Journalartikel

Jahr der Veröffentlichung: 2007

Seiten: 303-315

Zeitschrift: Cell Calcium

Bandnummer: 41

Heftnummer: 4

ISSN: 0143-4160

eISSN: 1532-1991

DOI Link: https://doi.org/10.1016/j.ceca.2006.07.009

Verlag: Elsevier

Abstract: 

The aim of the present study was the characterization of the subtypes of inositol 1,4,5-trisphosphate receptors (IP3R) in rat colonic epithelium. A monoclonal antibody against IP(3)R1 did not stain the colonic epithelial cells. In contrast, IP(3)R2 and IP(3)R3 were found within the epithelium; however, with a distinct intracellular localization and differences in their distribution along the crypt axis. IP(3)R2 immunoreactivity was found within the nuclei of the epithelial cells. The signal was distributed all over the nucleus and not restricted to the nuclear envelope as demonstrated by counterstaining with lamin B1 and electron microscopical examination after immunogold labelling. In contrast, an antibody against IP(3)R3 stained the epithelial cells mostly in their apical half in accordance with the typical localization Of IP3R in organelles such as the endoplasmic reticulum. In addition, there was a gradient from the surface region towards the crypt fundus, where the IP(3)R3 signal could not be detected.

Despite the strong IP(3)R3-gradient, in saponin-permeabilized colonic crypts exogenously administered IP3 or adenophostin A evoked a similar depletion of mag-fura-2-loaded intracellular Ca2+ stores in crypt and surface cells suggesting a contribution of the nuclear IP(3)R2 to the Ca2+ release. This conclusion was confirmed by experiments with isolated nuclei from colonic epithelium, at which IP3 was able to induce changes in the Ca2+ concentration, which were inhibited by 2-aminoethoxy-diphenylborate (2-APB), a blocker Of IP3 receptors. These results demonstrate that the colonic epithelial cells undergo changes in IP3R subtype expression during differentiation.

Harvard-Zitierstil: Siefjediers, A., Hardt, M., Prinz, G. and Diener, M. (2007) Characterization of inositol 1,4,5-trisphosphate (IP3) receptor subtypes at rat colonic epithelium, Cell Calcium, 41(4), pp. 303-315. https://doi.org/10.1016/j.ceca.2006.07.009

APA-Zitierstil: Siefjediers, A., Hardt, M., Prinz, G., & Diener, M. (2007). Characterization of inositol 1,4,5-trisphosphate (IP3) receptor subtypes at rat colonic epithelium. Cell Calcium. 41(4), 303-315. https://doi.org/10.1016/j.ceca.2006.07.009