Susceptibility of myelin proteins to a neutral endoproteinase: The degradation of myelin basic protein (MBP) and P2 protein by purified bovine brain multicatalytic proteinase complex (MPC)

Lucas, J. Ramón De; Lobo, D.; Terry, Elaine; Hogan, Edward L.; Banik, Naren L.

doi:10.1007/bf00968410

Cited by 19 publications

(5 citation statements)

References 42 publications

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“…In this study, we have also found that inhibiting proteasomes resulted in a delay in the myelin sheath degradation. This may be caused by direct inhibition of myelin protein degradation by proteasome inhibitors because the protein components of the myelin sheath such as myelin basic protein and peripheral myelin protein 22 are known to be substrates for the UPS (Fortun et al,2005; Lucas et al,1992) or by secondary results of the inhibition of Schwann cell dedifferentiation.…”

Section: Discussionmentioning

confidence: 99%

Proteasome inhibition suppresses Schwann cell dedifferentiation in vitro and in vivo

Lee

Shin

Jung

et al. 2009

Glia

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The ubiquitin-proteasome system (UPS), lysosomes, and autophagy are essential protein degradation systems for the regulation of a variety of cellular physiological events including the cellular response to injury. It has recently been reported that the UPS and autophagy mediate the axonal degeneration caused by traumatic insults and the retrieval of nerve growth factors. In the peripheral nerves, axonal degeneration after injury is accompanied by myelin degradation, which is tightly related to the reactive changes of Schwann cells called dedifferentiation. In this study, we examined the role of the UPS, lysosomal proteases, and autophagy in the early phase of Wallerian degeneration of injured peripheral nerves. We found that nerve injury induced an increase in the ubiquitin conjugation and lysosomal-associated membrane protein-1 expression within 1 day without any biochemical evidence for autophagy activation. Using an ex vivo explant culture of the sciatic nerve, we observed that inhibiting proteasomes or lysosomal serine proteases prevented myelin degradation, whereas this was not observed when inhibiting autophagy. Interestingly, proteasome inhibition, but not leupeptin, prevented Schwann cells from inducing dedifferentiation markers such as p75 nerve growth factor receptor and glial fibrillary acidic protein in vitro and in vivo. In addition, proteasome inhibitors induced cell cycle arrest and cellular process formation in cultured Schwann cells. Taken together, these findings indicate that the UPS plays a role in the phenotype changes of Schwann cells in response to nerve injury.

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Section: Discussionmentioning

confidence: 99%

Proteasome inhibition suppresses Schwann cell dedifferentiation in vitro and in vivo

Lee

Shin

Jung

et al. 2009

Glia

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“…However, our data also suggest that both wt Cot and trunc-Cot are catabolized via the proteasome in an ubiquitylation-independent manner. In this context, it should be stressed that although the vast majority of proteins need to be polyubiquitylated prior to proteasome degradation, other proteins that do not need to be polyubiquitylated for proteasome degradation are starting to be identified (3,15,36,39,50,60,66). However, the possibility that an isopeptidase activity could hydrolyze the polyubiquitin chain cannot be excluded.…”

Section: Discussionmentioning

confidence: 99%

The COOH-Terminal Domain of Wild-Type Cot Regulates Its Stability and Kinase Specific Activity

Gándara

López

Hernando

et al. 2003

Molecular and Cellular Biology

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Cot, initially identified as an oncogene in a truncated form, is a mitogen-activated protein kinase kinase kinase implicated in cellular activation and proliferation. Here, we show that this truncation of Cot results in a 10-fold increase in its overall kinase activity through two different mechanisms. Truncated Cot protein exhibits a lower turnover rate (half-life, 95 min) than wild-type Cot (half-life, 35 min). The degradation of wild-type and truncated Cot can be specifically inhibited by proteasome inhibitors in situ. The 20S proteasome also degrades wild-type Cot more efficiently than the truncated protein. Furthermore, the amino acid 435 to 457 region within the wild-type Cot COOH-terminal domain confers instability when transferred to the yellow fluorescent protein and targets this fusion protein to degradation via the proteasome. On the other hand, the kinase specific activity of wild-type Cot is 3.8-fold lower than that of truncated Cot, and it appears that the last 43 amino acids of the wild-type Cot COOH-terminal domain are those responsible for this inhibition of kinase activity. In conclusion, these data demonstrate that the oncogenic activity of truncated Cot is the result of its prolonged half-life and its higher kinase specific activity with respect to wild-type Cot.The Cot/tpl-2 gene encodes a mitogen-activated protein (MAP) kinase kinase kinase that is potentially capable of switching on several MAP kinase cascades, namely those leading to the activation of the MAP kinases ERK1/ERK2, JNK, p38␥, and ERK5 (13,20,25,38,47,53). These signal transduction pathways link Cot activity with the up-regulation of several transcription factors, such as AP

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“…In experimental models, cell markers of oligodendrocytes such as CNPase (2′,3′-cyclic nucleotide-3′-phosphodiesterase), APC (Adenomatous Polyposis Coli), O4 or Olig family proteins are used in immunohistochemistry to evidence the cell-specific loss in demyelinating-prone areas [44,48,66]. In addition, staining (e.g., luxol fast blue, eriochrome R cyanin) and protein markers such as MBP, PLP, MOG, MAG are used to characterize the demyelinating nature of the lesions, keeping in mind that histological stains showed less specificity towards myelin subcomponents and that myelin proteins may be more or less susceptible to rapid degradation following myelin attack [67,68].…”

Section: From a Myelinating Oligodendrocyte Pathologymentioning

confidence: 99%

Osmotic Demyelination: From an Oligodendrocyte to an Astrocyte Perspective

Nicaise

Marneffe

Bouchat

et al. 2019

IJMS

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Osmotic demyelination syndrome (ODS) is a disorder of the central myelin that is often associated with a precipitous rise of serum sodium. Remarkably, while the myelin and oligodendrocytes of specific brain areas degenerate during the disease, neighboring neurons and axons appear unspoiled, and neuroinflammation appears only once demyelination is well established. In addition to blood‒brain barrier breakdown and microglia activation, astrocyte death is among one of the earliest events during ODS pathology. This review will focus on various aspects of biochemical, molecular and cellular aspects of oligodendrocyte and astrocyte changes in ODS-susceptible brain regions, with an emphasis on the crosstalk between those two glial cells. Emerging evidence pointing to the initiating role of astrocytes in region-specific degeneration are discussed.

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Susceptibility of myelin proteins to a neutral endoproteinase: The degradation of myelin basic protein (MBP) and P2 protein by purified bovine brain multicatalytic proteinase complex (MPC)

Cited by 19 publications

References 42 publications

Proteasome inhibition suppresses Schwann cell dedifferentiation in vitro and in vivo

Proteasome inhibition suppresses Schwann cell dedifferentiation in vitro and in vivo

The COOH-Terminal Domain of Wild-Type Cot Regulates Its Stability and Kinase Specific Activity

Osmotic Demyelination: From an Oligodendrocyte to an Astrocyte Perspective

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