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Internalization of endothelial cell growth factor and its receptor by endothelial cells

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:6279023
The fate of /sup 125/I-labeled endothelial cell growth factor (/sup 125/I-ECGF) after binding to its cell surface receptor has been studied on murine lung capillary endothelial cells (LEII). Binding of /sup 125/I-ECGF to its receptor at 4/sup 0/C shows a sharp pH dependence with optimal binding at pH 7 and a marked decrease below pH 5.5. The majority of /sup 125/I-ECGF bound to cells at 4/sup 0/C can be removed by washing with low pH medium, but rapidly becomes acid-resistant upon shifting cells to 37/sup 0/C, with 50% of the /sup 125/I-ECGF becoming acid resistant after 20 min. Cell-bound /sup 125/I-ECGF is degraded slowly, with the appearance of trichloroacetic acid soluble degradation products in the medium after 8-12 hrs. Treatment of endothelial cells with the lysosomotropic amine chloroquine inhibits degradation and release of cell associated /sup 125/I-ECGF. SDS-PAGE analysis of internalized /sup 125/I-ECGF shows that it remains undergraded for up to 6 hrs after internalization. These data taken together indicate that after binding, /sup 125/I-ECGF is rapidly internalized and directed to the lysosomal cellular compartment where it is slowly degraded.
Research Organization:
Jerome H. Holland Lab., Rockville, MD
OSTI ID:
6279023
Report Number(s):
CONF-870644-
Conference Information:
Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
Country of Publication:
United States
Language:
English