Abstract
The endocytosis of low density lipoprotein (LDL) and α2-macroglobulin (α2M) has been examined simultaneously in human skin fibroblasts. Incubation of cells at 4 °C with rhodamine-α2M and LDL plus [(dichlorotriazinyl)amino]fluorescein-anti-LDL gave a weak fluorescence for α2M and a brighter, clustered fluorescence for LDL. Following warming to 37 °C, LDL and α2M were observed to be coincident within endocytotic vesicles in the cell. By electron microscopy, LDL-ferritin and α2M-colloidal gold were present in the same coated pit at 4 °C. After 7 min at 37 °C, both ligands were observed in the same receptosome. Pretreatment of fibroblasts at 37 °C with 200-300 μM dansylcadaverine or 50 mM methylamine blocked clustering and internalization of both LDL and α2M. Bacitracin (5 mg ml-) blocked clustering and endocytosis of α2M, but not of LDL. These data indicate that both LDL and α2M are processed via the same endocytotic pathway in skin fibroblasts.
Original language | English (US) |
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Pages (from-to) | 15-22 |
Number of pages | 8 |
Journal | Experimental Cell Research |
Volume | 141 |
Issue number | 1 |
DOIs | |
State | Published - Sep 1982 |
ASJC Scopus subject areas
- Cell Biology