Early events elicited by Bombesin and structurally related peptides in quiescent Swiss 3T3 cells. I. Activation of protein kinase C and inhibition of epidermal growth factor binding

Journal Article · Tue Dec 31 23:00:00 EST 1985 · J. Cell Biol.; (United States)

DOI:https://doi.org/10.1083/jcb.102.6.2211· OSTI ID:5669743

Zachary, I; Sinnett-Smith, J W; Rozengurt, E

Addition of bombesin to quiescent cultures of Swiss 3T3 cells caused a rapid increase in the phosphorylation of an M/sub r/ 80,000 cellular protein (designated 80k). The effect was both concentration and time dependent. The 80k phosphoproteins generated in response to bombesin and to phorbol 12,13-dibutyrate were identical as judged by one- and two-dimensional PAGE and by peptide mapping after partial proteolysis with Staphylococcus aureus V8 protease. In addition, prolonged pretreatment of 3T3 cells with phorbol 12,13-dibutyrate, which leads to the disappearance of protein kinase C activity, blocked the ability of bombesin to stimulate 80k. Bombesin also caused a rapid (1 min) inhibition of /sup 125/I-labeled epidermal growth factor (/sup 125/I-EGF) binding to Swiss 3T3 cells. The inhibition was both concentration and temperature dependent and resulted from a marked decrease in the affinity of the EGF receptor for its ligand. These results strongly suggest that these responses are mediated by specific high-affinity receptors that recognize the peptides of the bombesin family in Swiss 3T3 cells. While an increase in cytosolic Ca/sup 2 +/ concentration does not mediate the bombesin inhibition of /sup 125/I-EGF binding, the activation of protein kinase C in intact Swiss 3T3 cells by peptides of the bombesin family may lead to rapid inhibition of the binding of /sup 125/I-EGF to its cellular receptor.

• Research Organization: Imperial Cancer Research Fund, London, England
• OSTI ID: 5669743
• Journal Information: J. Cell Biol.; (United States), Journal Name: J. Cell Biol.; (United States) Vol. 102; ISSN JCLBA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CELL CULTURES
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
GROWTH
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
MAMMALS
MICE
NUCLEI
ODD-EVEN NUCLEI
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
RADIOISOTOPES
REACTION KINETICS
RODENTS
TRACER TECHNIQUES
TRANSFERASES
VERTEBRATES