Identification of the large-conductance background K+ channel in mouse B cells as TREK-2

2009 ◽  
Vol 297 (1) ◽  
pp. C188-C197 ◽  
Author(s):  
Haifeng Zheng ◽  
Joo Hyun Nam ◽  
Bo Pang ◽  
Dong Hoon Shin ◽  
Ji Seon Kim ◽  
...  
Keyword(s):  
B Cells ◽  
K Channel ◽  
Rt Pcr ◽  
Intact Cells ◽  
Membrane Stretch ◽  
Wehi 231 ◽  
Arachidonic Acids ◽  
Interfering Rna ◽  
Low Activity ◽  
Molecular Nature

Mouse B cells and their cell line (WEHI-231) express large-conductance background K+ channels (LKbg) that are activated by arachidonic acids, characteristics similar to TREK-2. However, there is no evidence to identify the molecular nature of LKbg; some properties of LKbg were partly different from the reported results of TREK type channels. In this study, we compared the properties of cloned TREK-2 and LKbg in terms of their sensitivities to ATP, phosphatidylinositol 4,5-bisphosphate (PIP2), intracellular pH (pHi), and membrane stretch. Similar to the previous findings of LKbg, TREK-2 showed spontaneous activation after membrane excision (i-o patch) and were inhibited by MgATP or by PIP2. The inhibition by MgATP was prevented by wortmannin, suggesting membrane-delimited regulation of TREKs by phosphoinositide (PI) kinase. The same was observed with the property of LKbg; the activation of TREK-2 by membrane stretch was suppressed by U73122 (PLC inhibitor). As with the known properties of TREK-2, LKbg were activated by acidic pHi and inhibited by PKC activator. Finally, we confirmed the expression of TREK-2 in WEHI-231 by using RT-PCR and immunoblot analyses. The amplitude of background K+ current and the TREK-2 expression in WEHI-231 were commonly decreased by genetic knockdown of TREK-2 using small interfering RNA. The downregulation of TREK-2 attenuated Ca2+-influx induced by arachidonic acid in WEHI-231. As a whole, these results strongly indicate that TREK-2 encodes LKbg in mouse B cells. We also newly suggest that the low activity of TREK-2 in intact cells is due to the inhibition by intrinsic PIP2.

Expression of TASK-2 and its upregulation by B cell receptor stimulation in WEHI-231 mouse immature B cells

2011 ◽  
Vol 300 (5) ◽  
pp. C1013-C1022 ◽  
Author(s):  
Joo Hyun Nam ◽  
Dong Hoon Shin ◽  
Haifeng Zheng ◽  
Dong-Sup Lee ◽  
Su Jung Park ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Single Channel ◽  
Calcineurin Inhibitors ◽  
Cell Receptor ◽  
Wehi 231 ◽  
Immature B Cells ◽  
Interfering Rna ◽  
First Time ◽  
Molecular Nature

Stimulation of B cell receptors (BCR ligation) induces apoptosis of immature B cells, which is critical to the elimination of self-reactive clones. In the mouse immature B cell line WEHI-231, the authors previously reported two types of background K+ channels with large (∼300 pS, LKbg) and medium (∼100 pS, MKbg) conductance in divalent cation-free conditions. While the authors have recently identified LKbg as TREK-2, the molecular nature of MKbg is unknown yet. In the present study, the authors found that BCR ligation markedly increased the background K+ conductance of WEHI-231. A single-channel study revealed that MKbg activity is increased by BCR ligation and that the biophysical properties (unitary conductance and pH sensitivity) of MKbg are consistent with those of TWIK-related acid-sensitive K+ channel 2 (TASK-2). The expression of TASK-2 and its upregulation by BCR ligation were confirmed by RT-PCR and immunoblot assays in WEHI-231. The BCR ligation-induced increase of K+ current was prevented by calcineurin inhibitors (cyclosporine A or FK506), and also by TASK-2-specific small interfering RNA (siRNA) transfection (si-TASK-2). Furthermore, si-TASK-2 attenuated the apoptosis of WEHI-231 caused by BCR ligation. TASK-2 activity and its mRNA were also confirmed in the primary splenic B cells of mouse. Summarizing, the authors report for the first time the expression of TASK-2 in B cells and surmise that the upregulation of TASK-2 by BCR ligation is associated with the apoptosis of immature B cells.

