Recombinant Mouse Derlin-3 (Derl3)

What is the molecular structure of Mouse Derlin-3 protein?

Mouse Derlin-3 is a multi-transmembrane protein that spans the endoplasmic reticulum (ER) membrane. It belongs to the Derlin family that shows homology to Der1p, a yeast transmembrane protein involved in ER-associated degradation (ERAD). The protein contains four transmembrane domains with both N-terminal and C-terminal regions oriented toward the cytosol. Experimental evidence indicates that Derlin-3 forms part of the retrotranslocation machinery in the ER membrane, though the precise structural arrangement requires further crystallographic analysis. Studies have shown that N-terminally tagged versions of Derlin-3 appear less stable than C-terminally tagged versions, suggesting potential conformational sensitivities that should be considered in experimental design .

How is Mouse Derlin-3 expression regulated at the tissue level?

Mouse Derlin-3 exhibits tissue-specific expression patterns distinct from other Derlin family members. While Derlin-1 is expressed ubiquitously across tissues, Derlin-3 expression is more restricted. Northern blot hybridization analyses demonstrate that Derlin-3 mRNA is particularly abundant in placenta, pancreas, spleen, and small intestine tissues. Interestingly, some cell types, including mouse embryonic fibroblasts (MEFs), show negligible expression of Derlin-3 mRNA under normal conditions. This tissue-specific expression pattern suggests specialized functions that may be context-dependent and requires consideration when selecting experimental models for Derlin-3 research .

What are the primary cellular functions of Mouse Derlin-3?

Mouse Derlin-3 functions as a critical component of the ER-associated degradation (ERAD) machinery, specifically targeting misfolded glycoproteins for degradation. Functional studies using overexpression and knockdown approaches have demonstrated that Derlin-3 facilitates the degradation of terminally misfolded ER proteins such as the null Hong Kong (NHK) mutant of α1-proteinase inhibitor. Derlin-3 participates in recognizing and extracting misfolded proteins from the ER for subsequent ubiquitination and proteasomal degradation in the cytosol. This function is essential for maintaining ER homeostasis, particularly under stress conditions that increase the burden of misfolded proteins in the ER .

What are the optimal conditions for expressing recombinant Mouse Derlin-3 in mammalian systems?

For optimal expression of recombinant Mouse Derlin-3 in mammalian systems, consider the following methodological approaches:

• Vector selection: Using mammalian expression vectors with strong promoters such as pIRES2-eGFP has shown success in multiple studies.

• Tag positioning: C-terminal tagging is preferable as N-terminal tags may destabilize the protein and affect its functionality. Pulse-chase analysis has demonstrated that N-terminally tagged proteins are significantly less stable than their C-terminally tagged counterparts .

• Cell line selection: HEK293 cells have demonstrated reliable expression of recombinant Derlin-3.

• Transfection methodology: Lipid-based transfection methods yield adequate transfection efficiency for most applications.

• Expression verification: Confirmation should be performed at both mRNA (Northern blot or qRT-PCR) and protein levels (Western blot), as mRNA expression doesn't always correlate with protein abundance.

When designing experiments, it's critical to include proper controls for transfection efficiency and to account for potential effects of overexpression on ER stress pathways that might confound experimental results.

How can researchers effectively measure Mouse Derlin-3 functional activity in cellular models?

Assessing Mouse Derlin-3 functional activity requires specialized approaches focusing on ERAD efficiency. Recommended methodological strategies include:

• ERAD substrate degradation assays: Use well-characterized ERAD substrates like the NHK mutant of α1-proteinase inhibitor. Pulse-chase experiments followed by immunoprecipitation with anti-α1-PI antibodies can quantitatively measure degradation rates. Functional Derlin-3 reduces the half-life of these model substrates .

• Dominant-negative approaches: Implement dominant-negative Derlin-3 constructs as experimental controls to verify specificity of observed effects. These constructs effectively decrease ERAD efficiency and serve as important negative controls .

• Cell viability under stress conditions: Measure cell survival under stress conditions like simulated ischemia, where functional Derlin-3 demonstrates protective effects. This approach is particularly relevant for cardiovascular research applications .

• Protein-protein interaction studies: Analyze Derlin-3 interactions with other ERAD components through co-immunoprecipitation or proximity labeling techniques to assess formation of functional degradation complexes.

