DIRAS2 Antibody

What is DIRAS2 and what are its key molecular characteristics?

DIRAS2 belongs to a distinct branch of the Ras superfamily of monomeric GTPases. Unlike other Ras family proteins, DIRAS2 displays low GTPase activity and exists predominantly in the GTP-bound form . It has unique biochemical properties compared to other Ras kinases, as it fails to activate the MAP kinase, phosphoinositide 3-kinase, or AKT pathways .

The protein has a molecular weight of approximately 22 kDa, though it often appears at around 24 kDa in Western blots due to post-translational modifications . DIRAS2 is predominantly expressed in the brain, with marked expression in the prefrontal cortex, anterior cingulate cortex, and amygdala, suggesting significant roles in neurobiological functions .

What experimental evidence supports DIRAS2's tumor suppressor function?

DIRAS2 has been identified as a tumor suppressor in multiple cancer types through various experimental approaches:

In Skin Cutaneous Melanoma (SKCM):

• In vitro experiments demonstrated that SKCM tumor cell proliferation, migration, invasion, and metastasis were enhanced after DIRAS2 knockdown

• DIRAS2 depletion promoted melanoma growth and metastasis in vivo

• Mechanistically, silencing DIRAS2 activated the Wnt/β-catenin signaling pathway

In Colorectal Cancer (CRC):

• DIRAS2 expression was found to be downregulated in CRC and correlated with poor prognosis

• Functionally, DIRAS2 inhibited CRC cell proliferation and affected cell-cycle protein expression

• Mechanistically, DIRAS2 blocked NF-κB signaling pathways, inducing G0/G1 arrest

These findings collectively demonstrate DIRAS2's role as a tumor suppressor through multiple cell signaling pathways.

What are the recommended applications and dilutions for DIRAS2 antibodies?

Based on extensive validation studies, DIRAS2 antibodies have been optimized for multiple applications with specific dilution ranges:

It is important to note that these are starting recommendations, and the optimal dilution should be determined empirically for each specific application and experimental system . Sample-dependent variation may occur, so checking validation data for similar samples is advisable.

How should DIRAS2 antibodies be validated for experimental use?

A rigorous validation strategy for DIRAS2 antibodies should include multiple complementary approaches:

• Positive and Negative Controls:

  • Use tissues with known expression patterns (positive controls: human, mouse, and rat brain tissues )

  • Include negative controls such as non-transfected cell lines or tissues with minimal DIRAS2 expression

• Overexpression and Knockdown Validation:

  • Compare results between DIRAS2-transfected cells and controls

  • Validate antibody specificity using DIRAS2 knockdown or knockout models

• Blocking Peptide Competition:

  • Pre-incubate the antibody with the specific blocking peptide corresponding to the immunogen

  • Specific signals should be significantly reduced or eliminated in blocking experiments

• Multiple Antibody Comparison:

  • Use antibodies targeting different epitopes of DIRAS2 (e.g., C-terminal vs. full-length )

  • Consistent results across antibodies increase confidence in specificity

Example validation data from literature shows DIRAS2 detection in transfected 293T cells but not in non-transfected controls, confirming antibody specificity .

How does DIRAS2 expression influence tumor immune microenvironment?

DIRAS2 expression significantly impacts immune cell infiltration in tumors, particularly in skin cutaneous melanoma:

• DIRAS2 expression levels positively correlate with infiltration of:

  • B cells (r = 0.184, P = 9.05e-05)

  • CD4+ T cells (r = 0.123, P = 9.56e-03)

  • CD8+ T cells (r = 0.267, P = 1.44e-08)

• Higher immune cell infiltration in the DIRAS2 high expression group compared to the low expression group (P < 0.0001)

• The infiltration of B cells, CD4+ T cells, and CD8+ T cells positively correlates with improved patient survival rates in SKCM

These findings were established using advanced computational approaches including TIMER (Tumor Immune Estimation Resource) and CIBERSORT analyses of RNA-Seq data from 461 SKCM patients' tumor tissue samples from the TCGA database .

What is the evidence linking DIRAS2 to ADHD and neuropsychiatric traits?

Multiple genetic studies have established associations between DIRAS2 variants and attention deficit/hyperactivity disorder (ADHD):

• Linkage analyses implicated chromosome 9q22 (containing DIRAS2) in ADHD

• Association studies with 600 adult ADHD patients and 420 controls identified four SNPs and two haplotype blocks in DIRAS2 associated with ADHD (p=0.006-0.05)

• Meta-analysis showed a significant common odds ratio of 1.12 (p=0.04) for rs1412005 and confirmed association with a promoter risk haplotype (OR=1.45, p=0.0003)

• Replication in families with childhood ADHD confirmed the promoter haplotype block association (p=0.02)

Additionally, DIRAS2 variants have been associated with personality traits relevant to ADHD:

The brain-specific expression pattern of DIRAS2 in regions associated with executive function supports its role in ADHD pathophysiology .

