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.

scholarly journals Capacitative Calcium Entry Deficits and Elevated Luminal Calcium Content in Mutant Presenilin-1 Knockin Mice

2000 ◽  
Vol 149 (4) ◽  
pp. 793-798 ◽  
Author(s):  
Malcolm A. Leissring ◽  
Yama Akbari ◽  
Christopher M. Fanger ◽  
Michael D. Cahalan ◽  
Mark P. Mattson ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Calcium Signaling ◽  
Intracellular Calcium ◽  
Brain Aging ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Capacitative Calcium Entry ◽  
Intracellular Calcium Stores ◽  
Agonist Stimulation

Dysregulation of calcium signaling has been causally implicated in brain aging and Alzheimer's disease. Mutations in the presenilin genes (PS1, PS2), the leading cause of autosomal dominant familial Alzheimer's disease (FAD), cause highly specific alterations in intracellular calcium signaling pathways that may contribute to the neurodegenerative and pathological lesions of the disease. To elucidate the cellular mechanisms underlying these disturbances, we studied calcium signaling in fibroblasts isolated from mutant PS1 knockin mice. Mutant PS1 knockin cells exhibited a marked potentiation in the amplitude of calcium transients evoked by agonist stimulation. These cells also showed significant impairments in capacitative calcium entry (CCE, also known as store-operated calcium entry), an important cellular signaling pathway wherein depletion of intracellular calcium stores triggers influx of extracellular calcium into the cytosol. Notably, deficits in CCE were evident after agonist stimulation, but not if intracellular calcium stores were completely depleted with thapsigargin. Treatment with ionomycin and thapsigargin revealed that calcium levels within the ER were significantly increased in mutant PS1 knockin cells. Collectively, our findings suggest that the overfilling of calcium stores represents the fundamental cellular defect underlying the alterations in calcium signaling conferred by presenilin mutations.

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 Junctate is a key element in calcium entry induced by activation of InsP3 receptors and/or calcium store depletion

2004 ◽  
Vol 166 (4) ◽  
pp. 537-548 ◽  
Author(s):  
Susan Treves ◽  
Clara Franzini-Armstrong ◽  
Luca Moccagatta ◽  
Christophe Arnoult ◽  
Cristiano Grasso ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Intracellular Calcium ◽  
Calcium Binding ◽  
Calcium Release ◽  
Transient Receptor Potential ◽  
Receptor Activation ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Store Depletion ◽  
Insp3 Receptors

In many cell types agonist-receptor activation leads to a rapid and transient release of Ca2+ from intracellular stores via activation of inositol 1,4,5 trisphosphate (InsP3) receptors (InsP3Rs). Stimulated cells activate store- or receptor-operated calcium channels localized in the plasma membrane, allowing entry of extracellular calcium into the cytoplasm, and thus replenishment of intracellular calcium stores. Calcium entry must be finely regulated in order to prevent an excessive intracellular calcium increase. Junctate, an integral calcium binding protein of endo(sarco)plasmic reticulum membrane, (a) induces and/or stabilizes peripheral couplings between the ER and the plasma membrane, and (b) forms a supramolecular complex with the InsP3R and the canonical transient receptor potential protein (TRPC) 3 calcium entry channel. The full-length protein modulates both agonist-induced and store depletion–induced calcium entry, whereas its NH2 terminus affects receptor-activated calcium entry. RNA interference to deplete cells of endogenous junctate, knocked down both agonist-activated calcium release from intracellular stores and calcium entry via TRPC3. These results demonstrate that junctate is a new protein involved in calcium homeostasis in eukaryotic cells.

Presenilin-1 and intracellular calcium stores regulate neuronal glutamate uptake

2004 ◽  
Vol 88 (6) ◽  
pp. 1361-1372 ◽  
Author(s):  
Yaxiong Yang ◽  
Gregory A. Kinney ◽  
William J. Spain ◽  
John C. S. Breitner ◽  
David G. Cook
Keyword(s):  
Intracellular Calcium ◽  
Glutamate Uptake ◽  
Presenilin 1 ◽  
Calcium Stores ◽  
Intracellular Calcium Stores
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