DNAJB11 Antibody

What is DNAJB11 and why is it important in research?

DNAJB11 (DnaJ homolog subfamily B member 11) is an evolutionarily conserved member of the DNAJ/HSP40 family of proteins that regulates molecular chaperone activity by stimulating ATPase activity. It serves as a co-chaperone for HSPA5 (also known as GRP78 or BiP), binding directly to both unfolded proteins destined for ER-associated degradation (ERAD) and nascent unfolded peptide chains . Recent research has identified DNAJB11 as a critical factor in kidney disease pathogenesis, particularly in atypical forms of autosomal dominant polycystic kidney disease (ADPKD) . DNAJB11 mutations result in non-enlarged cystic kidneys and progressive renal failure, representing a phenotypic hybrid between ADPKD and autosomal dominant tubulointerstitial kidney disease (ADTKD) .

What are the key structural features of DNAJB11 that antibodies typically target?

DNAJB11 contains several distinct domains that antibodies may target:

• A conserved 70-amino acid J domain, typically located at the N-terminus

• A glycine/phenylalanine (G/F)-rich region

• A C-terminal cysteine-rich region

Commercial antibodies are available targeting various regions including the N-terminal domain, internal regions, and C-terminal domain . When selecting an antibody, researchers should consider which domain is most relevant to their study, as different domains may be involved in distinct protein interactions or functions.

What species reactivity can I expect from commercially available DNAJB11 antibodies?

Most commercial DNAJB11 antibodies demonstrate cross-reactivity with human, mouse, and rat samples . This cross-reactivity stems from the high conservation of DNAJB11 across mammalian species. Specific reactivity profiles from available antibodies include:

Always validate the antibody in your specific experimental system regardless of the manufacturer's claims .

Which applications are DNAJB11 antibodies most reliable for in kidney disease research?

DNAJB11 antibodies have been successfully employed in multiple applications in kidney disease research:

• Western blotting (WB): Particularly effective for quantifying DNAJB11 expression levels and detecting changes in protein processing. Recommended dilutions range from 1:1000 to 1:6000 .

• Immunohistochemistry (IHC): Valuable for examining DNAJB11 localization in kidney tissues, particularly in cystic regions. This technique can reveal altered distribution patterns in disease states. Recommended dilutions range from 1:20 to 1:200 .

• Immunoprecipitation (IP): Useful for studying DNAJB11 interaction partners, particularly its association with polycystin-1 (PC1). Typically requires 0.5-4.0 μg antibody for 1.0-3.0 mg of total protein lysate .

• Immunofluorescence (IF): Excellent for co-localization studies with other ER proteins or polycystins. Recommended dilutions range from 1:10 to 1:100 .

For kidney disease research specifically, combining IHC with WB provides robust data on both the localization and expression levels of DNAJB11 in disease models .

How should I design experiments to investigate DNAJB11's role in polycystin-1 processing?

To investigate DNAJB11's role in polycystin-1 (PC1) processing:

• Cell model selection: Use renal epithelial cell lines (like RCTE cells) with CRISPR/Cas9-mediated DNAJB11 knockout .

• Experimental approach:

  • Compare PC1 cleavage and maturation between wild-type and DNAJB11-null cells

  • Analyze the ratio of PC1 C-terminal fragment to immature full-length protein

  • Assess trafficking of PC1 using subcellular fractionation or immunofluorescence

• Controls:

  • Include positive controls (normal PC1 processing in wild-type cells)

  • Use rescue experiments with DNAJB11 re-expression to confirm specificity

  • Examine other cystoproteins to determine specificity of the effect for PC1

• Analysis methods:

  • Western blotting with antibodies against different PC1 domains to monitor cleavage events

  • Pulse-chase experiments to track PC1 maturation kinetics

  • Co-immunoprecipitation to detect DNAJB11-PC1 interactions

Research has demonstrated that DNAJB11 loss results in a profound defect in PC1 cleavage, providing a mechanistic link between DNAJB11 mutations and cystic kidney disease .

What controls should be included when using DNAJB11 antibodies in immunohistochemistry of kidney tissues?

