Expression of polycystin-1 enhances endoplasmic reticulum calcium uptake and decreases capacitative calcium entry in ATP-stimulated MDCK cells

Abstract

Expression of polycystin-1 enhances endoplasmic reticulum calcium uptake and decreases capacitative calcium entry in ATP-stimulated MDCK cells.

The isolated polycystin-1 COOH-terminal can activate or block polycystin-1 signaling

“…As previously described [16], the decay phase of the ATP response was significantly accelerated by heterologously expressed pc-1 (progenitor pc-1 cell lines C8/68 and G7/36) relative to transfection control lines (progenitor control cell lines F6 and F8). Introduction of pkd193 into the progenitor control lines F6 and F8 resulted in a similar acceleration of decay of the ATP response.…”

“…The methods for detecting cytoplasmic and endoplasmic reticulum (ER) calcium responses to 10μM ATP and 10μM Inositol triphosphate (IP 3 ) using fura 2am and mag-fura 2am have been described previously [14,15]. In the latter, digitonin was used to allow release of cytoplasmic dye to reveal signal from residual dye in the ER lumen.…”

Human ADPKD primary cyst epithelial cells with a novel, single codon deletion in the PKD1 gene exhibit defective ciliary polycystin localization and loss of flow-induced Ca2+ signaling

“…The prolonged rate of Ca 2ϩ signal decay in PKD cyst cells treated with angiotensin II or vasopressin recalls that produced in ATP-stimulated M1 CCD cells by overexpression of a fusion protein containing the PC1 COOH-terminal cytoplasmic tail (69), attributed by those authors to prolongation of Ca 2ϩ entry. This prolonged rate of Ca 2ϩ signal decay may represent the converse of the accelerated Ca 2ϩ signal decay following ATP stimulation of MDCK cells overexpressing full-length PC1, attributed to enhanced ER Ca 2ϩ reuptake with inhibition of CCE (13). CCE inhibition by either overexpression or loss of PC1 function in PKD cyst cells parallels the ability of both underexpression and overexpression of PC1 to cause PKD in mice (60).…”

“…The flow response in all these cell types required both extracellular Ca 2ϩ and Ca 2ϩ -induced Ca 2ϩ release from internal stores. Although IP 3 -sensitive Ca 2ϩ stores were implicated in MDCK cells (13) and in the perfused rabbit CCD (22), ryanodine-sensitive stores seemed to predominate in the flow response in human NK cells and in mouse embryonic CCD cells. However, ryanodine receptor inhibitors can reduce IP 3 -mediated Ca 2ϩ signaling in colonic smooth muscle cells (27).…”

Polycystin-1 Interacts with Inositol 1,4,5-Trisphosphate Receptor to Modulate Intracellular Ca2+ Signaling with Implications for Polycystic Kidney Disease

“…We employed a fura-2 ratiometric Ca 2ϩ imaging assay to measure intracellular Ca 2ϩ release in polarized MDCK cells (MadinDarby canine kidney epithelial cells) that have stable expression of full-length PC1 (16,45). MDCK (MDCK zeo , F6) is known to form cysts when grown in a three-dimensional collagen gel and to have endogenous PC2.…”