Regulation of intracellular pH during the G1/S-phase transition of the neuroblastoma cell cycle.
Changes in active K+ and Na+ influx during the cell cycle of neuroblastoma (clone Neuro-2A) have suggested activation of an Na+, H+ exchange system during the G1/S-phase transition. Here we report that pHi, measured by the digitonin null-point method, is constant during G1-phase and the G1/S-phase transition and decreases in early S-phase. In addition pHi is shown to be most sensitive to the diuretic amiloride in the G1/S-phase transition, in agreement with the ion influx data. It is concluded from these data, that pHi is tightly regulated during the early cell cycle phases by the Na+, H+ exchange system, in particular during the G1/S-phase transition.
Boonstra
J
J
Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Utrecht.
Tertoolen
L G
LG
Mummery
C L
CL
de Laat
S W
SW
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007399:Interphase; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology*; D017923:Sodium-Hydrogen Exchangers; D014407:Tumor Cells, Cultured
D002352:Carrier Proteins; D017923:Sodium-Hydrogen Exchangers; D000584:Amiloride