These methods provide complementary data points for comprehensive evaluation of Derlin-3 functionality in experimental settings.

What are the validated methods for knockdown or knockout of Mouse Derlin-3 in research models?

For effective reduction of Mouse Derlin-3 expression in experimental models, the following validated approaches have been documented:

• RNA interference (RNAi): Short hairpin RNA (shRNA) expressed from vectors like pSUPER has demonstrated effective suppression of Derlin-3 expression. Target sequences should be carefully selected for specificity to avoid off-target effects on other Derlin family members. Northern blot hybridization can confirm knockdown efficiency and specificity .

• CRISPR-Cas9 genome editing: While not explicitly described in the provided literature, CRISPR-Cas9 approaches would enable complete knockout of Derlin-3.

• Dominant-negative constructs: Expression of functionally defective Derlin-3 variants can interfere with endogenous protein function, providing an alternative to direct knockdown approaches .

When implementing these approaches, researchers should verify knockdown at both mRNA and protein levels and assess potential compensatory changes in other Derlin family members (particularly Derlin-1 and Derlin-2), which may affect interpretation of experimental outcomes.

How does Mouse Derlin-3 respond to different types of cellular stress?

Mouse Derlin-3 exhibits distinct response patterns to various cellular stressors, particularly those affecting ER homeostasis:

• ER stress induction: Derlin-3 mRNA is significantly upregulated following treatment with ER stress inducers such as tunicamycin. The induction kinetics show a delayed response pattern compared to classical ER chaperones like BiP, suggesting regulation through specific UPR branches .

• Ischemic stress: Both simulated ischemia in cultured cardiomyocytes and actual myocardial infarction in vivo induce Derlin-3 expression. This upregulation represents a protective response aimed at enhancing ERAD capacity during ischemic challenge .

• Stress response regulation: Derlin-3 induction occurs primarily through the IRE1-XBP1 pathway of the unfolded protein response. Additionally, the ATF6 branch of the UPR plays a critical role in Derlin-3 upregulation in cardiac tissues .

The following table summarizes Derlin-3 responses to various stressors:

Understanding these stress-specific responses is crucial for appropriate experimental design when investigating Derlin-3 functions in pathophysiological contexts.

What role does Mouse Derlin-3 play in the unfolded protein response (UPR)?

Mouse Derlin-3 serves both as a target and effector of the unfolded protein response, particularly in the context of ER stress adaptation:

• UPR target gene: Derlin-3 is upregulated during ER stress primarily through the IRE1-XBP1 pathway, similar to EDEM (ER degradation enhancing α-mannosidase-like protein). In cardiac tissues, ATF6 activation also strongly induces Derlin-3 expression .

• UPR effector function: As a component of the ERAD machinery, Derlin-3 induction represents a critical adaptive mechanism that increases the cell's capacity to clear misfolded proteins from the ER, thus alleviating ER stress. This function positions Derlin-3 as part of the "quality control" arm of the UPR that complements the chaperone-mediated folding enhancement mechanisms .

• Temporal regulation: The induction time course of Derlin-3 follows a pattern similar to EDEM but distinctly slower than BiP induction, reflecting differences in transcription factor binding specificity and activation mechanisms between ATF6 and XBP1 .

• Tissue-specific UPR modulation: In cardiac tissue, Derlin-3 is a key mediator of ATF6-dependent protection against ischemic damage, highlighting tissue-specific roles in UPR-mediated cytoprotection .

This bidirectional relationship with the UPR positions Derlin-3 as an important factor in determining cell fate decisions during prolonged or severe ER stress.

How does Mouse Derlin-3 overexpression influence cellular responses to ischemic injury?

Overexpression of Mouse Derlin-3 confers significant cytoprotection against ischemic injury, particularly in cardiac contexts, through several mechanistic pathways:

• Enhanced ERAD capacity: Derlin-3 overexpression increases the efficiency of the ERAD pathway, accelerating the clearance of misfolded proteins that accumulate during ischemia. This prevents the toxic effects associated with protein aggregation and ER stress .

• Reduced ischemia-induced cell death: Experimental models demonstrate that cardiomyocytes overexpressing Derlin-3 exhibit markedly reduced cell death when subjected to simulated ischemia. This protective effect directly correlates with increased ERAD activity .