Activation by adrenaline of a low-conductance G protein-dependent K+ channel in mouse pancreatic B cells

Nature ◽  
1991 ◽  
Vol 349 (6304) ◽  
pp. 77-79 ◽  
Author(s):  
Patrik Rorsman ◽  
Krister Bokvist ◽  
Carina Ämmälä ◽  
Per Arkhammar ◽  
Per-Olof Berggren ◽  
...  
Keyword(s):  
B Cells ◽  
G Protein ◽  
K Channel ◽  
Pancreatic B Cells

LSP1 regulates anti-IgM induced apoptosis in WEHI-231 cells and normal immature B-cells

1999 ◽  
Vol 36 (6) ◽  
pp. 349-359 ◽  
Author(s):  
J Jongstra-Bilen ◽  
A Wielowieyski ◽  
V Misener ◽  
J Jongstra
Keyword(s):  
B Cells ◽  
Wehi 231 ◽  
Immature B Cells ◽  
Induced Apoptosis

Ultrastructure of the hepatopancreas of the Pacific white shrimp, Penaeus vannamei (Crustacea: Decapoda)

1988 ◽  
Vol 68 (2) ◽  
pp. 323-337 ◽  
Author(s):  
Thomas Caceci ◽  
Kay F. Neck ◽  
Donal D H. Lewis ◽  
Raymond F. Sis
Keyword(s):  
B Cells ◽  
Plasma Membranes ◽  
Ultrastructural Level ◽  
Pacific White Shrimp ◽  
White Shrimp ◽  
Penaeus Vannamei ◽  
Intact Cells ◽  
The Pacific ◽  
Total Complement ◽  
Electron Microscopes

Fourteen specimens of the hepatopancreas of the Pacific white shrimp, Penaeus vannamei, were prepared for examination with the transmission and scanning electron microscopes and with the light microscope. The histology and ultrastructure of this organ is similar to that seen in other Decapoda. At the ultrastructural level, it was observed that B-cells rupture at approximately the level of gap junctions located on the lateral plasma membranes of the cells, and discharge the contents of their large vacuoles into the intercellular space. This efflux of enzymatic material may be the mechanism by which cells are released from the wall of the tubule at the proximal end: the rupture and collapse of a B-cell may be analagous to the removal of the keystone which supports an arch. Deprived of support, and lacking structural adaptations for cohesion (there are no desmosomes or interdigitations in the epithelium) and with the intercellular material digested, the remaining intact cells collapse into the lumen of the tubule. The lysis of individual cells of all types - R-, F-, and B-cells - may contribute to the tubules’ total complement of digestive enzymes.

scholarly journals Apoptosis induced by the antigen receptor and Fas in a variant of the immature B cell line WEHI-231 and in splenic immature B cells

2001 ◽  
Vol 13 (4) ◽  
pp. 581-592 ◽  
Author(s):  
Maoxin Tim Tian ◽  
Chih-Hao Gilbert Chou ◽  
Anthony L. DeFranco
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Line ◽  
Antigen Receptor ◽  
Wehi 231 ◽  
Immature B Cells

scholarly journals Hypoxia increases KIAA1199/CEMIP expression and enhances cell migration in pancreatic cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takuya Oba ◽  
Norihiro Sato ◽  
Yasuhiro Adachi ◽  
Takao Amaike ◽  
Yuzan Kudo ◽  
...  
Keyword(s):  
Cell Migration ◽  
Protein Expression ◽  
Hypoxia Inducible Factor ◽  
Ductal Adenocarcinoma ◽  
Rt Pcr ◽  
Transwell Migration Assay ◽  
Migration Assay ◽  
Hypoxic Conditions ◽  
Mrna And Protein Expression ◽  
Interfering Rna

