Nuclear Calcium: Transfer to and from the Cytosol

Abstract

Although the cell nucleus is known to control much of cell function, little is known as to the mediator of such function. Recent evidence has suggested that Ca²⁺ may be responsible for the regulation of many nuclear events. Early investigations have reported that the nucleus may be able to control its calcium function independently of the adjacent cytosol. IP₃ and IP₄ may act as regulators of nuclear Ca²⁺ independently or in parallel with the cytosol. This paper examines the current state of knowledge regarding nuclear calcium regulation. Additionally, a model for this regulation is proposed.

Microdomains bounded by endoplasmic reticulum segregate cell cycle calcium transients in syncytial Drosophila embryos

“…In this study, we demonstrate an additional, essential, and novel function—that of maintaining distinct calcium microdomains during cell division. Nuclear calcium has also been shown in some cell types to be regulated differentially to cytoplasmic calcium ( Badminton et al, 1998 ; MacDonald, 1998 ), but this is thought to be a result of the properties of the nuclear envelope rather than of an accumulation of ER around the nucleus. Although it was originally proposed that a nuclear envelope persisted throughout mitosis as a spindle envelope during syncytial nuclear divisions ( Harel et al, 1989 ), it is now clear that the nucleus becomes permeable to high molecular weight molecules early in prophase (that is, at the same time as in other cells) but that nuclear lamins persist until metaphase, disappearing before anaphase onset ( Paddy et al, 1996 ).…”

A novel gene expression pathway regulated by nuclear phosphoinositides

“…This interconversion of signaling molecules sets up an intriguing scenario, whereby, in the nucleus PI4,5P 2 generated by a PIP Kinase elicits a signal which can be turned off by a PLC isoform to rapidly generate IP3 and DAG. IP3 elicits calcium signaling which can affect a myriad of functions(Alonso et al, 2006; Bucki and Gorski, 2001; Choe and Ehrlich, 2006; Ehrlich et al, 1994; Irvine, 1982; MacDonald, 1998; Malviya and Klein, 2006; Miyazaki, 1993; Miyazaki, 1995). IP3 can be converted to higher order inositides IP4, IP5, IP6 , as well as PP-IP molecules, which could all carry out distinct nuclear processes(Macbeth et al, 2005; Seeds et al, 2007; York, 2006).…”