External ATP causes a passive permeability change in several transformed cells but not in untransformed mouse fibroblasts. In the present experiments, the ATP-specific permeability change was observed also in B16 melanoma and L929 cells. The sensitivity to external ATP of these cells increased further when the concentration of intracellular ATP was lowered by addition of a mitochondrial inhibitor. In contrast, mouse 3T3 cells transformed by murine sarcoma virus did not respond to external ATP even when the intracellular ATP was depleted. Such differences in the ATP-sensitivity were not ascribed to the different concentrations of intracellular ATP.

Adenosine Triphosphate↗

PubMedDate not supplied

Physicochemical properties of the mouse plasmacytoma cell membranes with modified phospholipids.

Earlier work from our laboratory has demonstrated that the modification of membrane phospholipid composition markedly retards secretion of immunoglobulin G1 by mouse plasmacytoma MOPC-31C cells. In the present study, we examined the physicochemical properties of lipid vesicles prepared from these cells with modified phospholipids by analyzing temperature dependence of 1H NMR signal line-widths of fatty-acyl chains. The results suggest that the export of IgG1 is affected by the local microenvironment of membranes rather than the bulk fluidity.

Animals↗