Does the nuclear envelope contain two types of ligand‐gated Ca2+ release channels?

FEBS Letters

Rousseau, Eric¹  Proteau, Sonia¹  Guihard, Gilles¹ 

[1] Le Bilarium, Département de Physiologie et Biophysique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke QC J1H 5N4, Canada

关键词: Cell nucleus;    Nuclear Ca2+ channel;    Ca2+ signaling;    Inositol 1;    4;    5-trisphosphate;    Ryanodine;   

DOI  :  10.1016/S0014-5793(97)00949-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The nuclear envelope is composed of two membranes deliminating a perinuclear space which displays functional properties similar to those of a Ca²⁺-storing compartment. ATP-driven Ca²⁺ uptake and InsP₃-induced Ca²⁺ release processes have been described in isolated nuclei. Recently, it was reported that cADP-ribose and InsP₃ can trigger a nucleoplasmic Ca²⁺ increase. It was hypothesized that the inner nuclear membrane possesses Ca²⁺ channels that are regulated by ryanodine or InsP₃. Radio-ligand binding assays and Western blot experiments were performed in order to investigate their presence in sheep cardiac and rat liver nuclear envelopes. Ryanodine receptors (RyR) were not detected in liver nuclear envelopes by either binding assay or Western blot analysis. However, cardiac nuclear envelopes were found to retain a very low level of specific ryanodine binding, which was not detected on immuno-blots obtained with three types of isoform-specific RyR antibodies. In contrast, nuclear InsP₃-binding sites were consistently detected in both cardiac and liver nuclear envelopes. Altogether, these results provide evidence for the major contributor InsP₃-gated Ca²⁺ channels in control of Ca²⁺ release from the perinuclear space in liver and cardiac cells.

【 授权许可】

Unknown