Partial purification and characterization of insulin protease and its intracellular inhibitor from rat liver

McKenzie, Randolph A.; Burghen, George A.

doi:10.1016/0003-9861(84)90193-0

Cited by 18 publications

(8 citation statements)

References 13 publications

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“…The interaction with small, non-substrate proteins may also modulate IDE activity. A group of yet unidentified heatstable proteins of ~10-14 kDa has been shown to co-purify with IDE from liver and spleen homogenates and may behave in vitro as competitive inhibitors [35][36][37]. In one of these studies, ubiquitin was found to bind reversibly to IDE, displace insulin binding and inhibit its degradation [37].…”

Section: Regulation Of Ide Activitymentioning

confidence: 99%

Insulin-Degrading Enzyme: Structure-Function Relationship and its Possible Roles in Health and Disease

Fernandez-Gamba

Leal²,

Morelli³

et al. 2009

CPD

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Insulin-degrading enzyme (IDE) or insulysin is a highly conserved Zn(2+) -dependent endopeptidase with an "inverted" HxxEH motif. In vivo, IDE contributes to regulate the steady state levels of peripheral insulin and cerebral amyloid beta peptide (Abeta) of Alzheimer's disease. In vitro, substrates of IDE include a broad spectrum of peptides with relevant physiological functions such as atrial natriuretic factor, insulin-like growth factor-II, transforming growth factor-alpha, beta-endorphin, amylin or glucagon. The recently solved crystal structures of an inactive IDE mutant bound to four different substrates indicate, in accordance with previous compelling biochemical data, that peptide backbone conformation and size are major determinants of IDE recognition and substrate selectivity. IDE-N and IDE-C halves contribute to substrate binding and may rotate away from each other leading to open and closed conformers that permit or preclude the entry of substrates. Noteworthy, stabilization of substrate beta strands in their IDE-bound form may explain the preference of IDE for peptides with a high tendency to self-assembly as amyloid fibrils. These structural requirements may underlie the capability of some amyloid peptides of forming extremely stable complexes with IDE and raise the possibility of a dead-end chaperone-like function of IDE independent of catalysis. Furthermore, the recent recognition of IDE as a varicella zoster virus receptor and its putative involvement in muscle cell differentiation, steroid receptor signaling or proteasome modulation suggest that IDE is a multi-functional protein with broad and relevant roles in several basic cellular processes. Accordingly, IDE functions, regulation or trafficking may partake in the molecular pathogenesis of major human diseases and become potential targets for therapeutic intervention.

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Section: Regulation Of Ide Activitymentioning

confidence: 99%

Insulin-Degrading Enzyme: Structure-Function Relationship and its Possible Roles in Health and Disease

Fernandez-Gamba

Leal²,

Morelli³

et al. 2009

CPD

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“…Moreover, in APP transgenic mice, chronically elevated A␤ in the brain is associated with the up-regulation of plasminogen activator inhibitor-1 and inhibition of the tissue-type plasminogen activator-plasmin system (64). It has been shown that IDE activity in the liver may be regulated by heat-resistant, low molecular weight endogenous inhibitors, although their complete characterization has been elusive (36,65). In a recent report, one of such inhibitors has been proposed to be ubiquitin, which co-purified with IDE from mouse leukemic splenocytes and bound to it non-covalently in vitro (66).…”