When performing immunohistochemistry with DNAJB11 antibodies on kidney tissues, include these essential controls:

• Negative controls:

  • Primary antibody omission (tissue sections incubated with antibody diluent only)

  • Isotype controls (non-specific IgG of the same species and concentration)

  • DNAJB11 knockout or knockdown tissues (if available)

  • Peptide competition assay (pre-incubating the antibody with immunizing peptide)

• Positive controls:

  • Known DNAJB11-expressing tissues (liver tissue shows reliable expression)

  • Serial dilutions to establish optimal antibody concentration

  • Alternative fixation methods to ensure epitope accessibility

• Technical considerations:

  • For human ovary tumor tissue (a validated positive control), use TE buffer pH 9.0 for antigen retrieval

  • Alternative antigen retrieval may be performed with citrate buffer pH 6.0

  • Test multiple antibody dilutions (starting with 1:20-1:200 range)

• Validation approaches:

  • Correlation with western blot results from the same samples

  • Comparison of staining patterns using antibodies targeting different DNAJB11 epitopes

  • Double-staining with ER markers to confirm expected subcellular localization

What are common pitfalls when using DNAJB11 antibodies in western blotting and how can they be addressed?

Common pitfalls and solutions when using DNAJB11 antibodies in western blotting:

• Weak or absent signal:

  • Potential cause: Insufficient protein expression, degradation, or inadequate antibody concentration

  • Solution: Increase antibody concentration (try 1:1000 dilution initially), use fresh lysates with protease inhibitors, and confirm DNAJB11 expression in your sample type (positive controls like HeLa cells, mouse liver tissue, or HepG2 cells show reliable expression)

• Multiple bands:

  • Potential cause: Cross-reactivity, protein degradation, or post-translational modifications

  • Solution: Use more stringent washing conditions, verify against DNAJB11 knockout samples, and note that the expected molecular weight is 41 kDa but the observed weight is typically 40 kDa

• Variable results across experiments:

  • Potential cause: Inconsistent transfer, sample loading, or antibody incubation

  • Solution: Normalize to housekeeping proteins, use standardized protocols with precise timing, and consider overnight primary antibody incubation at 4°C

• High background:

  • Potential cause: Insufficient blocking, excessive antibody concentration, or inadequate washing

  • Solution: Increase blocking time (minimum 1 hour at room temperature), optimize antibody dilution (typically 1:1000-1:6000), and perform additional washing steps with 0.1% PBST

How can I optimize immunofluorescence protocols for detecting DNAJB11 in renal epithelial cells?

To optimize immunofluorescence detection of DNAJB11 in renal epithelial cells:

• Fixation optimization:

  • Test both paraformaldehyde (4%, 10-15 minutes) and methanol (-20°C, 10 minutes) fixation

  • For ER proteins like DNAJB11, paraformaldehyde often preserves structure better

  • Include permeabilization steps with 0.1-0.3% Triton X-100 after PFA fixation

• Antibody optimization:

  • Start with a 1:50 dilution for primary antibody (range: 1:10-1:100)

  • Extend primary antibody incubation time (overnight at 4°C)

  • Use fluorophore-conjugated secondary antibodies appropriate for your microscopy system

• Signal enhancement strategies:

  • Include 0.1% saponin in antibody diluent to improve access to ER proteins

  • Use signal amplification systems for low-abundance targets

  • Consider tyramide signal amplification for very weak signals

• Background reduction:

  • Extend blocking time (2 hours with 5% normal serum from secondary antibody host species)

  • Include 0.1-0.3% Triton X-100 and 1% BSA in blocking buffer

  • Perform additional washing steps between antibody incubations

• Co-staining recommendations:

  • Co-stain with established ER markers (calnexin, PDI, or BiP/GRP78)

  • When examining PC1 interaction, co-stain with PC1 antibodies

  • Use confocal microscopy to better resolve ER localization

Positive controls should include HepG2 cells, which reliably express detectable levels of DNAJB11 .

How can I address non-specific staining issues with DNAJB11 antibodies in immunohistochemistry?

