16-kilodalton heparin binding (fibroblast) growth factor type one appears in a stable 40-kilodalton complex after receptor-dependent internalization.
Incubation of 16-kDa 125I-labeled heparin binding (acidic fibroblast) growth factor type one (HBGF-1) with human hepatoma cells and normal rat hepatocytes resulted in the appearance of a stable 125I-labeled complex with an apparent molecular mass of 40 kDa. The complex could be isolated with specific antibodies against HBGF-1. In contrast to membrane receptor-bound 125I-HBGF-1, the complex was resistant to dissociation by detergents, acid, heat, and reducing or denaturing agents. Formation of a stable complex did not require treatment with cross-linking agents. Appearance of the 40-kDa complex was dependent on time, temperature, and enriched culture medium. Conditions that enhanced or reduced display of specific HBGF-1 membrane receptor sites enhanced or reduced the appearance of the 40-kDa complex. Dansylcadaverine, chloroquine, and staurosporine blocked the appearance of the 40-kDa complex concurrent with the blockage of internalization of the receptor-bound HBGF-1. Two-dimensional gel electrophoretic analysis, metabolic labeling with L-[35S]cysteine, and recovery of 16-kDa HBGF-1 from the 40-kDa complex after base treatment suggest involvement of a 24-kDa cellular protein in the complex formation. These results suggest a potentially novel receptor-dependent pathway for metabolism of HBGF-1.
Shi
E
E
W. Alton Jones Cell Science Center, Lake Placid, New York 12946.
Kan
M
M
Xu
J M
JM
McKeehan
W L
WL
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001710:Biotin / Q000737:chemistry; D002103:Cadaverine / Q000031:analogs & derivatives / Q000494:pharmacology; D002738:Chloroquine / Q000494:pharmacology; D003432:Cross-Linking Reagents; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism; D008970:Molecular Weight; D011233:Precipitin Tests; D051381:Rats; D019311:Staurosporine; D013696:Temperature; D014407:Tumor Cells, Cultured
D000470:Alkaloids; D003432:Cross-Linking Reagents; D005346:Fibroblast Growth Factors; D001710:Biotin; D002738:Chloroquine; D006493:Heparin; D019311:Staurosporine; C008542:monodansylcadaverine; D002103:Cadaverine