Neuronal insulin receptors in Y79 retinoblastoma cells.
Immunoblot analysis of Y79 cell membrane proteins indicated that Y79 insulin receptors (InsRs) alpha subunits had a mass of 115 kDa. Biosynthetic studies revealed a typical transit time for InsR delivery to the Golgi (approximately 2h) and receptor processing. However, neither the proreceptor nor the mature receptor exhibited endoglycosidase H-resistance, consistent with a lack of N-linked glycan processing. Insulin stimulated a rapid and transient tyrosine phosphorylation of receptor beta subunits (95 kDa) and of IRS-1 in intact Y79 cells, whereas in vitro studies with enriched membrane glycoproteins resulted in the autophosphorylation of both InsR (95 kDa) and IGF-1-R (98k Da) beta subunits. These studies provide the first biochemical dissection of InsR structure and function in retinoblastoma cells.
Law
N M
NM
Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston 29425, USA.
Rosenzweig
S A
SA
D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D008970:Molecular Weight; D010766:Phosphorylation; D010920:Placenta / Q000378:metabolism; D011972:Receptor, Insulin / Q000737:chemistry / Q000378:metabolism*; D012160:Retina / Q000378:metabolism; D012175:Retinoblastoma / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D011972:Receptor, Insulin; D014357:Trypsin