To address non-specific staining with DNAJB11 antibodies in immunohistochemistry:

• Optimize antigen retrieval:

  • For DNAJB11, TE buffer pH 9.0 is recommended as the primary method

  • Alternative methods include citrate buffer pH 6.0

  • Test both heat-induced (pressure cooker, 95-121°C) and enzymatic retrieval methods

• Blocking optimizations:

  • Increase blocking time (30 minutes to 2 hours)

  • Use both protein blocking (5% normal serum or 3% BSA) and avidin-biotin blocking if using biotin-based detection systems

  • Consider adding 0.1% Triton X-100 to blocking buffer for better penetration

• Antibody dilution and incubation:

  • Test a dilution series (1:20, 1:50, 1:100, 1:200) to determine optimal concentration

  • Extend primary antibody incubation (overnight at 4°C)

  • Reduce secondary antibody concentration if background persists

• Detection system considerations:

  • Switch between different detection systems (HRP-polymer vs. avidin-biotin complex)

  • Reduce DAB development time to minimize background

  • Include additional washing steps (minimum 3×5 minutes) between incubations

• Validation approaches:

  • Perform peptide competition assays

  • Use multiple antibodies targeting different epitopes of DNAJB11

  • Apply the same protocol to known positive (human ovary tumor) and negative control tissues

How should I interpret differences in DNAJB11 localization between normal and cystic kidney tissues?

When interpreting differences in DNAJB11 localization between normal and cystic kidney tissues:

• Normal localization pattern:

  • DNAJB11 typically shows diffuse ER localization in tubular epithelial cells

  • In proximal tubules, DNAJB11 may show more prominent staining due to extensive ER networks

  • Co-localization with other ER markers should be evident

• Altered patterns in cystic tissues:

  • Decreased expression: May indicate haploinsufficiency in DNAJB11 mutation carriers

  • Altered distribution: Redistribution from perinuclear to peripheral patterns may suggest ER stress

  • Cyst-specific changes: Focus on comparing DNAJB11 staining in cystic versus non-cystic tubules in the same sample

• Interpretative framework:

  • Changes in DNAJB11 localization should be interpreted in context with ER stress markers (BiP/GRP78, XBP1s, ATF6α)

  • Consider whether alterations reflect primary disease mechanisms or secondary responses

  • Correlate with PC1 processing/localization to establish functional relationships

• Research implications:

  • Altered DNAJB11 localization in specific tubular segments (proximal vs. distal) may explain the predominance of proximal tubule cysts in DNAJB11-associated disease

  • Changes in co-localization with PC1 could support the mechanistic link between DNAJB11 mutations and defective PC1 processing

How do DNAJB11 expression patterns differ between classical ADPKD and DNAJB11-associated kidney disease?

Key differences in DNAJB11 expression patterns between classical ADPKD and DNAJB11-associated kidney disease:

• Cellular distribution:

  • Classical ADPKD: DNAJB11 expression is typically preserved with normal ER distribution

  • DNAJB11-associated disease: May show reduced expression or altered distribution depending on the specific mutation

• Tubular segment involvement:

  • Classical ADPKD: Cysts arise from multiple tubular segments with no strong preference

  • DNAJB11-associated disease: Cysts predominantly originate from proximal tubules based on mouse model studies

• Relationship to fibrosis:

  • Classical ADPKD: Fibrosis typically correlates with disease progression and cyst burden

  • DNAJB11-associated disease: Shows early and possibly cyst-independent interstitial fibrosis, creating a phenotypic overlap with ADTKD

• Interaction with PC1:

  • Classical ADPKD: Direct PC1/PC2 mutations with normal DNAJB11-assisted processing of remaining normal protein

  • DNAJB11-associated disease: Primary defect in PC1 processing machinery leading to defective GPS cleavage and maturation of PC1

The ability to distinguish these patterns has important implications for differential diagnosis and understanding disease mechanisms, as DNAJB11-associated disease represents a phenotypic hybrid between ADPKD and ADTKD .

What evidence supports a mechanistic link between DNAJB11 and polycystin-1 processing in kidney disease?

