CCDC50 Antibody

What is CCDC50 and what are its primary biological functions?

CCDC50 is a multifunctional protein that serves several critical roles in cellular processes. Recent research has established CCDC50 as:

• A selective autophagy receptor that delivers K63 polyubiquitination-activated substrates for autophagic degradation

• A negative regulator of the type I interferon (IFN) signaling pathway initiated by RIG-I-like receptors (RLRs), which are sensors for RNA viruses

• An inhibitor of NLRP3 inflammasome activity by mediating autophagy

• A lysophagy receptor that promotes tumor growth by controlling lysosomal integrity and renewal

• An aggrephagy receptor that combats proteotoxic stress by clearing protein aggregates

• An effector of epidermal growth factor (EGF)-mediated cell signaling

• A protein involved in hearing loss when mutated (DFNA44)

The expression of CCDC50 can be enhanced by various stimuli, including viral infection, making it an important regulatory component in stress responses and cellular homeostasis .

What applications are CCDC50 antibodies validated for?

Based on extensive validation studies, CCDC50 antibodies are suitable for multiple research applications:

Most commercially available CCDC50 antibodies have been primarily validated with human samples, though some show cross-reactivity with mouse samples based on sequence homology .

What is the molecular weight of CCDC50 and why might there be discrepancies in observed sizes?

CCDC50 presents an interesting case of discrepancy between theoretical and observed molecular weights:

• Calculated molecular weight: 56 kDa (based on its 482 amino acid sequence)

• Commonly observed molecular weight: 36-38 kDa in Western blot analysis

This significant discrepancy may be attributed to:

• Post-translational modifications affecting protein mobility in SDS-PAGE

• Protein processing or proteolytic cleavage events

• Alternative splicing resulting in different isoforms

• Structural features affecting migration patterns

When performing Western blot analysis, researchers should expect to observe CCDC50 at approximately 36-38 kDa rather than at its calculated molecular weight. This characteristic can serve as a verification point for antibody specificity .

What are the recommended protocols for using CCDC50 antibodies in Western blot analysis?

For optimal Western blot analysis of CCDC50, follow these validated protocols:

Sample preparation:

• Cell lysates should be prepared from cell lines known to express CCDC50 (e.g., A549, HeLa, HEK-293, HepG2)

• Load approximately 30 μg of total protein per lane

Gel electrophoresis and transfer:

• 10% SDS-PAGE has been successfully used for separating CCDC50

• Transfer to PVDF or nitrocellulose membranes using standard protocols

Antibody incubation:

• Primary antibody dilutions ranging from 1:5000 to 1:100000 have been reported

• For example, ab127169 has been used successfully at 1:5000 dilution

• Primary antibody incubation should be performed overnight at 4°C or for 1-2 hours at room temperature

• Use appropriate HRP-conjugated secondary antibody

Detection:

• Visualize using enhanced chemiluminescence (ECL)

• Look for bands at approximately 36-38 kDa, despite the calculated molecular weight being 56 kDa

A properly executed Western blot should show clear bands for CCDC50 in positive control samples such as 293T, A431, HeLa, and A549 cell lysates .

How can researchers validate CCDC50 antibody specificity in autophagy-related experiments?

Validating CCDC50 antibody specificity in autophagy-related research requires multiple complementary approaches:

Genetic controls:

• Generate CCDC50-KO cell lines using CRISPR/Cas9 technology, which should show absence of signal

• Implement inducible shRNA systems to create controlled reduction of CCDC50 expression

• Include wildtype controls alongside knockdown/knockout systems

Functional validation:

• Verify that antibody-detected CCDC50 colocalizes with known autophagy markers (LC3, GABARAP)

• Confirm interaction with LC3 through co-immunoprecipitation or structural analysis

• Verify recognition of K63-polyubiquitinated substrates

Autophagy-specific validation:

• Treat cells with autophagy inducers (starvation, rapamycin) and inhibitors (chloroquine)

• Validate that CCDC50 behavior corresponds with its role as an autophagy receptor

• Confirm association with known CCDC50 substrates (damaged lysosomes, protein aggregates)

Technical considerations:

• Use multiple antibodies targeting different epitopes when possible

• Include positive control cell lines with confirmed CCDC50 expression

• Perform both biochemical (Western blot) and imaging (immunofluorescence) validation

How should researchers approach studying CCDC50's role in the regulation of innate immune responses?

