Cell surface insertion of exogenous epidermal growth factor receptors into receptor- mutant cells: demonstration of insertion in the absence of added fusogenic agents.

Abstract

The [mouse] epidermal growth factor (EGF) receptor can be transferred in a biologically active orientation from donor hepatic membranes to recipient receptorless fibroblast cells. The recipient cells [mouse fibroblast 3T3 cell variant NR-6 cell] normally lack EGF receptors and are biologically unresponsive to EGF. The transfer of receptors from donor plasma membranes to recipient NR-6 surface membranes occurs in the absence of any added fusogenic agent. Studies on time and temperature dependence of this transfer indicate that it is due to preferential insertion of the EGF receptor over the other hepatic proteins. The inserted receptor is exceptionally stable to dissociation or damage, and this facilitated studies on its biological properties. The inserted receptor confers upon the hitherto unresponsive variant NR-6 cells a specific biological responsiveness to EGF as measured by EGF-induced stimulation of DNA replication and cell division. The existence of an affinity-mediated mechanism for the biologically active insertion of exogenous EGF receptors into receptorless variant cells is suggested. This insertion approach may be of use in the identification of receptor-associated membrane proteins that play a role in the transmission of EGF biological message.