Send to

Choose Destination
J Biol Chem. 2004 Aug 20;279(34):35551-6. Epub 2004 Jun 11.

Functional coupling of chromogranin with the inositol 1,4,5-trisphosphate receptor shapes calcium signaling.

Author information

Department of Pharmacology and Cellular & Molecular Physiology, Yale University, New Haven, Connecticut 06520, USA.


Chromogranins A and B are high capacity, low affinity calcium (Ca(2+)) storage proteins that bind to the inositol 1,4,5-trisphosphate-gated receptor (InsP(3) R). Although most commonly associated with secretory granules of neuroendocrine cells, chromogranins have also been found in the lumen of the endoplasmic reticulum (ER) of many cell types. To investigate the functional consequences of the interaction between the InsP(3) R and the chromogranins, we disrupted the interaction between the two proteins by adding a chromogranin fragment, which competed with chromogranin for its binding site on the InsP(3)R. Responses were monitored at the single channel level and in intact cells. When using InsP(3) R type I incorporated into planar lipid bilayers and activated by cytoplasmic InsP(3) and luminal chromogranin, the addition of the fragment reversed the enhancing effect of chromogranin. Moreover, the expression of the fragment in the ER of neuronally differentiated PC12 cells attenuated agonist-induced intracellular Ca(2+) signaling. These results show that the InsP(3)R/chromogranin interaction amplifies Ca(2+) release from the ER and that chromogranin is an essential component of this intracellular channel complex.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center