• Counteracted by dominant-negative inhibition: Expression of dominant-negative Derlin-3 variants not only negates this protection but actively increases cardiomyocyte vulnerability to ischemia-induced death, confirming the specificity of Derlin-3's protective function .

• Potential therapeutic implications: These findings suggest that strategies to enhance Derlin-3 expression or activity could represent a novel therapeutic approach for ischemic cardiac diseases, though translational challenges remain to be addressed .

These findings position Derlin-3 as a potential therapeutic target in ischemic heart disease and possibly other conditions characterized by proteotoxic stress.

What is the relationship between Mouse Derlin-3 and other Derlin family members in ERAD function?

The Derlin family exhibits complex functional relationships with both overlapping and distinct roles in ERAD pathways:

Understanding these relationships is essential for interpreting experimental data and designing targeted interventions that modulate specific ERAD pathways.

What are the experimental considerations when studying Mouse Derlin-3 in cancer models?

Investigating Mouse Derlin-3 in cancer models requires specific methodological approaches that address its unique properties and functions in tumorigenic contexts:

• Epigenetic regulation analysis: DERL3 promoter CpG island hypermethylation has been identified as a mechanism of gene inactivation in human tumors. When working with mouse cancer models, analysis of Derl3 promoter methylation status should be incorporated to parallel human pathobiology .

• Functional role assessment: As DERL3 shows tumor suppressor features, experiments should evaluate not only expression levels but functional consequences of Derl3 restoration in cancer cell lines. Both in vitro and in vivo approaches may be necessary to fully characterize tumor-suppressive effects .

• Downstream effector analysis: SLC2A1 (GLUT1) has been identified as a downstream target of DERL3-mediated degradation. Measurement of glucose uptake and glycolytic parameters is therefore essential when studying Derl3 functions in cancer contexts .

• Metabolic profiling: Given the connection to the Warburg effect, comprehensive metabolic profiling (including extracellular acidification rate and oxygen consumption measurements) should accompany Derl3 manipulation in cancer models .

• Therapeutic sensitivity testing: DERL3 status may influence sensitivity to glycolysis inhibitors. Drug response assays should be incorporated to evaluate potential therapeutic implications of Derl3 modulation .

These considerations ensure rigorous investigation of Derl3's role in cancer biology while addressing the specific molecular mechanisms that connect ERAD function to tumor metabolism.

How can proteomics approaches be optimized to identify Mouse Derlin-3 substrates and interacting partners?

Optimizing proteomics approaches for Mouse Derlin-3 substrate and interactome analysis requires specialized methodologies tailored to the challenges of studying ERAD components:

• SILAC for substrate identification: Stable isotopic labeling of amino acids in cell culture (SILAC) has been successfully employed to identify differential protein abundance between Derlin-3-expressing and control cells. This approach revealed SLC2A1 as a Derlin-3 substrate. Implementation requires:

  • Complete isotopic incorporation (typically >95%)

  • Paired comparison between Derlin-3-expressing and control cells

  • Validation of identified substrates through complementary approaches

• Temporal dynamics analysis: Pulse-chase experiments combined with immunoprecipitation enable assessment of degradation kinetics for candidate substrates. This approach is essential for distinguishing direct ERAD substrates from secondary effects of Derlin-3 expression .

• Membrane protein-specific techniques: Given Derlin-3's transmembrane nature, specialized approaches for membrane protein complexes are required, including:

  • Crosslinking strategies

  • Detergent optimization for complex preservation

  • Blue native PAGE for maintaining native interactions

• Validation strategies: Potential interactors or substrates identified through proteomics should be validated through:

  • Co-immunoprecipitation experiments

  • Dominant-negative competition assays

  • Directed degradation assays for putative substrates

These methodological considerations address the specific challenges associated with studying the dynamic protein-protein interactions within the ERAD machinery and enable more reliable identification of physiological Derlin-3 substrates.

How might Mouse Derlin-3 research translate to therapeutic applications in cardiac disease?

Mouse Derlin-3 research presents several promising translational pathways for therapeutic development in cardiac disease:

The strong experimental evidence for Derlin-3's protective role in cardiac contexts positions it as a promising target for therapeutic development, though significant translational challenges remain to be addressed.

What are the methodological approaches for studying Mouse Derlin-3 in models of neurodegeneration?

