Endoplasmic reticulum generates calcium signalling microdomains around the nucleus and spindle in syncytial Drosophila embryos.
Cell cycle calcium signals are generated by inositol trisphosphate-mediated release of calcium from internal stores [Ciapa, Pesando, Wilding and Whitaker (1994) Nature (London) 368, 875-878; Groigno and Whitaker (1998) Cell 92, 193-204]. The major internal calcium store is the ER (endoplasmic reticulum): the spatial organization of the ER during mitosis is important in defining a microdomain around the nucleus and mitotic spindle in early Drosophila embryos [Parry, McDougall and Whitaker (2005) J. Cell Biol. 171, 47-59]. Nuclear divisions in syncytial Drosophila embryos are accompanied by both cortical and nuclear localized calcium transients. Mitosis is prevented by the InsP(3) antagonists Xestospongin C and heparin. Nuclear-localized transients and cortical transients rely on extraembryonic calcium, suggesting that ER calcium levels are maintained by calcium influx.
Parry
H
H
Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, UK.
McDougall
A
A
Whitaker
M
M
D000818:Animals; D020013:Calcium Signaling / Q000502:physiology*; D002467:Cell Nucleus / Q000737:chemistry / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000502:physiology*; D015726:Giant Cells / Q000737:chemistry / Q000502:physiology*; D021962:Membrane Microdomains / Q000737:chemistry / Q000502:physiology*; D008941:Spindle Apparatus / Q000737:chemistry / Q000502:physiology*