The Insulin-like Growth Factor II/Mannose 6-Phosphate Receptor Utilizes the Same Membrane Compartments as GLUT4 for Insulin-dependent Trafficking to and from the Rat Adipocyte Cell Surface*
- ‡ To whom correspondence should be addressed: Dept. of Biochemistry, Boston University Medical School, 80 East Concord St., Boston, MA 02118. Tel.: 617-638-4044 or 617-638-4045; Fax: 617-638-5339.
Abstract
The insulin-like growth factor II (IGF-II)/mannose 6-phosphate (Man-6-P) receptor recycles in adipose cells between the cell surface and an intracellular storage pool, and the rate of this trafficking is markedly enhanced by insulin. We show here that the IGF-II/Man-6-P receptor is a constituent of the GLUT4-containing compartment (“GLUT4 vesicles”) where it represents gp230, a major recycling protein detected earlier by cell surface biotinylation (Kandror, K. V., and Pilch, P. F. (1994) J. Biol. Chem. 269, 138-142). The GLUT4 vesicles include 10-15% of the total and all of the acutely insulin-responsive recycling population of the IGF-II/Man-6-P receptor. The main part of the IGF-II/Man-6-P receptor population is excluded from the pathway of GLUT4 trafficking and either resides permanently in intracellular membranes or has a much slower rate of cycling to the cell surface. Thus, GLUT4 vesicles mediate the insulin-dependent delivery to the cell surface of the IGF-II/Man-6-P receptor as well as the other recyclable proteins with extracellular functional domains (GLUT4 and the aminopeptidase gp160).
Footnotes
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↵* This work was supported by Grant 195054 from the Juvenile Diabetes Foundation, Grant P30 DK46200 from NIDDK, National Institutes of Health, and Grant IN97-S from the American Cancer Society (to K. V. K.) and by Grants DK30425 and DK44269 from the National Institutes of Health (to P. F. P.). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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1 The abbreviations used are:
- gp
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glycoprotein
- IGF-II
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insulin-like growth factor II
- Man-6-P
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mannose 6-phosphate
- PBS
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phosphate-buffered saline
- LM
-
light microsome(s)
- PM
-
plasma membrane
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↵2K. V. Kandror and P. F. Pilch, unpublished observations.
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- Received April 26, 1996.
- Revision received June 10, 1996.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
