Crosslinking of the receptors for immunoglobulin E depolarizes the plasma membrane of rat basophilic leukemia cells.
AUTOR(ES)
Kanner, B I
RESUMO
Aggregation of the receptor for IgE on mast cells, basophils, and a tumor analog, rat basophilic leukemia (RBL) cells, induces a calcium-dependent degranulation of the cells. We have measured the membrane potential (delta psi) of RBL cells during this reaction by using the tetraphenylphosphonium ion (Ph4P+) equilibration technique. We observed a 20-45% reduction in ionophore-sensitive Ph4P+ accumulation. The phenomenon persisted under conditions expected to collapse the mitochondrial membrane potential, consistent with the effect being due to a change in delta psi of the plasma membrane. We estimated that the change reflects a depolarization of 20 mV (from -90 to -70 mV, interior negative). Whereas degranulation fails to occur in the absence of external Ca2+, this was not true of the depolarization, indicating that the latter was not a consequence of secretion. When aggregation of the receptor is induced by reaction of the cell-bound IgE with a multivalent antigen, the secretory reaction can be halted by adding a univalent hapten. In this case, complete repolarization occurs. Equivalent depolarization was observed in the absence of Na+ but was diminished when both Ca2+ and Na+ were absent. Together, the data suggest that aggregation of the receptor opens ion channels and that the latter disappear promptly when the receptors are disaggregated. It is plausible that formation of these channels leads to the entry of Ca2+ and is an early and critical consequence of the aggregation of the receptors, thereby leading to degranulation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=384335Documentos Relacionados
- The receptor for immunoglobulin E on rat basophilic leukemia cells: effect of ligand binding on receptor expression.
- Resolution of cellular compartments involved in membrane potential changes accompanying IgE-mediated degranulation of rat basophilic leukemia cells.
- Leukotriene D: a slow reacting substance from rat basophilic leukemia cells.
- Association of the crosslinked IgE receptor with the membrane skeleton is independent of the known signaling mechanisms in rat basophilic leukemia cells.
- Isolation and characterization of leukotriene C4 synthetase of rat basophilic leukemia cells.