Abstract:

We have studied the effects of brefeldin A (BFA) on the polarized delivery of the polymeric immunoglobulin receptor to the basolateral surface of MDCK cells. Unlike the delivery of several other basolateral membrane and secretory proteins, the delivery of the polymeric immunoglobulin receptor from the trans-Golgi network to the cell surface was inhibited by BFA. The effect of BFA treatment was apparent at 1.0 microgram/ml (36% inhibition), and maximal inhibition was observed at 10 micrograms/ml (70% inhibition). The delivery of the receptor from the endoplasmic reticulum to the basolateral surface was even more sensitive to the effect of BFA; delivery was inhibited 95% in cells treated with 1 micrograms/ml BFA. The selective action of BFA on the basolateral delivery of the polymeric immunoglobulin receptor suggests that there may be multiple pathways for delivery of proteins to the basolateral cell surface of MDCK cells.