Multiple lines of evidence support the mechanistic link between DNAJB11 and polycystin-1 (PC1) processing:

• Biochemical evidence:

  • DNAJB11 loss results in a profound defect in PC1 cleavage based on in vitro studies

  • This manifests as altered ratio of PC1 C-terminal fragment to immature full-length protein

  • The effect appears specific to PC1, as other cystoproteins were unaffected in DNAJB11-null cells

• Genetic evidence:

  • Conditional loss of DNAJB11 in renal tubular epithelium results in PC1 dosage-dependent kidney cysts

  • This defines a shared mechanism with classical ADPKD caused by PKD1 mutations

  • Mouse models demonstrate that the timing of DNAJB11 inactivation strongly influences disease severity

• Structural/functional relationship:

  • DNAJB11, as an ER co-chaperone, likely assists in the proper folding of PC1

  • Specifically, DNAJB11 appears to be required for GPS (G-protein coupled receptor proteolytic site) cleavage of PC1

  • This cleavage is essential for PC1 maturation and function

• Clinical correlation:

  • Patients with DNAJB11 mutations develop a kidney disease phenotype that shares features with both ADPKD and ADTKD

  • The intermediate phenotype (normal-sized cystic kidneys) suggests partial loss of polycystin function rather than complete absence

These findings collectively establish DNAJB11 as a critical mediator of PC1 processing, with mutations leading to an atypical form of ADPKD through defective PC1 maturation .

How can proteomics approaches be used to identify novel DNAJB11 interaction partners in kidney disease?

Proteomic approaches to identify novel DNAJB11 interaction partners in kidney disease:

• Proximity-based labeling methods:

  • BioID/TurboID: Fuse a biotin ligase to DNAJB11 to biotinylate proximal proteins in living cells

  • APEX2: Use an engineered peroxidase fused to DNAJB11 to label nearby proteins with biotin

  • These methods capture transient interactions and can be performed in appropriate kidney cell lines or in vivo using transgenic mice

• Immunoprecipitation-mass spectrometry (IP-MS):

  • Use anti-DNAJB11 antibodies (0.5-4.0 μg for 1.0-3.0 mg of total protein) to pull down DNAJB11 complexes

  • Perform in both normal and cystic kidney tissues/cells

  • Compare interactomes to identify disease-specific interactions

  • Include crosslinking steps (DSP or formaldehyde) to capture transient interactions

• Comparative proteomics:

  • Compare the proteomes of wild-type, DNAJB11-deficient, and PKD1-deficient cells

  • This approach has revealed common and distinct pathways and dysregulated proteins

  • Results provide a foundation for understanding phenotypic differences between different forms of ADPKD

• Dynamic interaction mapping:

  • Perform IP-MS under various conditions (ER stress, unfolded protein response activation)

  • Use pulse-chase labeling combined with MS to track temporal dynamics of interactions

  • These approaches can reveal condition-specific interactions relevant to disease states

Recent proteomic studies comparing DNAJB11-deficient and PKD1-deficient cells have identified both overlapping and distinct pathways, providing insight into the molecular mechanisms underlying different forms of ADPKD .

What are the most effective methods for assessing DNAJB11's role in the unfolded protein response during kidney disease progression?

Methods for assessing DNAJB11's role in the unfolded protein response (UPR) during kidney disease:

• UPR activation markers assessment:

  • Western blotting for key branch-specific markers:

    • IRE1α branch: XBP1s (spliced XBP1)

    • ATF6 branch: Cleaved ATF6α

    • PERK branch: CHOP, phospho-eIF2α

  • qRT-PCR for UPR target genes (HSPA5/BiP, DDIT3/CHOP, ERdj4, EDEM1)

  • RNA-seq to capture global transcriptional changes related to UPR

• UPR induction experiments:

  • Treat wild-type and DNAJB11-null cells with UPR inducers (tunicamycin, thapsigargin)

  • Compare responses to identify DNAJB11-dependent aspects of UPR

  • Current evidence suggests DNAJB11 loss does not activate the UPR, drawing a fundamental contrast with ADTKD pathogenesis

• In vivo UPR assessment:

  • Analyze UPR markers in kidney tissues from DNAJB11 mouse models at different disease stages

