Prion infection impairs lysosomal degradation capacity by interfering with rab7 membrane attachment in neuronal cells

Shim, Su Yeon; Karri, Srinivasarao; Law, Sampson; Schätzl, Hermann; Gilch, Sabine

doi:10.1038/srep21658

Cited by 35 publications

(38 citation statements)

References 63 publications

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“…5A). In contrast, while lysosome is also reported to regulate abnormal PrP clearance (38), lysosomal maturation, acidification, and overall degradation capacity are reportedly inhibited because of the inability of Rab7 to attach to vesicular membranes in prion-infected cells (39). Thus, we examined whether these impairments are reversed and whether lysosomal function is enhanced in melanin-treated ScN2a cells.…”

Section: Resultsmentioning

confidence: 94%

“…Membranebound Rab7 expression, lysosomal acidification, and lysosomal enzyme activity were all analyzed in cells as factors associated with lysosomal function. Because membrane-bound Rab7 expression is reportedly reduced in prion-infected cells, resulting in impaired lysosomal maturation and degradation capacity (39), membrane-bound Rab7 expression and total Rab7 expression were analyzed together by immunoblotting with anti-Rab7 antibody (Cell Signaling Technology, Danvers, MA). Crude membrane fractions were prepared for analyzing membrane-bound Rab7, as described previously (39), and cell lysate for analyzing total Rab7 was prepared with the lysis buffer.…”

Section: Methodsmentioning

confidence: 99%

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Melanin or a Melanin-Like Substance Interacts with the N-Terminal Portion of Prion Protein and Inhibits Abnormal Prion Protein Formation in Prion-Infected Cells

Hamanaka

Nishizawa

Sakasegawa

et al. 2017

J Virol

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Prion diseases are progressive fatal neurodegenerative illnesses caused by the accumulation of transmissible abnormal prion protein (PrP). To find treatments for prion diseases, we searched for substances from natural resources that inhibit abnormal PrP formation in prion-infected cells. We found that high-molecular-weight components from insect cuticle extracts reduced abnormal PrP levels. The chemical nature of these components was consistent with that of melanin. In fact, synthetic melanin produced from tyrosine or 3-hydroxy-l-tyrosine inhibited abnormal PrP formation. Melanin did not modify cellular or cell surface PrP levels, nor did it modify lipid raft or cellular cholesterol levels. Neither did it enhance autophagy or lysosomal function. Melanin was capable of interacting with PrP at two N-terminal domains. Specifically, it strongly interacted with the PrP region of amino acids 23 to 50 including a positively charged amino acid cluster and weakly interacted with the PrP octarepeat peptide region of residues 51 to 90. However, the and data were inconsistent with those of prion-infected cells. Abnormal PrP formation in protein misfolding cyclic amplification was not inhibited by melanin. Survival after prion infection was not significantly altered in albino mice or exogenously melanin-injected mice compared with that of control mice. These data suggest that melanin, a main determinant of skin color, is not likely to modify prion disease pathogenesis, even though racial differences in the incidence of human prion diseases have been reported. Thus, the findings identify an interaction between melanin and the N terminus of PrP, but the pathophysiological roles of the PrP-melanin interaction remain unclear. The N-terminal region of PrP is reportedly important for neuroprotection, neurotoxicity, and abnormal PrP formation, as this region is bound by many factors, such as metal ions, lipids, nucleic acids, antiprion compounds, and several proteins, including abnormal PrP in prion disease and the Aβ oligomer in Alzheimer's disease. In the present study, melanin, a main determinant of skin color, was newly found to interact with this N-terminal region and inhibits abnormal PrP formation in prion-infected cells. However, the data for prion infection in mice lacking melanin production suggest that melanin is not associated with the prion disease mechanism, although the incidence of prion disease is reportedly much higher in white people than in black people. Thus, the roles of the PrP-melanin interaction remain to be further elucidated, but melanin might be a useful competitive tool for evaluating the functions of other ligands at the N-terminal region.

