Abstract
In fat and muscle cells, the glucose transporter GLUT4 is sequestered in an intracellular compartment under basal conditions and redistributes markedly to the plasma membrane in response to insulin. Recently, we characterized a membrane aminopeptidase, designated IRAP (insulin-regulated aminopeptidase), that colocalizes with intracellular GLUT4 and similarly redistributes markedly to the plasma membrane in response to insulin in adipocytes. In contrast to GLUT4, IRAP is also expressed in 3T3-L1 fibroblasts, and this finding provided an opportunity to compare its subcellular distribution in fibroblasts and adipocytes. The relative amount of IRAP at the cell surface was measured by a cell surface biotinylation method. The portion of total IRAP at the cell surface in unstimulated adipocytes was 30% of that in unstimulated fibroblasts. Upon insulin treatment the portion of IRAP at the cell surface was the same in fibroblasts and adipocytes, and was increased 1.8-fold in fibroblasts and 8-fold in adipocytes. A similar analysis of the distribution of the transferrin receptor (TfR), the paradigm for recycling plasma membrane receptors, revealed that the portions of the TfR at the cell surface in both the basal and insulin-treated states were almost unchanged upon differentiation, and that insulin caused an increase of about 1. 6-fold in the amount of TfR at the cell surface. These results show that enhanced intracellular sequestration of IRAP occurs during adipogenesis, and that this effect underlies the larger insulin-elicited fold increase of IRAP at the cell surface in adipocytes.
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Selected References
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- Birnbaum M. J. The insulin-sensitive glucose transporter. Int Rev Cytol. 1992;137:239–297. [PubMed] [Google Scholar]
- Calderhead D. M., Kitagawa K., Tanner L. I., Holman G. D., Lienhard G. E. Insulin regulation of the two glucose transporters in 3T3-L1 adipocytes. J Biol Chem. 1990 Aug 15;265(23):13801–13808. [PubMed] [Google Scholar]
- Haney P. M., Slot J. W., Piper R. C., James D. E., Mueckler M. Intracellular targeting of the insulin-regulatable glucose transporter (GLUT4) is isoform specific and independent of cell type. J Cell Biol. 1991 Aug;114(4):689–699. doi: 10.1083/jcb.114.4.689. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Holman G. D., Lo Leggio L., Cushman S. W. Insulin-stimulated GLUT4 glucose transporter recycling. A problem in membrane protein subcellular trafficking through multiple pools. J Biol Chem. 1994 Jul 1;269(26):17516–17524. [PubMed] [Google Scholar]
- Hudson A. W., Ruiz M., Birnbaum M. J. Isoform-specific subcellular targeting of glucose transporters in mouse fibroblasts. J Cell Biol. 1992 Feb;116(3):785–797. doi: 10.1083/jcb.116.3.785. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ishii K., Hayashi H., Todaka M., Kamohara S., Kanai F., Jinnouchi H., Wang L., Ebina Y. Possible domains responsible for intracellular targeting and insulin-dependent translocation of glucose transporter type 4. Biochem J. 1995 Aug 1;309(Pt 3):813–823. doi: 10.1042/bj3090813. [DOI] [PMC free article] [PubMed] [Google Scholar]
- James D. E., Piper R. C., Slot J. W. Insulin stimulation of GLUT-4 translocation: a model for regulated recycling. Trends Cell Biol. 1994 Apr;4(4):120–126. doi: 10.1016/0962-8924(94)90066-3. [DOI] [PubMed] [Google Scholar]
- Kanai F., Nishioka Y., Hayashi H., Kamohara S., Todaka M., Ebina Y. Direct demonstration of insulin-induced GLUT4 translocation to the surface of intact cells by insertion of a c-myc epitope into an exofacial GLUT4 domain. J Biol Chem. 1993 Jul 5;268(19):14523–14526. [PubMed] [Google Scholar]