  • Use UPR reporter mice crossed with DNAJB11-deficient mice

  • Apply spatial transcriptomics or single-cell RNA-seq to identify cell-specific UPR responses

• Functional assays:

  • Assess ER stress via calcium imaging in DNAJB11-deficient cells

  • Monitor protein synthesis rates using puromycin incorporation assays

  • Measure ER-associated degradation (ERAD) efficiency using model substrates

Importantly, research has shown that DNAJB11 mouse models show no evidence of UPR activation or cyst-independent fibrosis, which is a fundamental distinction from typical ADTKD pathogenesis . This suggests that in DNAJB11-associated disease, fibrosis may represent an exaggerated response to polycystin-dependent cysts rather than primary UPR activation .

What genetic models best recapitulate human DNAJB11-associated kidney disease for antibody validation and mechanism studies?

Optimal genetic models for studying DNAJB11-associated kidney disease:

• Mouse models:

  • Germline Dnajb11-null mice: These mice are live-born at below Mendelian ratios and die around weaning age with cystic kidneys

  • Conditional Dnajb11 knockout mice: More versatile, allowing tissue-specific and temporal control of DNAJB11 inactivation

    • Pax8-rtTA/TetO-Cre system for inducible deletion in renal tubular epithelium

    • Emx1-Cre or Six2-Cre for developmental stage-specific deletion

  • Dnajb11 heterozygous mice: Better model for the autosomal dominant inheritance in humans

• Timing considerations:

  • The timing of DNAJB11 inactivation strongly influences disease severity

  • Conditional models allow investigation of early versus late deletion effects

  • This approach has shown that cyst formation begins in utero in complete knockout models

• Cellular models:

  • CRISPR/Cas9-engineered renal epithelial cell lines:

    • RCTE cells with DNAJB11 exon 3 targeting

    • Develop isogenic cell lines with different DNAJB11 mutations found in patients

  • Patient-derived iPSCs differentiated to kidney organoids:

    • Allows study of human-specific aspects of the disease

    • Can incorporate patient-specific genetic backgrounds

• Recommended validation approaches:

  • Confirm DNAJB11 knockout/knockdown efficiency using validated antibodies

  • Verify PC1 processing defects as a functional readout

  • Examine cell-type specificity by combining with lineage markers for proximal tubules, which show predominant cyst formation in DNAJB11-deficient mice

• Key findings from genetic models:

  • Biallelic loss of Dnajb11 causes cystic kidney disease and fibrosis, mirroring human disease characteristics

  • Cysts predominantly originate from proximal tubules, distinguishing it from classical ADPKD

  • Impaired PC1 GPS cleavage appears to be a key mechanism underlying cyst formation

These models provide complementary systems for both antibody validation and mechanistic studies of DNAJB11's role in kidney disease .

How might single-cell analysis techniques enhance our understanding of DNAJB11 function in heterogeneous kidney tissues?

Single-cell analysis techniques offer powerful approaches to understand DNAJB11 function in heterogeneous kidney tissues:

• Single-cell RNA sequencing (scRNA-seq):

  • Reveals cell type-specific expression patterns of DNAJB11 across nephron segments

  • Identifies transcriptional changes in DNAJB11-expressing cells during disease progression

  • Can detect compensatory responses in specific cell populations following DNAJB11 mutation

  • Particularly valuable for understanding why proximal tubules are predominantly affected in DNAJB11-associated disease

• Single-cell proteomics:

  • Emerging techniques like SCoPE-MS (Single Cell ProtEomics by Mass Spectrometry) can quantify DNAJB11 protein levels at single-cell resolution

  • Enables correlation of DNAJB11 abundance with other ER chaperones in specific cell types

  • Can reveal post-transcriptional regulation not captured by RNA analysis

• Spatial transcriptomics/proteomics:

  • Combines single-cell resolution with spatial information critical for understanding cyst formation

  • Technologies like Visium, MERFISH, or imaging mass cytometry preserve the tissue context

  • Can reveal spatial relationships between DNAJB11 expression, UPR activation, and early cystic changes

• CyTOF with DNAJB11 antibodies:

  • Mass cytometry allows simultaneous detection of dozens of proteins at single-cell resolution

  • Can include antibodies against DNAJB11, PC1, ER stress markers, and cell type-specific proteins

  • Enables creation of comprehensive cellular hierarchies in normal and diseased kidneys

These approaches will help clarify why DNAJB11 mutations preferentially affect certain tubular segments and how heterogeneous cellular responses contribute to the unique disease phenotype .