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Section: Resultsmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Melanin or a Melanin-Like Substance Interacts with the N-Terminal Portion of Prion Protein and Inhibits Abnormal Prion Protein Formation in Prion-Infected Cells

Hamanaka

Nishizawa

Sakasegawa

et al. 2017

J Virol

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“…S1A) (11). The C179A mutant overwhelms the lysosomal capacity and eventually induces lysosomal dysfunction (18). This may Figure 5.…”

Section: Finally What Is the Importance Of Pmqc For Cells Or Organelmentioning

confidence: 99%

“…Otherwise, persistent RESET may be rather detrimental when the amount of its product overwhelms the capacity of the subsequent clearance pathway. Several studies demonstrating lysosomal dysfunction caused by prion infection support this hypothesis (18,19).…”

mentioning

confidence: 92%

Thiol‐disulfide status regulates quality control of prion protein at the plasma membrane

Lee

Shin

et al. 2019

FASEB j.

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Rapid endoplasmic reticulum (ER) stress‐induced export (RESET) is undoubtedly beneficial in that it eliminates misfolded prion protein (PrP) from a stressed ER. Considering that RESET induces rapid endocytosis of misfolded PrP for degradation, it is questionable whether RESET is beneficial when its product amount overwhelms the capacity of subsequent clearance pathways. We require a strategy to monitor the endocytic flux rate of misfolded PrPs. Here, we stabilized misfolded PrPs by inserting red fluorescent protein (RFP) and indirectly determined this rate by monitoring the lysosomal free RFP. We discovered a surveillance mechanism that limits endocytosis of misfolded PrPs through plasma membrane quality control (pmQC). pmQC was regulated by the thiol‐disulfide status of misfolded PrPs and consequently accumulates nonpathogenic PrP variants at the plasma membrane. This variant alleviated prion proteotoxicity induced by persistent RESET. Thus, PrP endocytosis is regulated by pmQC to ensure the safety of endolysosomal pathway from persistent internalization of misfolded PrP.—Lee, D., Lee, S., Shin, Y., Song, Y., Kang, S.‐W. Thiol‐disulfide status regulates quality control of prion protein at the plasma membrane. FASEB J. 33, 11567–11578 (2019). http://www.fasebj.org

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“…Together, these studies suggest that host cells upregulate lysosomal degradation as a response to prion infection. However, other studies have provided evidence suggesting that accumulation of prion aggregates inhibit lysosomal degradation by interfering with the ability of the cell to endocytose and degrade proteins 19 . Considering these opposing effects of prion infection on intracellular protein degradation, the net effect of PrP Sc accumulation on global protein turnover kinetics remains unclear.…”

Section: Introductionmentioning

confidence: 99%

Global analysis of protein degradation in prion infected cells

Hutti

Welle

Hryhorenko

et al. 2019

Preprint

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Prion diseases are rare neurological disorders caused by the misfolding of the cellular prion protein (PrP C ) into cytotoxic fibrils (PrP Sc ). Intracellular PrP Sc aggregates primarily accumulate within late endosomes and lysosomes, organelles that participate in the degradation and turnover of a large subset of the proteome. Thus, intracellular accumulation of PrP Sc aggregates have the potential to globally influence protein degradation kinetics within an infected cell. We analyzed the proteome-wide effect of prion infection on protein degradation rates in N2a neuroblastoma cells by dynamic stable isotopic labeling with amino acids in cell culture (dSILAC) and bottom-up proteomics. The analysis quantified the degradation rates of more than 4,700 proteins in prion-infected and uninfected cells. As expected, the degradation rate of the prion protein is significantly decreased upon aggregation in infected cells. In contrast, the degradation kinetics of the remainder of the N2a proteome generally increases upon prion infection. This effect occurs concurrently with increases in the cellular activities of autophagy and lysosomal hydrolases. The resulting enhancement in proteome flux may play a role in the survival of N2a cells upon prion infection.

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Prion infection impairs lysosomal degradation capacity by interfering with rab7 membrane attachment in neuronal cells

Cited by 35 publications

References 63 publications

Melanin or a Melanin-Like Substance Interacts with the N-Terminal Portion of Prion Protein and Inhibits Abnormal Prion Protein Formation in Prion-Infected Cells

Melanin or a Melanin-Like Substance Interacts with the N-Terminal Portion of Prion Protein and Inhibits Abnormal Prion Protein Formation in Prion-Infected Cells

Thiol‐disulfide status regulates quality control of prion protein at the plasma membrane

Global analysis of protein degradation in prion infected cells

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