ATP-dependent accumulation and inositol trisphosphate- or cyclic ADP-ribose-mediated release of Ca2+ from the nuclear envelope.
Uptake and release of Ca2+ from isolated liver nuclei were studied with fluorescent probes. We show with the help of digital imaging and confocal microscopy that the Ca(2+)-sensitive fluorescent probe Fura 2 is concentrated in or around the nuclear envelope and that the distribution of Fura 2 fluorescence is similar to that of an endoplasmic reticulum marker. The previously demonstrated ATP-dependent uptake of Ca2+ into isolated nuclei and release of the accumulated Ca2+ by inositol 1,4,5-trisphosphate (IP3) are therefore due to transport of Ca2+ into and out of the nuclear envelope and not the nucleoplasm. Dextrans labeled with fluorescent Ca2+ indicators (calcium-Green 1 and Fura 2) are distributed uniformly in the nucleoplasm and can be used to show that changes in the external Ca2+ concentration produce rapid changes in the nucleoplasmic Ca2+ concentration. Nevertheless, IP3 and cyclic ADP-ribose evoke transient intranuclear Ca2+ elevations. The release from the Ca2+ stores in or around the nuclear envelope appears to be directed into the nucleoplasm from where it can diffuse out through the permeable nuclear pore complexes.
Gerasimenko
O V
OV
Physiological Laboratory, University of Liverpool, England.
Gerasimenko
J V
JV
Tepikin
A V
AV
Petersen
O H
OH
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002232:Carbocyanines; D036563:Cyclic ADP-Ribose; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005456:Fluorescent Dyes; D016257:Fura-2; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D017136:Ion Transport / Q000187:drug effects; D008099:Liver / Q000166:cytology / Q000378:metabolism; D018613:Microscopy, Confocal; D008954:Models, Biological; D009685:Nuclear Envelope / Q000378:metabolism*; D012433:Ryanodine / Q000494:pharmacology
D002232:Carbocyanines; D005456:Fluorescent Dyes; D036563:Cyclic ADP-Ribose; D012433:Ryanodine; D000246:Adenosine Diphosphate Ribose; C007392:3,3'-dihexyl-2,2'-oxacarbocyanine; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D002118:Calcium; D016257:Fura-2