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- Title
IP-induced cytosolic and nuclear Ca signals in HL-1 atrial myocytes: Possible role of IP receptor subtypes.
- Authors
Kim, Joon-Chul; Son, Min-Jeong; Subedi, Krishna; Kim, Do; Woo, Sun-Hee
- Abstract
HL-1 cells are the adult cardiac cell lines available that continuously divide while maintaining an atrial phenotype. Here we examined the expression and localization of inositol 1,4,5-trisphosphate receptor (IPR) subtypes, and investigated how pattern of IP-induced subcellular local Ca signaling is encoded by multiple IPR subtypes in HL-1 cells. The type 1 IPR (IPR1) was expressed in the perinucleus with a diffuse pattern and the type 2 IPR (IPR2) was expressed in the cytosol with a punctate distribution. Extracellular ATP (1 mM) elicited transient intracellular Ca releases accompanied by a Ca oscillation, which was eliminated by the blocker of IPRs, 2-APB, and attenuated by ryanodine. Direct introduction of IP into the permeabilized cells induced Ca transients with Ca oscillations at ⩾ 20 μM of IP, which was removed by the inhibition of IPRs using 2-APB and heparin. IP-induced local Ca transients contained two distinct time courses: a rapid oscillation and a monophasic Ca transient. The magnitude of Ca oscillation was significantly larger in the cytosol than in the nucleus, while the monophasic Ca transient was more pronounced in the nucleus. These results provide evidence for the molecular and functional expression of IPR1 and IPR2 in HL-1 cells, and suggest that such distinct local Ca signaling may be correlated with the punctate distribution of IPR2s in the cytosol and the diffuse localization of IPR1 in the peri-nucleus.
- Publication
Molecules & Cells (Springer Nature), 2010, Vol 29, Issue 4, p387
- ISSN
1016-8478
- Publication type
Article
- DOI
10.1007/s10059-010-0039-6