Calcium transport pathways in the nucleus.

Due to the availability of new biophysical and biochemical techniques, there has recently been considerable progress in our understanding of Ca2+ transport inside, as well as into and out of, the nucleus. A number of Ca2+ transport pathways have been localized specifically in the outer or inner nuclear membrane and the Ca2+ permeability through the nuclear pore complex has been assessed. The nuclear envelope has characteristics similar to those of a leaky epithelium. The leak is through the nuclear pore complex. The outer nuclear membrane contains the Ca2+ ATPase whereas the functionally important inositol trisphosphate (IP3)-activated Ca2+ release channels are specifically localized in the inner nuclear membrane.