TY - JOUR
T1 - Co-clustering and internalization of low-density lipoproteins and α2-macroglobulin in human skin fibroblasts
AU - Via, David P.
AU - Willingham, Mark C.
AU - Pastan, Ira
AU - Gotto, Antonio M.
AU - Smith, Louis C.
N1 - Funding Information:
Supportf or the researcha t Baylor College of Medicine was provided by the Robert A. Welch FoundationQ - 343, The National Heart and Blood Vessel Research and DemonstrationC enter, Baylor College of Medicine, a grant supportedr esearchp roject of the National Heart and Blood Institute HL-17269, USPHS HL-15648a, nd HL-07282.
PY - 1982/9
Y1 - 1982/9
N2 - 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.
AB - 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.
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U2 - 10.1016/0014-4827(82)90062-3
DO - 10.1016/0014-4827(82)90062-3
M3 - Article
C2 - 6180918
AN - SCOPUS:0020414511
SN - 0014-4827
VL - 141
SP - 15
EP - 22
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 1
ER -