N-Acetylated α-linked acidic dipeptidase expressed in rat adipocytes is localized in the insulin-responsive glucose transporter (GLUT4) intracellular compartments and involved in the insulin-stimulated GLUT4 recruitment
| Autor: | Seung Yoon Park, Geum H Choi, Wan Lee, Byoung G Ha |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Glutamate Carboxypeptidase II
Male Dipeptidase Monosaccharide Transport Proteins Endosome medicine.medical_treatment Molecular Sequence Data Biophysics Muscle Proteins Biochemistry Exocytosis Rats Sprague-Dawley chemistry.chemical_compound Organophosphorus Compounds Adipocyte Adipocytes medicine Animals Insulin Amino Acid Sequence Enzyme Inhibitors Transport Vesicles Molecular Biology Regulation of gene expression Glucose Transporter Type 4 biology Peptide Fragments Recombinant Proteins Cell Compartmentation Rats Adipose Tissue chemistry Spectrometry Mass Matrix-Assisted Laser Desorption-Ionization biology.protein hormones hormone substitutes and hormone antagonists GLUT4 Intracellular Subcellular Fractions |
| Zdroj: | Archives of Biochemistry and Biophysics. 424:11-22 |
| ISSN: | 0003-9861 |
| DOI: | 10.1016/j.abb.2004.01.011 |
| Popis: | The GLUT4-containing vesicles purified from rat adipocyte contain many protein species of unknown identity, some of which are likely to play a critical role in the trafficking of GLUT4. Presently, we describe an 85-kDa protein in GLUT4-vesicles of rat adipocytes as a potential GLUT4 traffic regulatory protein. MALDI-TOF MS, RT-PCR, gene cloning, protein sequence analysis, and immunoreactivity assay have identified this protein as N-acetylated α-linked acidic dipeptidase (NAALADase) expressed in rat adipocytes. NAALADase in rat adipocytes was mostly membrane-associated and colocalized in discrete GLUT4-compartments with enrichment in putative GLUT4-sorting endosomes (G4GL). Total cell lysates of adipocytes exhibited NAALADase activity. Next, we treated rat adipocytes with 2-[phosphonomethy]pentanedionic acid (2-PMPA), a potent NAALADase inhibitor, and studied its effect on the distribution of GLUT4 and 3-O-methyl glucose (3OMG) flux. In 2-PMPA-treated adipocytes, there was a significant reduction (by 40%) in the insulin-stimulated GLUT4 translocation to the plasma membrane. The 3OMG flux in insulin-stimulated adipocytes was also delayed (51% of control) by 2-PMPA treatment, indicating that 2-PMPA impairs insulin-stimulated GLUT4 recruitment and the uptake of glucose. It is suggested that NAALADase may function as a regulator required for the insulin-stimulated GLUT4 vesicle movement and/or its exocytosis, thus may regulate insulin-induced GLUT4 recruitment in rat adipocytes. |
| Databáze: | OpenAIRE |
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