scholarly journals Association of insulin-degrading enzyme with a 70 kDa cytosolic protein in hepatoma cells

1996 ◽  
Vol 319 (1) ◽  
pp. 149-158 ◽  
Author(s):  
François AUTHIER ◽  
Pamela H. CAMERON ◽  
Véronique TAUPIN
Keyword(s):  
Hepg2 Cells ◽  
Chinese Hamster Ovary Cells ◽  
Subcellular Location ◽  
Hepatoma Cells ◽  
Minor Amount ◽  
Type I ◽  
Insulin Degrading Enzyme ◽  
Western Blots ◽  
Degrading Enzyme ◽  
Cell Lysates

We have investigated the biosynthesis, subcellular location and expression of insulin-degrading enzyme (IDE), a type-I peroxisomal protease, in semi-permeabilized hepatoma cells using pulse-chase experiments, non-denaturing immunoprecipitation protocols and Northern-blot analyses. In HepG2 cell lysates prepared from cells radiolabelled with Tran[35S]-label, immunoprecipitated IDE was observed immediately after a 5 min pulse and subsequently declined during chase with t½ of approx. 33 h. In addition to the 110 kDa IDE protein, a protein of 70 kDa (p70) was identified in radiolabelled immunoprecipitates when using a monoclonal anti-IDE antibody 9B12 under non-denaturing conditions. This same antibody did not recognize p70 on Western blots of whole-cell lysates nor in sequential immunoprecipitates of immunocomplex-bead eluates from anti-IDE immunoprecipitations. Likewise, cross-linking studies performed on intact HepG2 and H35 hepatoma cells in vivo revealed the existence of a hetero-oligomeric complex of 180 kDa in which IDE and p70 were physically associated. Digitonin-permeabilization studies in normal and 35S-labelled HepG2 cells have defined a predominant association of IDE and its associated protein p70 with cytosol (supernatant); only a minor amount of the protein IDE was detected in peroxisomes (cellular pellet). Immunoprecipitation of IDE from 35S-labelled cell lysates of normal and stably transfected Chinese hamster ovary cells overexpressing IDE failed to detect p70. Treatment of HepG2 cells with clofibrate, a peroxisome proliferator, resulted in a dose-dependent increase of the two human IDE transcripts of 3.6 and 3.2 kb. This effect was not accompanied by a similar change at the protein level, nor by a change in the subcellular location of the proteins IDE and p70. Based on these findings we propose that in hepatoma cells: (1) IDE mainly exists in a stable cytoplasmic pool that is unchanged in cells undergoing peroxisomal proliferation; and (2) p70 binding to IDE may serve to maintain the dual cytosolic and peroxisomal pools of IDE in a stable equilibrium. Receieved 11 March 1996/30 May 1996; accepted 25 June 1996

IL-6 induced enhanced clearance of proANP and ANP by insulin-degrading enzyme in T1DM mouse

2021 ◽  
Author(s):  
Caiyun Li ◽  
Yao Wang ◽  
Guozhen Zhu ◽  
Yaxian Shang ◽  
Kang Jiefang ◽  
...  
Keyword(s):  
Type I Diabetes ◽  
Cardiovascular Complications ◽  
Mapk Signaling ◽  
Type I ◽  
Insulin Degrading Enzyme ◽  
Cvd Risk ◽  
Degrading Enzyme ◽  
The Relationship ◽  
Dose Dependent Increase

Cardiovascular disease (CVD) is the prevalent cause of morbidity and mortality in type I diabetes mellitus (T1DM) worldwide. However, the pathophysiological mechanisms underlying the relationship between CVD, CVD risk factors, and T1DM have not yet been sufficiently explored. Here we reported that insulin-degrading enzyme (IDE) effectively degrades the precursor of atrial natriuretic peptide (proANP) intracellular in HEK293T cells. Pro-inflammatory cytokine IL-6 elicited a significant dose-dependent increase in IDE protein expression. Inhibition of ERK/MAPK signaling pathway with selumetinib abolished IL-6-stimulated increase in IDE protein level and deceased in ANP secretion in H9C2 cells. Importantly, the T1DM mouse model displayed lower proANP in the heart and ANP in serum, due to increased IDE expression and activity. Our outcomes suggest a novel role of IL-6 on ANP metabolism via IDE and provide the possibilities for new potential therapeutic strategies for diabetes-related cardiovascular complications.

scholarly journals Ablation of amyloid precursor protein increases insulin-degrading enzyme levels and activity in brain and peripheral tissues

2019 ◽  
Vol 316 (1) ◽  
pp. E106-E120 ◽  
Author(s):  
Joshua A. Kulas ◽  
Whitney F. Franklin ◽  
Nicholas A. Smith ◽  
Gunjan D. Manocha ◽  
Kendra L. Puig ◽  
...  
Keyword(s):  
Amyloid Precursor Protein ◽  
Ex Vivo ◽  
Precursor Protein ◽  
Amyloid Peptide ◽  
Type I ◽  
Insulin Degrading Enzyme ◽  
Peripheral Tissues ◽  
Degrading Enzyme ◽  
Bodies Of Evidence

The amyloid precursor protein (APP) is a type I transmembrane glycoprotein widely studied for its role as the source of β-amyloid peptide, accumulation of which is causal in at least some cases of Alzheimer’s disease (AD). APP is expressed ubiquitously and is involved in diverse biological processes. Growing bodies of evidence indicate connections between AD and somatic metabolic disorders related to type 2 diabetes, and App−/− mice show alterations in glycemic regulation. We find that App−/− mice have higher levels of insulin-degrading enzyme (IDE) mRNA, protein, and activity compared with wild-type controls. This regulation of IDE by APP was widespread across numerous tissues, including liver, skeletal muscle, and brain as well as cell types within neural tissue, including neurons, astrocytes, and microglia. RNA interference-mediated knockdown of APP in the SIM-A9 microglia cell line elevated IDE levels. Fasting levels of blood insulin were lower in App−/− than App+/+ mice, but the former showed a larger increase in response to glucose. These low basal levels may enhance peripheral insulin sensitivity, as App−/− mice failed to develop impairment of glucose tolerance on a high-fat, high-sucrose (“Western”) diet. Insulin levels and insulin signaling were also lower in the App−/− brain; synaptosomes prepared from App−/− hippocampus showed diminished insulin receptor phosphorylation compared with App+/+ mice when stimulated ex vivo. These findings represent a new molecular link connecting APP to metabolic homeostasis and demonstrate a novel role for APP as an upstream regulator of IDE in vivo.

scholarly journals Glucose inhibits the insulin-induced activation of the insulin-degrading enzyme in HepG2 cells

Diabetologia ◽  
2009 ◽  
Vol 52 (8) ◽  
pp. 1656-1664 ◽  
Author(s):  
O. Pivovarova ◽  
Ö. Gögebakan ◽  
A. F. H. Pfeiffer ◽  
N. Rudovich
Keyword(s):  
Hepg2 Cells ◽  
Insulin Degrading Enzyme ◽  
Degrading Enzyme
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