While the provided search results don't directly address Derlin-3 in neurodegeneration, existing knowledge about ERAD in protein aggregation diseases suggests several methodological approaches:

• Applicable model systems:

  • Transgenic mouse models expressing aggregate-prone proteins (e.g., mutant SOD1, tau, or α-synuclein)

  • Primary neuronal cultures subjected to proteotoxic stress

  • iPSC-derived neurons from patients with neurodegenerative diseases

• Experimental assessment approaches:

  • Quantitative analysis of Derlin-3 expression in affected brain regions

  • Correlation between Derlin-3 levels and disease progression markers

  • Manipulation of Derlin-3 expression through viral vectors in specific brain regions

  • Assessment of aggregate clearance efficiency with modified Derlin-3 levels

• Technical considerations:

  • Regional specificity is critical given the selective vulnerability in neurodegenerative diseases

  • Age-dependent effects must be considered in experimental design

  • Cell-type specific analyses are essential due to differential vulnerability

• Potential hypotheses to test:

  • Derlin-3 upregulation as a compensatory mechanism in early disease stages

  • Progressive failure of Derlin-3-mediated ERAD as a contributor to disease progression

  • Differential effects of Derlin-3 modulation on different aggregate-prone proteins

These approaches would extend the demonstrated protective role of Derlin-3 in cardiac contexts to neurodegenerative disease models, where protein aggregation and ER stress are well-established pathological mechanisms.

How can researchers address translational challenges when moving from Mouse Derlin-3 studies to human applications?

Transitioning research findings from mouse Derlin-3 studies to human applications presents several translational challenges that require systematic methodological approaches:

• Species conservation analysis: Although Derlin-3 function is likely conserved, comprehensive comparison of mouse and human Derlin-3 should address:

  • Sequence homology and structural similarities

  • Expression patterns across corresponding tissues

  • Regulatory mechanisms and stress responsiveness

  • Substrate specificity and ERAD pathway integration

• Human tissue validation: Findings from mouse models should be validated in:

  • Human tissue samples from relevant pathologies (e.g., ischemic heart tissue)

  • Human cell lines and primary cell cultures

  • iPSC-derived specialized cell types for disease modeling

• Therapeutic development considerations:

  • Target assessment: Determine if direct Derlin-3 targeting or upstream modulation (e.g., ATF6 activation) is more feasible

  • Delivery challenges: Develop strategies for tissue-specific enhancement of Derlin-3 activity

  • Safety evaluation: Assess potential consequences of ERAD enhancement on normal protein turnover

• Clinical correlation studies:

  • Analysis of DERL3 expression, regulation, or polymorphisms in patient cohorts

  • Assessment of DERL3 status as a potential biomarker for disease progression or therapeutic response

  • Retrospective analysis of existing patient data for correlations between DERL3 status and disease outcomes

• Ethical and regulatory considerations:

  • Development of appropriate safety biomarkers for first-in-human studies

  • Design of clinically relevant endpoints that reflect the mechanistic role of Derlin-3

Addressing these translational challenges systematically will facilitate the development of Derlin-3-based therapeutic strategies with the greatest potential for clinical impact.

What are common technical issues when working with recombinant Mouse Derlin-3 expression systems?

Researchers working with recombinant Mouse Derlin-3 frequently encounter several technical challenges that require specific troubleshooting strategies:

• Protein stability issues: N-terminally tagged Derlin-3 constructs demonstrate significantly reduced stability compared to C-terminally tagged versions, as evidenced by pulse-chase analysis. This instability may reflect improper membrane insertion or protein folding .

  • Solution: Prioritize C-terminal tagging strategies for recombinant expression studies.

• Membrane insertion heterogeneity: Experimental evidence suggests that overexpressed Derlin-3 may not insert uniformly into ER membranes, potentially affecting functional studies .

  • Solution: Employ careful subcellular fractionation and topology analysis to verify proper membrane insertion.

• UPR activation by overexpression: As an ER transmembrane protein, overexpression of Derlin-3 may itself trigger ER stress responses, confounding experimental interpretation.

  • Solution: Include appropriate controls to distinguish direct Derlin-3 effects from secondary stress responses.

• Tissue-specific expression challenges: The restricted expression pattern of endogenous Derlin-3 suggests potential tissue-specific cofactors that may be required for optimal function .

  • Solution: Consider cell type selection carefully when designing overexpression studies.

