Association of phorbol ester-induced hyperphosphorylation and reversible regulation of transferrin membrane receptors in HL60 cells.

Abstract

Phorbol diesters are tumor-promoting agents that cause differentiation of HL60 human leukemic cells and concomitantly alter surface transferrin-receptor expression. Transferrin-receptor regulation is shown here to result from a rapid and reversible internalization process that is temporally associated with reversible increased phosphorylation (hyperphosphorylation) of the transferrin receptor. Such a reversible mechanism involving regulation of these surface proteins could result in the rapid generation of an early signal for HL60 cellular differentiation.