When investigating CCDC50's role in innate immunity, particularly its function as a negative regulator of type I interferon responses, consider these experimental strategies:

Model systems selection:

• Human cell lines: THP-1 monocytic cells have shown CCDC50 upregulation during viral infection

• Primary immune cells: Bone marrow-derived macrophages (BMDMs) and dendritic cells (BMDCs) are relevant models

• Mouse models: Ccdc50-/- mice have been generated to study in vivo effects

Experimental stimuli:

• RNA viruses: SeV, VSV, EMCV have been validated to induce CCDC50 expression

• NLRP3 inflammasome activators: ATP, nigericin, silica, SiO2

• Bacterial stimuli: Listeria monocytogenes and Salmonella typhimurium

Critical readouts:

• Cytokine expression: Measure IL-1β, IL-6, TNFα mRNA and protein levels

• Inflammasome activation: Monitor pro-caspase-1 cleavage and IL-1β maturation

• Type I IFN pathway: Assess IFN-β production and downstream signaling

• RLR degradation: Track RIG-I/MDA5 levels and ubiquitination status

Essential controls:

• CCDC50 expression verification: Confirm knockdown/knockout efficiency

• Pathway-specific controls: Include controls for RIG-I, MDA5, and inflammasome components

• Temporal analysis: Assess responses at multiple timepoints post-stimulation

The dynamics of CCDC50 expression during immune activation are crucial - viral infection enhances CCDC50 expression, creating a negative feedback loop that limits excessive inflammatory responses .

What approaches are most effective for studying CCDC50's interactions with ubiquitinated proteins?

CCDC50 specifically recognizes K63-polyubiquitinated substrates. To study these interactions effectively:

Biochemical approaches:

• Co-immunoprecipitation: Use anti-CCDC50 antibodies to pull down complexes, then immunoblot with K63-linkage specific antibodies

• Reciprocal co-IP: Immunoprecipitate K63-polyubiquitinated proteins and probe for CCDC50

• In vitro binding assays: Test direct binding between purified CCDC50 and synthetic K63-ubiquitin chains

Structural analysis:

• Crystal structure determination: The association of CCDC50 with ubiquitin has been confirmed by crystal structure analysis

• Domain mapping: Identify which CCDC50 domains are essential for K63-ubiquitin recognition

• Mutagenesis studies: Create point mutations in putative ubiquitin-binding domains to identify critical residues

Microscopy techniques:

• Co-localization studies: Visualize CCDC50 recruitment to ubiquitinated substrates

• Live-cell imaging: Monitor real-time recruitment of fluorescently tagged CCDC50 to ubiquitinated substrates

• Proximity ligation assay: Detect protein-protein interactions with high sensitivity and spatial resolution

Substrate specificity analysis:

• RLR ubiquitination: Assess CCDC50 recognition of K63-polyubiquitinated RIG-I/MDA5

• Damaged lysosomes: Study recognition of ubiquitinated proteins on damaged lysosomes

• Protein aggregates: Analyze binding to ubiquitinated protein aggregates

Understanding the specificity of CCDC50 for K63-polyubiquitinated substrates is crucial, as this is the molecular basis for its selective autophagy receptor function .

How can researchers distinguish between CCDC50's roles in different selective autophagy pathways?

CCDC50 functions in multiple selective autophagy pathways, including RLR-mediated autophagy, lysophagy, and aggrephagy. To differentiate these functions:

Pathway-specific induction:

• RLR-mediated autophagy: RNA virus infection (SeV, VSV, EMCV)

• Lysophagy: Lysosome-damaging agents like LLOMe

• Aggrephagy: Proteotoxic stressors or expression of aggregation-prone proteins

Substrate-specific markers:

• RLR pathway: Monitor RIG-I/MDA5 ubiquitination and degradation

• Lysophagy: Track galectin-3 recruitment to damaged lysosomes

• Aggrephagy: Assess clearance of polyubiquitinated protein aggregates

Co-localization analysis:

• Triple labeling: Visualize CCDC50 with LC3 and pathway-specific markers

• Sequential recruitment: Determine temporal dynamics of CCDC50 recruitment to different substrates

• Subcellular localization: Map where different interactions occur within the cell

Functional readouts:

• RLR pathway: Measure type I IFN production and antiviral responses

• Lysophagy: Assess lysosomal integrity, ROS levels, and tumor growth capacity

• Aggrephagy: Evaluate proteostasis and neuronal cell survival

This multi-faceted approach allows for precise characterization of CCDC50's distinct roles in each selective autophagy pathway.

How should researchers approach studying the relationship between CCDC50 expression and tumor progression in melanoma?

CCDC50 is associated with melanoma progression and poor prognosis. To investigate this relationship:

In vitro experimental design:

• Cell line selection: A375 (human) and B16-F10 (mouse) melanoma cells are validated models

• CCDC50 modulation: Generate stable CCDC50-knockdown lines using shRNA or CRISPR/Cas9

• Functional assays: Assess proliferation, migration, invasion, and colony formation

• Mechanism studies: Evaluate lysosomal integrity, autophagy flux, and ROS production

In vivo model systems:

• Subcutaneous xenograft models: Implant CCDC50-expressing versus CCDC50-depleted melanoma cells

• Metastasis models: Use intravenous injection for lung colonization assessment

• Inducible systems: Employ doxycycline-inducible shRNA to modulate CCDC50 after tumor establishment

• Analysis parameters: Measure tumor volume, weight, metastatic nodules, and survival times

Clinical correlation analysis:

• TCGA data mining: Analyze CCDC50 expression in SKCM datasets

• Expression correlation: Compare CCDC50 levels between benign nevi, primary melanoma, and metastatic melanoma

• Prognostic value: Correlate expression with patient outcomes and metastatic progression

Therapeutic implications:

• Drug combinations: Test CCDC50 targeting in combination with BRAF inhibitors

• According to research, "the combination of CCDC50 ablation and BRAF V600E inhibition achieved an additive effect in accelerating apoptosis of melanoma cells in comparison with the single treatment alone"

What considerations are important when studying CCDC50's role in hearing loss models?