AbstractPancreatic ductal adenocarcinoma (PDAC) is characterised by dense desmoplasia and hypoxic microenvironment. Our previous reports demonstrated that hyaluronan (HA), especially low-molecular-weight HA, provides a favourable microenvironment for PDAC progression. However, the effect of hypoxia on HA metabolism remains unknown. Using quantitative real-time RT-PCR and western blot analysis, we analysed the changes in the expression of HA-synthesizing enzymes (HAS2 and HAS3) and HA-degrading enzymes (HYAL1, KIAA1199/CEMIP) in PDAC cell lines under hypoxic conditions. Hypoxia increased the mRNA and protein expression of KIAA1199, whereas it decreased HYAL1 expression. The expression of HAS3 was increased and HAS2 remained unchanged in response to hypoxia. The effect of KIAA1199 on hypoxia-induced cell migration was determined using a transwell migration assay and small-interfering RNA (siRNA). Hypoxia enhanced the migratory ability of PDAC cells, which was inhibited by KIAA1199 knockdown. We also used immunohistochemistry to analyse the protein expression of hypoxia inducible factor (HIF) 1α and KIAA1199 in PDAC tissues. There was a significant immunohistochemically positive correlation between KIAA1199 and HIF1α. These findings suggest that hypoxia-induced KIAA1199 expression may contribute to enhanced motility in PDAC.

Sequential induction of NF-kappa B/Rel family proteins during B-cell terminal differentiation

1994 ◽  
Vol 14 (8) ◽  
pp. 5349-5359
Author(s):  
H C Liou ◽  
W C Sha ◽  
M L Scott ◽  
D Baltimore
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Line ◽  
Cell Lineage ◽  
B Cell Differentiation ◽  
Nf Kappa B ◽  
Activator Proteins ◽  
I Kappa B Alpha ◽  
Wehi 231 ◽  
B Lineage

The NF-kappa B/Rel family of at least five transcription factor polypeptides is thought to function both as a developmental regulator in B cells and as a rapid response system in all cells. To examine this notion in more detail, we determined the protein contents of both the inducible and constitutive NF-kappa B/Rel activities in a pre-B-cell line, 70Z/3, and a mature B-cell line, WEHI 231. NF-kappa B p50/p65 is the major inducible nuclear complex after lipopolysaccharide or phorbol myristate acetate treatment of 70Z/3 cells. The constitutive and inducible complexes in WEHI 231 cells are mainly composed of p50 and Rel. The constitutive or induced activities are all sensitive to I kappa B-alpha, but this inhibitor is very short-lived in WEHI 231 cells, suggesting that the balance between synthesis and degradation of I kappa B-alpha determines whether a particular cell lineage has constitutive activity. A patterned expression of the NF-kappa B/Rel activator proteins emerges from an analysis of other B-lineage cell lines and splenic B cells: mainly p50 and p65 in pre-B (and non-B) cells, a predominance of Rel and p50 in mature B cells, and expression of p52 and RelB in plasmacytoma lines. This ordered pattern of regulators may reflect the requirement for expression of different genes during terminal B-cell differentiation because different combinations of NF-kappa B/Rel family members preferentially activate distinct kappa B sites in reporter constructs.

CD40 inhibits B cell apoptosis by upregulating bcl-xL expression and blocking oxidant accumulation

1997 ◽  
Vol 272 (3) ◽  
pp. C950-C956 ◽  
Author(s):  
W. Fang ◽  
K. A. Nath ◽  
M. F. Mackey ◽  
R. J. Noelle ◽  
D. L. Mueller ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cd40 Ligand ◽  
Antioxidant Response ◽  
Immunoglobulin M ◽  
Inhibitory Protein ◽  
Wehi 231 ◽  
Immature Mouse

Signaling through the CD40 receptor on human and murine B lymphocytes is necessary for germinal center formation and immunoglobulin class switching in vivo and rescues B cells from apoptosis triggered by cross-linking of surface immunoglobulin M in vitro. Ligation of CD40 on the immature mouse B cell line WEHI-231 with recombinant CD40 ligand (CD40L) was found to protect cells from apoptosis after gamma irradiation, as well as that following treatment with the sphingomyelin ceramide or compounds that deplete intracellular glutathione. CD40 signaling led to a rapid increase in the expression of the apoptosis inhibitory protein Bcl-xL. In addition, the apoptosis-induced accumulation of intracellular oxidants in WEHI-231 B cells was rapidly diminished by CD40 crosslinking. This antioxidant response was observed within 1 h and coincided with a preservation of intracellular thiols. These findings indicate that CD40 signaling induces a generalized cellular resistance to apoptosis characterized by an upregulation of Bcl-xL and changes in the intracellular redox potential.

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