Nuclear ion channels and regulation of the nuclear pore

Multiple K+, Cl-, and nonselective cationic nuclear channels have been identified in a variety of cell types from coconut endosperm to cardiac myocytes. To date, only one ligand-gated nuclear channel has been characterized-the InsP3R-but it is likely that others are also present. The InsP3R channel has been implicated in two important nuclear events: (1) nuclear vesicle fusion (Sullivan et al., 1993) and (2) regulation of molecular transport through the nuclear pore (Stehno-Bittel et al., 1993) and (2) 1995b). Regulation of passive diffusion across the nuclear envelope by the nuclear Ca2+ store may play an important role in nuclear events ranging from apoptosis to cell division.