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Diacylglycerol treatment rapidly decreases the affinity of the epidermal growth factor receptors of Swiss 3T3 cells
Author(s) -
SinnettSmith James W.,
Rozengurt Enrique
Publication year - 1985
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041240114
Subject(s) - diacylglycerol kinase , protein kinase c , epidermal growth factor , receptor , phorbol , 3t3 cells , ligand (biochemistry) , protein kinase a , chemistry , biology , biochemistry , endocrinology , medicine , kinase , transfection , gene
The synthetic diacylglycerol 1‐oleoyl‐2‐acetyl glycerol (OAG) and phorbol esters activate protein kinase C in intact cells. We report here that OAG inhibits the binding of 125 I‐labelled epidermal growth factor ( 125 I‐EGF) to Swiss 3T3 cells. The inhibition was detected as early as 1 min after treatment at 37°C and persisted for at least 120 min. The effect of OAG was reversed upon removal of this diacylglycerol. Detailed Scatchard analysis of 125 I‐EGF binding to Swiss 3T3 cells at 4°C after a 1 h incubation with a saturating dose of OAG at 37°C, demonstrates that this OAG pretreatment does not change the apparent number of EGF receptors but causes a marked decrease in their apparent affinity for the ligand. Prolonged treatment (40 h) of the cells with phorbol dibutyrate (PBt 2 ) which causes a marked decrease in the number of phorbol ester binding sites and in the activity of protein kinase C, prevented the inhibition of 125 I‐EGF binding by both PBt 2 and OAG. The results support the possibility that protein kinase C plays a role in the transmodulation of the EGF receptor in intact cells.