Capacitative calcium entry is colocalised with calcium release in Xenopus oocytes: Evidence against a highly diffusible calcium influx factor

1996 ◽  
Vol 432 (2) ◽  
pp. 286-292 ◽  
Author(s):  
Carl C. H. Petersen ◽  
Michael J. Berridge
Keyword(s):  
Xenopus Oocytes ◽  
Calcium Release ◽  
Calcium Influx ◽  
Calcium Entry ◽  
Capacitative Calcium Entry

scholarly journals Molecular cloning and immunolocalization of a novel vertebrate trp homologue from Xenopus

1999 ◽  
Vol 340 (3) ◽  
pp. 593-599 ◽  
Author(s):  
Laura K. BOBANOVIĆ ◽  
Mika LAINE ◽  
Carl C. H. PETERSEN ◽  
Deborah L. BENNETT ◽  
Michael J. BERRIDGE ◽  
...  
Keyword(s):  
Antisense Oligonucleotides ◽  
Xenopus Oocytes ◽  
Transient Receptor Potential ◽  
Polyclonal Antibodies ◽  
Sequence Similarity ◽  
Receptor Potential ◽  
Calcium Entry ◽  
Capacitative Calcium Entry ◽  
Sequence Structure ◽  
Transient Receptor

We report the sequence, structure and distribution of a novel transient receptor potential (trp) homologue from Xenopus, Xtrp, determined by screening an oocyte cDNA library. On the basis of sequence similarity and predicted structure, Xtrp appears to be a homologue of mammalian trp1 proteins. Two polyclonal antibodies raised against distinct regions of the Xtrp sequence revealed Xtrp expression in various Xenopus tissues, and the localization of Xtrp at the plasma membrane of Xenopus oocytes and HeLa cells. Since capacitative calcium entry into Xenopus oocytes has been shown previously to be substantially inhibited by trp1 antisense oligonucleotides [Tomita, Kaneko, Funayama, Kondo, Satoh and Akaike (1998) Neurosci. Lett. 248, 195-198] we suggest that Xtrp may underlie capacitative calcium entry in Xenopus tissues.

scholarly journals Overexpression of inositol 1,4,5-trisphosphate 3-kinase in Xenopus oocytes inhibits agonist-evoked capacitative calcium entry

1994 ◽  
Vol 304 (3) ◽  
pp. 679-682 ◽  
Author(s):  
B Verjans ◽  
C C Petersen ◽  
M J Berridge
Keyword(s):  
Crucial Role ◽  
Xenopus Oocytes ◽  
Calcium Entry ◽  
Capacitative Calcium Entry ◽  
Inositol 1,4,5 Trisphosphate ◽  
Key Enzyme

Ins(1,4,5)P3 3-kinase is a key enzyme in the regulation of Ins(1,4,5)P3. Overexpression of Ins(1,4,5)P3 3-kinase inhibited agonist-evoked and Ins(1,3,4,5)P4-evoked Ca2+ entry in Xenopus oocytes, but did not inhibit Ca2+ entry evoked by thapsigargin or non-metabolizable Ins(1,4,5)P3 analogues. The data suggest that Ins(1,4,5)P3 alone plays the crucial role in the activation of capacitative Ca2+ entry by emptying intracellular stores.

Caffeine exerts a dual effect on capacitative calcium entry in Xenopus oocytes

2000 ◽  
Vol 12 (1) ◽  
pp. 31-35 ◽  
Author(s):  
Frédéric Hague ◽  
Fabrice Matifat ◽  
Gérard Brûlé ◽  
Thibault Collin
Keyword(s):  
Xenopus Oocytes ◽  
Calcium Entry ◽  
Capacitative Calcium Entry ◽  
Dual Effect

scholarly journals Putative capacitative calcium entry channels: expression of Drosophila trp and evidence for the existence of vertebrate homologues

1995 ◽  
Vol 311 (1) ◽  
pp. 41-44 ◽  
Author(s):  
C C Petersen ◽  
M J Berridge ◽  
M F Borgese ◽  
D L Bennett
Keyword(s):  
Intracellular Calcium ◽  
Xenopus Oocytes ◽  
Transient Receptor Potential ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Pcr Cloning ◽  
Capacitative Calcium Entry ◽  
Homologous Proteins ◽  
Major Pathway ◽  
Intracellular Calcium Stores

Capacitative calcium entry is a major pathway through which intracellular calcium stores are refilled after stimulation. It has been suggested that the protein encoded by the transient receptor potential (trp) gene expressed in Drosophila photoreceptors may be homologous with capacitative calcium entry channels. Expression of the trp gene product in Xenopus oocytes led to significant increases in calcium entry only when the intracellular calcium stores were depleted. Previous investigations have found trp to be uniquely expressed in Drosophila photoreceptors, but PCR cloning shows that homologous proteins exist in Calliphora, mouse brain and Xenopus oocytes. It is thus possible that capacitative calcium entry in Xenopus oocytes is mediated by a homologue of trp.

4-Aminopyridine activates calcium influx through modulation of the pore-forming purinergic receptor in human peripheral blood mononuclear cells

2004 ◽  
Vol 82 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Ingrid Lajdova ◽  
Dusan Chorvat, Jr. ◽  
Viera Spustova ◽  
Alzbeta Chorvatova
Keyword(s):  
Purinergic Receptors ◽  
Calcium Release ◽  
Mononuclear Cells ◽  
Calcium Influx ◽  
Purinergic Receptor ◽  
Human Peripheral Blood ◽  
Partial Agonist ◽  
Human Lymphocytes ◽  
Calcium Entry ◽  
Peripheral Blood Mononuclear

We investigated whether 4-aminopyridine (4AP), a drug recently linked to calcium influx and apoptosis, also affected purinergic receptor channels that are known to play an important role in the activation of T lymphocytes. The application of 4AP induced a rise in [Ca2+]i that was sensitive to nickel. This action was also observed in cells in which calcium reserves were emptied using thapsigargin (Tg). However, it was not present in the absence of extracellular Ca2+, despite full internal reserves. Adenosine trisphosphate (ATP), a partial agonist and a physiological activator of purinergic receptors, also stimulated Ca2+ entry independently of the calcium release from internal compartments. The effects of 4AP and ATP were not additive when studied on the same population of cells. KN-62 inhibited an increase in calcium entry induced by 4AP, while brilliant blue G (BBG) prevented it, supporting the hypothesis that purinergic P2X7 receptors are involved in this action. Furthermore, 4AP allowed entry of ethidium bromide (314 Da) but not propidium iodide (415 Da) into the cell, also corroborating the involvement of P2X7 pores. The presented results demonstrate, for the first time in human mononuclear cells isolated from healthy volunteers, that the P2X7 channel pore is involved in the action of 4AP and intervenes in the sustained calcium entry induced in response to 4AP.Key words: calcium, human lymphocytes, 4-aminopyridine, purinergic receptors.

scholarly journals Role of the Phospholipase C-Inositol 1,4,5-Trisphosphate Pathway in Calcium Release-activated Calcium Current and Capacitative Calcium Entry

2001 ◽  
Vol 276 (19) ◽  
pp. 15945-15952 ◽  
Author(s):  
Lisa M. Broad ◽  
Franz-Josef Braun ◽  
Jean-Philippe Lievremont ◽  
Gary St. J. Bird ◽  
Tomohiro Kurosaki ◽  
...  
Keyword(s):  
Phospholipase C ◽  
Calcium Current ◽  
Calcium Release ◽  
Calcium Entry ◽  
Capacitative Calcium Entry ◽  
Inositol 1,4,5 Trisphosphate
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