What therapeutic implications arise from understanding DNAJB11's role in polycystin-1 processing?

Understanding DNAJB11's role in PC1 processing reveals several therapeutic implications:

• Small molecule chaperone approaches:

  • Chemical chaperones that facilitate PC1 folding and maturation might bypass the need for DNAJB11

  • Compounds like 4-phenylbutyrate (4-PBA) or tauroursodeoxycholic acid (TUDCA) could be repurposed as they enhance protein folding in the ER

  • Design of PC1-specific pharmacological chaperones based on structural understanding of PC1-DNAJB11 interaction

• Proteasome modulation strategies:

  • If misfolded PC1 accumulation contributes to pathology, proteasome activators could enhance clearance

  • Conversely, selective proteasome inhibition might preserve partially functional PC1 that would otherwise be degraded

  • This approach requires careful antibody-based monitoring of PC1 processing intermediates

• Gene therapy approaches:

  • AAV-mediated DNAJB11 gene delivery to kidney tubules

  • CRISPR base editing to correct specific DNAJB11 mutations

  • Approaches enhancing wild-type DNAJB11 expression in heterozygous mutation carriers

• Downstream pathway targeting:

  • Since impaired PC1 processing affects similar downstream pathways as in classical ADPKD, therapies developed for ADPKD (like vasopressin V2 receptor antagonists) may be effective

  • New therapeutic targets may emerge from comparative proteomic studies of DNAJB11- and PKD1-deficient cells

• Personalized medicine implications:

  • Antibody-based assays could help stratify patients based on the degree of PC1 processing defects

  • This could guide selection of appropriate therapeutic strategies targeting either PC1 processing or downstream consequences

The mechanistic link between DNAJB11 and PC1 provides a rationale for exploring these therapeutic avenues, potentially benefiting patients with both DNAJB11-associated disease and classical ADPKD .

How can multi-omics approaches combined with DNAJB11 antibody-based studies advance our understanding of atypical polycystic kidney disease?

Multi-omics approaches combined with DNAJB11 antibody-based studies can synergistically advance our understanding of atypical polycystic kidney disease:

• Integrated proteogenomic analysis:

  • Combine genome/exome sequencing with antibody-based proteomics to correlate DNAJB11 variants with protein expression and modification

  • Apply to both DNAJB11 mutation carriers and classical ADPKD patients to identify shared molecular signatures

  • Use DNAJB11 antibodies for protein-level validation of genomic findings

• Epigenome-transcriptome-proteome integration:

  • Map epigenetic modifications controlling DNAJB11 expression using ChIP-seq

  • Correlate with transcriptional changes (RNA-seq) and protein-level alterations (proteomics)

  • Identify regulatory networks controlling DNAJB11 and its client proteins

  • Validate key regulatory relationships using antibody-based ChIP, RNA-IP, or proximity ligation assays

• Metabolomics integration:

  • Correlate DNAJB11 expression/localization with metabolomic profiles in kidney tissues

  • Identify metabolic signatures distinguishing DNAJB11-associated disease from classical ADPKD

  • These signatures may reveal functional consequences of altered protein homeostasis in the ER

• Systems biology frameworks:

  • Construct comprehensive network models incorporating various omics data

  • Use antibody-based validation of key network nodes and interactions

  • Identify potential therapeutic targets through network perturbation analysis

  • Current research has already identified common and distinct pathways between DNAJB11- and PKD1-deficient cells that can be expanded upon

• Translational applications:

  • Develop diagnostic algorithms integrating genetic, transcriptomic, and proteomic markers

  • Create prognostic models predicting disease progression based on multi-omics signatures

  • Design targeted therapies addressing specific molecular mechanisms identified through integrated analysis