Perez-Montfort R, Fewtrell C, Metzger H
Biochemistry. 1983 Dec 6;22(25):5733-7. doi: 10.1021/bi00294a009.
Aggregation of the receptor for immunoglobulin E on mast cells and related tumor cells initiates exocytosis. We examined tumor cells that had incorporated [3H]leucine and 32P to see if stimulating them produced modifications in the receptors themselves. No changes were observed in the yield of receptors or in the relative proportion and the molecular weights of their alpha, beta, and gamma subunits. In addition, no new "receptor-associated" components were observed. However, after the cells were stimulated, the gamma chains of the receptors showed an average 35% decrease in their associated 32P. Changes in the beta subunits were more variable but on the average showed a similar-sized increase in 32P. Using a novel protocol that permitted examination of aggregated and unaggregated receptors from the same cell, we found that changes in the unaggregated receptors were quantitatively indistinguishable from those exhibited by the aggregated receptors. These findings raise the possibility that the changes are related to one of the inactivation reactions thought to accompany the activation sequence.
