A ubiquitin ligase HRD1 promotes the degradation of Pael receptor, a substrate of Parkin

Endoplasmic reticulum-associated degradation (ERAD) is a constitutive process that identifies misfolded proteins in the ER and shuttles them to the cytosol, where they can be degraded by the proteasome. The accumulation of misfolded proteins can be catastrophic at both the cellular and organismal level. Although the players involved and mechanistic details of ERAD are being characterized, much remains to be learned. Because of the complexity of the pathway, experimental studies generally require labor-intensive biochemical techniques. Here, we report the development of a system to analyze ERAD based on mutants of split or intact Venus fluorescent protein for which fluorescence depends on enzymatic deglycosylation. We have generated variants that only become fluorescent when they are first glycosylated in the ER and subsequently deglycosylated after retrotranslocation into the cytosol. The E3 ubiquitin ligase HMG-coA reductase degradation 1 homolog (Hrd1) and, consistent with the demonstrated glycosylation/deglycosylation requirement, the cytosolic deglycosylating enzyme peptide:N′glycanase are both required for fluorescence. Furthermore, although these deglycosylation-dependent fluorescent proteins are themselves ERAD substrates, they can also be fused to additional ERAD substrates to interrogate substrate-specific pathways. To validate the system we performed a genomewide siRNA screen that successfully identified known ERAD factors such as Hrd1; homocysteine-inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1 (HERP); sel-1 suppressor of lin-12-like (SEL1L); and p97. These tools should greatly facilitate the identification of ERAD components and investigation of the mechanisms involved in this critical pathway.

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“…The E3 ubiquitin ligase Hrd1 is required for the ubiquitination and degradation of many ERAD substrates (8,(24)(25)(26)(27)(28)…”

Section: Resultsmentioning

confidence: 99%

Deglycosylation-dependent fluorescent proteins provide unique tools for the study of ER-associated degradation

Grotzke

Lu²,

Cresswell

2013

Proc. Natl. Acad. Sci. U.S.A.

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“…HRD1 promotes ubiquitination and degradation of Pael-R by recognizing its unfolded state. Suppression of HRD1 expression results in accumulation of unfolded Pael-R and ER stress-mediated apoptosis (38). These results suggest that functional loss of other E3s, including HRD1, is implicated in the dysfunctional Parkin-induced neurodegeneration in autosomal recessive juvenile parkinsonism.…”

Section: Hrd1 and Neurodegenerative Diseasementioning

confidence: 81%

Molecular Approaches to the Treatment, Prophylaxis, and Diagnosis of Alzheimer’s Disease: Possible Involvement of HRD1, a Novel Molecule Related to Endoplasmic Reticulum Stress, in Alzheimer’s Disease

2012

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Abstract. Endoplasmic reticulum (ER)-associated degradation (ERAD) is a protective mechanism against ER stress in which unfolded proteins accumulated in the ER are selectively transported to the cytosol for degradation by the ubiquitin-proteasome system. We cloned the novel ubiquitin ligase HRD1, which is involved in ERAD, and showed that HRD1 promoted amyloid precursor protein (APP) ubiquitination and degradation, resulting in decreased generation of amyloid β (Aβ). In addition, suppression of HRD1 expression caused APP accumulation and promoted Aβ generation associated with ER stress and apoptosis. Interestingly, HRD1 levels were significantly decreased in the cerebral cortex of patients with Alzheimer's disease (AD), and the brains of these patients experienced ER stress. Our recent study revealed that this decrease in HRD1 was due to its insolubilization; however, controversy persists about whether the decrease in HRD1 protein promotes Aβ generation or whether Aβ neurotoxicity causes the decrease in HRD1 protein levels. Here, we review current findings on the mechanism of HRD1 protein loss in the AD brain and the involvement of HRD1 in the pathogenesis of AD. Furthermore, we propose that HRD1 may be a target for novel AD therapeutics.

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“…We have shown that HRD1 is widely expressed in the substantia nigra and is partially coexistent with dopaminergic neurons (9). We have also shown that HRD1 is localized in the hippocampus, cerebral cortex, striatum, globus pallidus, and Purkinje cells of the cerebellar cortex (11).…”

mentioning

confidence: 82%

“…HRD1 is an E3 ubiquitin ligase localized in the ER and expressed during ER stress; it protects against ER stress-induced apoptosis (7,8). Furthermore, we have previously demonstrated that HRD1 promotes ubiquitination and degradation of Parkin-associated endothelin receptor-like receptor (Pael-R), a substrate for Parkin, and suppresses Pael-Rinduced ER stress and apoptosis (9). HRD1 is a central member of the ubiquitin ligase complexes that are responsible for the recognition and ubiquitination of misfolded proteins in the ER for subsequent degradation by proteasomes (10).…”

mentioning

confidence: 99%

Expression of the Ubiquitin Ligase HRD1 in Neural Stem/Progenitor Cells of the Adult Mouse Brain

et al. 2011

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Abstract. Neural stem/progenitor cells (NSCs) reside in the subventricular zone (SVZ) and subgranular zone of the hippocampal dentate gyrus in adult mammals. The ubiquitin ligase HRD1 is associated with degradation of amyloid precursor protein and believed to be specifically expressed in neurons and not in astrocytes. We investigated expression of HRD1 using immunohistochemistry and found colocalization of HRD1 with the NSC marker protein nestin and glial fibrillary acidic protein in the NSCs of the SVZ (the SVZ astrocytes) but not in the hippocampus. In the hippocampal dentate gyrus, HRD1 is localized in the nucleus of nestin-positive cells.

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A ubiquitin ligase HRD1 promotes the degradation of Pael receptor, a substrate of Parkin

Cited by 84 publications

References 45 publications

Deglycosylation-dependent fluorescent proteins provide unique tools for the study of ER-associated degradation

Deglycosylation-dependent fluorescent proteins provide unique tools for the study of ER-associated degradation

Molecular Approaches to the Treatment, Prophylaxis, and Diagnosis of Alzheimer’s Disease: Possible Involvement of HRD1, a Novel Molecule Related to Endoplasmic Reticulum Stress, in Alzheimer’s Disease

Expression of the Ubiquitin Ligase HRD1 in Neural Stem/Progenitor Cells of the Adult Mouse Brain

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