• Functional redundancy with other Derlins: Partial functional overlap with Derlin-1 and Derlin-2 may mask phenotypes in single-gene manipulation studies .

  • Solution: Consider combinatorial approaches targeting multiple Derlin family members when applicable.

Addressing these common technical issues proactively will improve experimental reliability and facilitate more accurate interpretation of Derlin-3 functional studies.

How can researchers differentiate between direct and indirect effects of Mouse Derlin-3 manipulation in experimental systems?

Distinguishing direct from indirect effects of Mouse Derlin-3 manipulation requires rigorous experimental design and careful controls:

• Substrate validation approaches:

  • Complementary protein-protein interaction studies (co-immunoprecipitation, proximity labeling)

  • In vitro reconstitution of degradation with purified components where feasible

  • Mutational analysis of putative recognition motifs in candidate substrates

  • Competition assays with established Derlin-3 substrates

• Temporal analysis:

  • Acute vs. chronic Derlin-3 manipulation to distinguish immediate from adaptive effects

  • Time-course experiments to establish sequence of molecular events

  • Pulse-chase studies to determine degradation kinetics for putative substrates

• Rescue experiments:

  • Complementation with wild-type Derlin-3 in knockdown/knockout systems

  • Domain-specific mutants to identify functional regions required for specific effects

  • Cross-rescue with other Derlin family members to assess specificity

• Systematic controls:

  • Parallel analysis of other ERAD components to distinguish Derlin-3-specific effects

  • Careful monitoring of UPR activation markers to account for secondary stress responses

  • Verification that observed phenotypes scale with the degree of Derlin-3 manipulation

• Downstream pathway inhibition:

  • Pharmacological or genetic inhibition of downstream effectors to block indirect effects

  • Proteasome inhibition to distinguish ERAD-dependent from ERAD-independent effects

These methodological approaches collectively enable more confident attribution of observed phenotypes to direct Derlin-3 functions versus secondary or compensatory effects.

What are the best practices for analyzing complex protein-protein interactions involving Mouse Derlin-3?

Analyzing the complex protein-protein interaction network of Mouse Derlin-3 requires specialized approaches that address the challenges of studying transmembrane ERAD components:

• Detergent selection for complex preservation:

  • Mild detergents like digitonin or CHAPSO better preserve native interactions

  • Comparative analysis with multiple detergent conditions can reveal detergent-sensitive interactions

  • Two-step solubilization protocols that capture both membrane and peripheral protein interactions

• Proximity-based interaction mapping:

  • BioID or APEX2 proximity labeling with Derlin-3 as the bait protein

  • Crosslinking mass spectrometry to capture transient interactions

  • Split reporter systems (e.g., split GFP) for monitoring specific interactions in living cells

• Co-immunoprecipitation strategies:

  • Reciprocal co-IP to confirm bidirectional interaction

  • Native vs. crosslinked conditions to distinguish stable from transient interactions

  • Competitive binding experiments to identify interaction domains

• Functional validation of interactions:

  • Dominant-negative competition assays

  • Mutation of putative interaction interfaces

  • Functional complementation between interaction partners

• Visualization approaches:

  • Super-resolution microscopy to visualize co-localization in membrane microdomains

  • FRET or BRET analysis for direct protein proximity measurement

  • Live-cell imaging to capture dynamic interaction patterns during ER stress

• Quantitative analysis methods:

  • SILAC or TMT labeling for quantitative interaction proteomics

  • Competition experiments with unlabeled proteins to assess binding affinity

  • Stoichiometry determination through quantitative mass spectrometry

These best practices enable comprehensive analysis of Derlin-3's interactions with both ERAD machinery components and substrate proteins while addressing the technical challenges inherent to membrane protein biochemistry.

What are the potential roles of Mouse Derlin-3 in metabolic regulation beyond glycolysis?

Emerging evidence suggests that Mouse Derlin-3 may have broader implications for metabolic regulation beyond its documented role in SLC2A1/GLUT1 degradation and glycolysis:

• Potential regulation of additional metabolic transporters: Given Derlin-3's role in SLC2A1 degradation, it may regulate other members of the SLC transporter family involved in amino acid, lipid, or ion transport. This broader regulatory role could position Derlin-3 as a master regulator of cellular nutrient uptake under stress conditions .

