Patchy accumulation of apical Na+ transporters allows cross talk between extracellular space and cell nucleus.
Intracellular Na+ activities and local current densities were measured in fused Madin-Darby canine kidney cells using Na+ and voltage-sensing microelectrodes. Na+ that enters the cell across the apical plasma membrane accumulates initially in the nucleoplasm, several seconds ahead of its appearance in the cell cytoplasm. The spatial distribution of Na+ currents, produced by a local superfusion of the cell surface, indicates a nonuniform, patchy accumulation of apical Na+ transporters in the vicinity of the nucleus. Such pathways for direct Na+ flux between extracellular space and cell nucleus could be potentially important for gene activation.
Oberleithner
H
H
Department of Physiology, University of Würzburg, Federal Republic of Germany.
Wünsch
S
S
Schneider
S
S
D000818:Animals; D001692:Biological Transport; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000378:metabolism*; D016764:Cell Polarity; D003593:Cytoplasm / Q000378:metabolism; D004285:Dogs; D004848:Epithelium / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism*; D066298:In Vitro Techniques; D007668:Kidney / Q000166:cytology; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000378:metabolism*
D015222:Sodium Channels; D012964:Sodium