CCDC50 mutations are associated with DFNA44 hereditary hearing loss. For effective research in this area:

Model selection:

• Mouse models: Two loss-of-function Ccdc50 mutant mouse lines have been analyzed

• Age considerations: Mice up to 10 weeks old have been used, as some develop hydrocephalus at later ages

• Mutation-specific models: Create models replicating specific human mutations (e.g., c.866_873dup, c.828_858del)

Antibody considerations:

• Epitope selection: Custom-made antibodies targeting both N-terminal (RIQEKKDEDIARLL) and C-terminal (NQHSTTWHLPKSES) regions have been successfully used

• Mutation awareness: For truncated proteins, use antibodies targeting epitopes before the truncation site

• Specificity validation: Verify antibody specificity in the mouse strain being used

Experimental techniques:

• Site-directed mutagenesis: Generate mutations found in human patients using kits like Quick Change II

• Immunocytochemistry: Protocols using 4% paraformaldehyde fixation followed by permeabilization with 0.5% Triton X-100 have been effective

• Nuclear counterstaining: Hoechst 33342 at 1 μg/ml provides clear visualization of nuclei alongside CCDC50 staining

Mechanistic analysis:

• Expression patterns: Analyze CCDC50 expression across different cochlear cell types

• Protein localization: Determine whether mutations alter subcellular distribution

• Functional correlation: Connect molecular findings with audiological assessments

Understanding the exact mechanisms by which CCDC50 mutations lead to hearing loss requires careful consideration of protein expression, localization, and function in cochlear tissues .

What is known about CCDC50's unique binding properties with LC3 in autophagy?

CCDC50 exhibits unique binding characteristics with LC3 that distinguish it from other autophagy receptors:

Dual binding capability:

• CCDC50 can bind to both the LIR-docking site (LDS) and the UIM-docking site (UDS) of LC3

• "In contrast to other known autophagic cargo receptors that associate with either the LIR-docking site (LDS) or the UIM-docking site (UDS) of LC3, CCDC50 can bind to both LDS and UDS, representing a new type of cargo receptor"

Structural confirmation:

• Crystal structure analysis has confirmed CCDC50's association with LC3

• This dual binding capability likely enhances substrate recognition efficiency

Functional significance:

• The unique binding properties may explain CCDC50's versatility in recognizing different autophagic cargoes

• This dual binding may enhance the efficiency of substrate delivery to autophagosomes

• The mechanism potentially allows CCDC50 to function as a receptor in multiple selective autophagy pathways

Research implications:

• CCDC50 represents a novel class of autophagy receptors with unique binding properties

• Understanding these binding characteristics may inform the development of tools to modulate selective autophagy

• This knowledge contributes to our broader understanding of how autophagy receptors recognize and deliver cargo

This distinctive binding profile sets CCDC50 apart from other known autophagy receptors and likely contributes to its versatile roles in multiple selective autophagy pathways .

How does CCDC50 contribute to protection against neurodegenerative processes?

Recent research has identified CCDC50 as a potential protective factor in neurodegenerative conditions:

Aggrephagy function:

• CCDC50 is highly expressed in brain tissue and functions as an aggrephagy receptor

• "CCDC50, a highly expressed autophagy receptor in brain, is recruited to proteotoxic stresses-induced polyubiquitinated protein aggregates and ectopically expressed aggregation-prone proteins"

• It recognizes and clears cytotoxic protein aggregates through autophagy

Neuroprotective effects:

• "The ectopic expression of CCDC50 increases the tolerance to stress-induced proteotoxicity and hence improved cell survival in neuron cells"

• CCDC50 deficiency leads to accumulation of lipid deposits and polyubiquitinated protein conjugates in aging brains

• One-year-old CCDC50-deficient mice show accumulation of protein aggregates

Relevance to neurodegenerative diseases:

• Protein aggregation is implicated in multiple neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis

• By combating proteotoxic stress, CCDC50 may play a protective role against these conditions

• "Our study illustrates how aggrephagy receptor CCDC50 combats proteotoxic stress for the benefit of neuronal cell survival, thus suggesting a protective role in neurotoxic proteinopathy"

Future therapeutic implications:

• Enhancing CCDC50 function could potentially improve clearance of protein aggregates

• CCDC50-based therapeutic strategies might help mitigate neurodegenerative processes

• Understanding CCDC50's role could inform development of novel approaches to treating proteinopathies

This emerging research highlights CCDC50's importance in maintaining neuronal proteostasis and suggests potential therapeutic applications in neurodegenerative diseases .