• Intersection with mTOR signaling: As a regulator of glucose transport, Derlin-3 may indirectly influence mTOR activation, which serves as a central regulator of cellular metabolism. This potential crosstalk could link ERAD function to broader metabolic adaptation pathways.

• Mitochondrial-ER crosstalk: The ER and mitochondria form specialized contact sites critical for cellular metabolism. Derlin-3's role in ER homeostasis may influence these contact sites and thereby affect mitochondrial function and oxidative phosphorylation.

• Lipid metabolism connections: ER stress affects lipid metabolism and vice versa. Derlin-3's function in alleviating ER stress may indirectly influence lipid synthesis, storage, and utilization pathways.

• Tissue-specific metabolic effects: Derlin-3's enriched expression in metabolically active tissues like pancreas and small intestine suggests potential specialized roles in tissue-specific metabolic processes, such as insulin secretion or nutrient absorption .

These potential regulatory roles represent promising areas for future investigation, particularly in contexts where metabolic adaptation intersects with ER stress responses.

How might advanced genomic engineering approaches advance Mouse Derlin-3 research?

Cutting-edge genomic engineering technologies offer new opportunities to advance Mouse Derlin-3 research beyond traditional approaches:

• Conditional and inducible Derlin-3 modulation:

  • Tissue-specific Cre-loxP systems for targeted deletion in specific cell types

  • Temporal control using tetracycline-responsive or other inducible promoters

  • Combinatorial approaches allowing simultaneous manipulation of multiple Derlin family members

• Precise genome editing for structure-function analysis:

  • CRISPR-Cas9 knock-in approaches to introduce specific mutations

  • Creation of domain swaps between Derlin family members to identify functional specificities

  • Introduction of reporter tags at endogenous loci to monitor expression without overexpression artifacts

• Single-cell approaches:

  • Single-cell RNA-seq to capture heterogeneity in Derlin-3 expression and response

  • Cell lineage tracing to monitor Derlin-3 expression dynamics during development or disease progression

  • Spatial transcriptomics to map Derlin-3 expression patterns in complex tissues

• In vivo functional imaging:

  • Development of activity-based sensors for real-time monitoring of Derlin-3 function

  • Integration with biosensors for ER stress to correlate Derlin-3 activity with cellular stress states

  • Whole-animal imaging to track Derlin-3 expression in disease models

• High-throughput screening platforms:

  • CRISPR activation/interference screens to identify regulators of Derlin-3 expression

  • Chemical screening approaches to identify small molecule modulators of Derlin-3 function

  • Synthetic genetic interaction screens to map functional relationships

These advanced approaches would enable more precise dissection of Derlin-3 functions in physiological contexts and accelerate the development of therapeutic strategies targeting ERAD pathways.

What interdisciplinary approaches could provide new insights into Mouse Derlin-3 functions?

Interdisciplinary research strategies offer unique opportunities to uncover novel aspects of Mouse Derlin-3 biology:

• Systems biology integration:

  • Network analysis incorporating transcriptomic, proteomic, and metabolomic data

  • Mathematical modeling of ERAD dynamics with Derlin-3 as a variable component

  • Machine learning approaches to identify patterns in large-scale datasets related to Derlin-3 function

• Structural biology and biophysics:

  • Cryo-electron microscopy of Derlin-3-containing complexes

  • Molecular dynamics simulations to understand Derlin-3 membrane interactions

  • Single-molecule studies of substrate translocation through ERAD channels

• Evolutionary biology perspectives:

  • Comparative analysis of Derlin family evolution across species

  • Identification of conserved functional motifs through phylogenetic approaches

  • Investigation of species-specific adaptations in Derlin-3 function

• Clinical research connections:

  • Translational studies correlating human DERL3 variants with disease susceptibility

  • Analysis of DERL3 expression in patient samples from various diseases

  • Development of Derlin-3-based biomarkers for stress adaptation capacity

• Bioengineering applications:

  • Development of synthetic biology tools utilizing Derlin-3 for controlled protein degradation

  • Biomaterial approaches for delivery of Derlin-3 modulators to specific tissues

  • Engineered cellular systems with tunable ERAD capacity for biotechnology applications

These interdisciplinary approaches would provide complementary perspectives on Derlin-3 biology and potentially reveal unexpected functions or applications beyond the current understanding of its role in ERAD and stress responses.