Section: Fig 2 Sds-page and Western Blots Of Isolated Cerebral Cortmentioning

confidence: 99%

Insulin-degrading Enzyme in Brain Microvessels

Morelli

Llovera

Mathov

et al. 2004

Journal of Biological Chemistry

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The accumulation of amyloid ␤ (A␤) in the walls of small vessels in the cerebral cortex is associated with diseases characterized by dementia or stroke. These include Alzheimer's disease, Down syndrome, and sporadic and hereditary cerebral amyloid angiopathies (CAAs) related to mutations within the A␤ sequence. A higher tendency of A␤ to aggregate, a defective clearance to the systemic circulation, and insufficient proteolytic removal have been proposed as mechanisms that lead to A␤ accumulation in the brain. By using immunoprecipitation and mass spectrometry, we show that insulin-degrading enzyme (IDE) from isolated human brain microvessels was capable of degrading 125 I-insulin and cleaved A␤-(1-40) wild type and the genetic variants A␤ A21G (Flemish), A␤ E22Q (Dutch), and A␤ E22K (Italian) at the predicted sites. In microvessels from Alzheimer's disease cases with CAA, IDE protein levels showed a 44% increase as determined by sandwich enzymelinked immunosorbent assay and Western blot. However, the activity of IDE upon radiolabeled insulin was significantly reduced in CAA as compared with agematched controls. These results support the notion that a defect in A␤ proteolysis by IDE contributes to the accumulation of this peptide in the cortical microvasculature. Moreover they raise the possibility that IDE inhibition or inactivation is a pathogenic mechanism that may open novel strategies for the treatment of cerebrovascular A␤ amyloidoses.Amyloid ␤ (A␤) 1 peptide deposition in the walls of small arteries and less often in venules and capillaries of the cerebral cortex is a prominent feature of several neuropathological conditions characterized by dementia or stroke. These include Alzheimer's disease (AD), Down syndrome, and sporadic and autosomal dominant cerebral amyloid angiopathies (CAAs) (Ref. 1, and for a review, see Ref.2). In sporadic AD, a large proportion of the cases show A␤-(1-40) and A␤-(1-42/43) accumulation in the media and adventitia of brain vessels. Although the contribution of such deposits to the pathophysiology of dementia is not known, their extent and localization are strongly influenced by the apoE genotype (3-5). Sporadic CAA accounts for ϳ5% of strokes, and in this condition, A␤ wild type (wt) is the main component of amyloid deposits (Ref. 6, and for a review, see Ref. 7). The Flemish (A21G), Dutch (E22Q), and Italian (E22K) genetic variants of A␤ show a remarkable tendency to accumulate in the leptomeningeal and cortical vasculature leading to fatal hemorrhagic strokes around the 5th decade of life (8 -10). In addition, the Arctic (E22G) and Iowa (D23N) variants of A␤ present clinically with dementia, and yet at the pathological level they also show prominent vascular deposits (11,12). Interestingly the Dutch, Italian, and Iowa A␤ variants, when aggregated, are capable of inducing in vitro toxicity upon endothelial and smooth muscle cells, suggesting a pathogenic relationship between A␤ deposition, vascular pathology, and clinical manifestations (10,12,13). With regard to the underlyi...

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“…The protease is expressed in a variety of tissues including brain and has a conformational rather than a sequence specificity for its substrates (Shii et al, 1985;Akiyama et al, 1990;Kuo et al, 1994). In mammalian cells, IDE has been principally localized to the cytosol and peroxisomes (McKenzie and Burghen, 1984;Authier et al, 1995Authier et al, , 1996bChesneau et al, 1997), raising the question of how the enzyme could degrade A␤, because the peptide is not found in either of these locations. However, we have shown recently that intact IDE, like A␤, can be released into the extracellular fluid by healthy cultured microglial (BV-2) cells and is also present in normal CSF (Qiu et al, 1998).…”

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confidence: 99%

Neurons Regulate Extracellular Levels of Amyloid β-Protein via Proteolysis by Insulin-Degrading Enzyme

et al. 2000

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Progressive cerebral accumulation of amyloid beta-protein (Abeta) is an early and invariant feature of Alzheimer's disease. Little is known about how Abeta, after being secreted, is degraded and cleared from the extracellular space of the brain. Defective Abeta degradation could be a risk factor for the development of Alzheimer's disease in some subjects. We reported previously that microglial cells release substantial amounts of an Abeta-degrading protease that, after purification, is indistinguishable from insulin-degrading enzyme (IDE). Here we searched for and characterized a role for IDE in Abeta degradation by neurons, the principal cell type that produces Abeta. Whole cultures of differentiated pheochromocytoma (PC12) cells and primary rat cortical neurons actively degraded endogenously secreted Abeta via IDE. However, unlike that in microglia, IDE in differentiated neurons was not released but localized to the cell surface, as demonstrated by biotinylation. Undifferentiated PC12 cells released IDE into their medium, whereas after differentiation, IDE was cell associated but still degraded Abeta in the medium. Overexpression of IDE in mammalian cells markedly reduced the steady-state levels of extracellular Abeta(40) and Abeta(42), and the catalytic site mutation (E111Q) abolished this effect. We observed a novel membrane-associated form of IDE that is approximately 5 kDa larger than the known cytosolic form in a variety of cells, including differentiated PC12 cells. Our results support a principal role for membrane-associated and secreted IDE isoforms in the degradation and clearance of naturally secreted Abeta by neurons and microglia.

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Partial purification and characterization of insulin protease and its intracellular inhibitor from rat liver

Cited by 18 publications

References 13 publications

Insulin-Degrading Enzyme: Structure-Function Relationship and its Possible Roles in Health and Disease

Insulin-Degrading Enzyme: Structure-Function Relationship and its Possible Roles in Health and Disease

Insulin-degrading Enzyme in Brain Microvessels

Neurons Regulate Extracellular Levels of Amyloid β-Protein via Proteolysis by Insulin-Degrading Enzyme

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