrast, adhesion to the lectin from Tetragonolobus did not cause any appreciable spreading unless the cells were also triggered through the IgE receptor. Cells were also able to bind to fibronectin immobilized on polystyrene beads which mimics adhesion but does not allow spreading. However, these cells exhibited no increased signaling, degranulation, or eicosanoid production. Furthermore, rat basophilic leukemia cells can be modified by incubating them in the presence of biotinylated-phosphatidylserine which becomes incorporated into the membrane. These modified cells will adhere to streptavidin coated plates while unmodified cells will not. However, these modified cells do not spread, even after activation with antigen, and they show no increased degranulation or production of eicosanoids. These results indicate that adhesion itself is not sufficient for upregulation of the cells in response to antigen and that spreading of the cells may be the critical component.


Author(s):  
R.F. Stump ◽  
J.R. Pfeiffer ◽  
JC. Seagrave ◽  
D. Huskisson ◽  
J.M. Oliver

In RBL-2H3 rat basophilic leukemia cells, antigen binding to cell surface IgE-receptor complexes stimulates the release of inflammatory mediators and initiates a series of membrane and cytoskeletal events including a transformation of the cell surface from a microvillous to a lamellar topography. It is likely that dynamic properties of the IgE receptor contribute to the activation of these responses. Fewtrell and Metzger have established that limited crosslinking of IgE-receptor complexes is essential to trigger secretion. In addition, Baird and colleagues have reported that antigen binding causes a rapid immobilization of IgE-receptor complexes, and we have demonstrated an apparent increase with time in the affinity of IgE-receptor complexes for antigen.


1974 ◽  
Vol 249 (7) ◽  
pp. 2249-2257 ◽  
Author(s):  
C. Ronald Kahn ◽  
Pierre Freychet ◽  
Jesse Roth ◽  
David M. Neville

2019 ◽  
Vol 116 (31) ◽  
pp. 15686-15695 ◽  
Author(s):  
Damaris N. Lorenzo ◽  
Alexandra Badea ◽  
Ruobo Zhou ◽  
Peter J. Mohler ◽  
Xiaowei Zhuang ◽  
...  

βII-spectrin is the generally expressed member of the β-spectrin family of elongated polypeptides that form micrometer-scale networks associated with plasma membranes. We addressed in vivo functions of βII-spectrin in neurons by knockout of βII-spectrin in mouse neural progenitors. βII-spectrin deficiency caused severe defects in long-range axonal connectivity and axonal degeneration. βII-spectrin–null neurons exhibited reduced axon growth, loss of actin–spectrin-based periodic membrane skeleton, and impaired bidirectional axonal transport of synaptic cargo. We found that βII-spectrin associates with KIF3A, KIF5B, KIF1A, and dynactin, implicating spectrin in the coupling of motors and synaptic cargo. βII-spectrin required phosphoinositide lipid binding to promote axonal transport and restore axon growth. Knockout of ankyrin-B (AnkB), a βII-spectrin partner, primarily impaired retrograde organelle transport, while double knockout of βII-spectrin and AnkB nearly eliminated transport. Thus, βII-spectrin promotes both axon growth and axon stability through establishing the actin–spectrin-based membrane-associated periodic skeleton as well as enabling axonal transport of synaptic cargo.


2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Jie Zhou ◽  
Ying Jin ◽  
Ruijie Ma ◽  
Hongyun Song ◽  
Qin Chen ◽  
...  

Background. Both experimental and clinical studies have shown that electroacupuncture (EA) administration ameliorates chronic inflammatory pain (CIP). However, the multifaceted mechanism underlying the effects of EA on CIP is poorly understood. In this study, the mRNA transcriptome was used to study various therapeutic targets of EA. Methods. Using RNA-sequencing, protein-coding mRNA expression profiles of the L4-L5 dorsal root ganglion (DRG) were examined in the control (CN), complete Freund’s adjuvant- (CFA-) induced CIP, and EA-treated CIP groups. A series of bioinformatics analyses was performed; “EA-reversed upregulated genes with CIP” (up-DEGs) and “EA-reversed downregulated genes with CIP” (down-DEGs) were identified. Thereafter, based on up-DEGs and down-DEGs, biological functions and signaling pathways were enriched using gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses. Results. In total, 189 DEGs were identified, including 134 up- and 55 down-DEGs, which were enriched in arachidonic acid metabolism (rno00590), glutamatergic synapse (rno04724), serotonergic synapse (rno04726), FoxO signaling pathway (rno04068), insulin signaling pathway (rno04910), amyotrophic lateral sclerosis (rno05014), cholinergic synapse (rno04725), ECM-receptor interaction (rno04512), and choline metabolism in cancer (rno05231). Conclusion. We identified a few GOs, pathways, and genes that could play key roles in the amelioration of CIP by EA. Hence, this study may provide a theoretical basis for CIP amelioration by EA.


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