- Kandror K. V., Pilch P. F. gp160, a tissue-specific marker for insulin-activated glucose transport. Proc Natl Acad Sci U S A. 1994 Aug 16;91(17):8017–8021. doi: 10.1073/pnas.91.17.8017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kandror K. V., Yu L., Pilch P. F. The major protein of GLUT4-containing vesicles, gp160, has aminopeptidase activity. J Biol Chem. 1994 Dec 9;269(49):30777–30780. [PubMed] [Google Scholar]
- Keller S. R., Scott H. M., Mastick C. C., Aebersold R., Lienhard G. E. Cloning and characterization of a novel insulin-regulated membrane aminopeptidase from Glut4 vesicles. J Biol Chem. 1995 Oct 6;270(40):23612–23618. doi: 10.1074/jbc.270.40.23612. [DOI] [PubMed] [Google Scholar]
- Malide D., St-Denis J. F., Keller S. R., Cushman S. W. Vp165 and GLUT4 share similar vesicle pools along their trafficking pathways in rat adipose cells. FEBS Lett. 1997 Jun 16;409(3):461–468. doi: 10.1016/s0014-5793(97)00563-2. [DOI] [PubMed] [Google Scholar]
- Martin S., Rice J. E., Gould G. W., Keller S. R., Slot J. W., James D. E. The glucose transporter GLUT4 and the aminopeptidase vp165 colocalise in tubulo-vesicular elements in adipocytes and cardiomyocytes. J Cell Sci. 1997 Sep;110(Pt 18):2281–2291. doi: 10.1242/jcs.110.18.2281. [DOI] [PubMed] [Google Scholar]
- Martin S., Tellam J., Livingstone C., Slot J. W., Gould G. W., James D. E. The glucose transporter (GLUT-4) and vesicle-associated membrane protein-2 (VAMP-2) are segregated from recycling endosomes in insulin-sensitive cells. J Cell Biol. 1996 Aug;134(3):625–635. doi: 10.1083/jcb.134.3.625. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mastick C. C., Aebersold R., Lienhard G. E. Characterization of a major protein in GLUT4 vesicles. Concentration in the vesicles and insulin-stimulated translocation to the plasma membrane. J Biol Chem. 1994 Feb 25;269(8):6089–6092. [PubMed] [Google Scholar]
- Ross S. A., Scott H. M., Morris N. J., Leung W. Y., Mao F., Lienhard G. E., Keller S. R. Characterization of the insulin-regulated membrane aminopeptidase in 3T3-L1 adipocytes. J Biol Chem. 1996 Feb 9;271(6):3328–3332. doi: 10.1074/jbc.271.6.3328. [DOI] [PubMed] [Google Scholar]
- Shibasaki Y., Asano T., Lin J. L., Tsukuda K., Katagiri H., Ishihara H., Yazaki Y., Oka Y. Two glucose transporter isoforms are sorted differentially and are expressed in distinct cellular compartments. Biochem J. 1992 Feb 1;281(Pt 3):829–834. doi: 10.1042/bj2810829. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tanner L. I., Lienhard G. E. Insulin elicits a redistribution of transferrin receptors in 3T3-L1 adipocytes through an increase in the rate constant for receptor externalization. J Biol Chem. 1987 Jul 5;262(19):8975–8980. [PubMed] [Google Scholar]
- Verhey K. J., Yeh J. I., Birnbaum M. J. Distinct signals in the GLUT4 glucose transporter for internalization and for targeting to an insulin-responsive compartment. J Cell Biol. 1995 Sep;130(5):1071–1079. doi: 10.1083/jcb.130.5.1071. [DOI] [PMC free article] [PubMed] [Google Scholar]
- White S., Miller K., Hopkins C., Trowbridge I. S. Monoclonal antibodies against defined epitopes of the human transferrin receptor cytoplasmic tail. Biochim Biophys Acta. 1992 Jul 22;1136(1):28–34. doi: 10.1016/0167-4889(92)90081-l. [DOI] [PubMed] [Google Scholar]
- Yang J., Clark A. E., Kozka I. J., Cushman S. W., Holman G. D. Development of an intracellular pool of glucose transporters in 3T3-L1 cells. J Biol Chem. 1992 May 25;267(15):10393–10399. [PubMed] [Google Scholar]