How does DIRAS2 contribute to radiation resistance mechanisms in cancer cells?

DIRAS2 has been shown to promote radiation resistance in renal cell carcinoma through a specific mechanism involving autophagy:

• DIRAS2 expression is upregulated in human RCC tissues

• Overexpression of DIRAS2 promotes radiation resistance in RCC cell lines based on clonogenic survival assays

• DIRAS2 overexpression enhances radiation-induced autophagy levels

• Mechanistically, DIRAS2 upregulates the MKK4-JNK1-Bcl-2 pathway in response to ionizing radiation

Importantly, inhibition of autophagy using chloroquine (CQ) pre-treatment largely eliminated the effect of DIRAS2 overexpression on radiation resistance , suggesting a potential therapeutic strategy for overcoming radiation resistance in DIRAS2-expressing tumors.

What are the critical differences between monoclonal and polyclonal DIRAS2 antibodies?

When selecting between monoclonal and polyclonal DIRAS2 antibodies, researchers should consider these key differences:

Monoclonal DIRAS2 Antibodies:

• Generated from specific clones (e.g., OTI8A5 , OTI10H1 )

• Immunogens typically include recombinant protein fragments (e.g., amino acids 1-196 of human DIRAS2)

• Provide consistent specificity to a single epitope

• Show excellent performance in IHC applications across various human tissues

• Particularly useful for applications requiring high reproducibility

Polyclonal DIRAS2 Antibodies:

• Generated in hosts such as rabbits against synthetic peptides or full-length proteins

• Recognize multiple epitopes on DIRAS2, potentially offering increased sensitivity

• Typically validated across a broader range of applications (WB, ELISA, IF/ICC, IP, FC)

• May show greater lot-to-lot variation

• Often preferred for applications requiring maximum sensitivity

The optimal choice depends on specific experimental requirements and applications, with monoclonal antibodies generally preferred for consistency and polyclonal antibodies for sensitivity.

How can researchers study DIRAS2 protein-protein interactions?

To investigate DIRAS2 protein interactions, researchers can employ several methodological approaches:

• Co-Immunoprecipitation (Co-IP):

  • Use validated DIRAS2 antibodies for immunoprecipitation (recommended amount: 0.5-4.0 μg for 1.0-3.0 mg of total protein lysate)

  • Identify interaction partners by Western blot or mass spectrometry

  • Example: DIRAS2 has been shown to interact with 26S proteasome non-ATPase regulatory subunit 2 (PSMD2), which facilitates DIRAS2 degradation in a proteasome-mediated manner

• Proximity Ligation Assay (PLA):

  • Utilize specific DIRAS2 antibodies along with antibodies against potential interaction partners

  • This technique allows visualization of protein interactions in situ with high sensitivity

• Pull-down Assays:

  • Express tagged DIRAS2 (e.g., FLAG-tagged) for pull-down experiments

  • Verification can be performed using both anti-tag and anti-DIRAS2 antibodies

• Yeast Two-Hybrid Screening:

  • Use DIRAS2 as bait to identify novel interaction partners

  • Validate interactions using the methods above

Research has identified interactions between DIRAS2 and components of various signaling pathways, including the Wnt/β-catenin pathway and NF-κB pathway , providing insights into its tumor suppressor functions.

Why might Western blots with DIRAS2 antibodies show unexpected band patterns?

When troubleshooting unexpected band patterns in DIRAS2 Western blots, consider these methodological approaches:

• Multiple Bands:

  • DIRAS2 has a predicted molecular weight of 22 kDa, but observed bands may appear at 24 kDa due to post-translational modifications

  • Additional bands may represent:

    • Different isoforms or splice variants

    • Post-translational modifications (phosphorylation, ubiquitination)

    • Degradation products

    • Non-specific binding

• No Band or Weak Signal:

  • Increase antibody concentration (try 1:500 dilution for weak signals)

  • Optimize protein loading (25-35μg recommended based on validation studies)

  • Verify expression in your sample (DIRAS2 is highly expressed in brain tissue)

  • Consider longer exposure times

  • Ensure appropriate blocking and washing protocols

• High Background:

  • Use freshly prepared buffers

  • Increase washing duration/frequency

  • Reduce antibody concentration

  • Optimize blocking conditions (5% non-fat milk or BSA)

  • Consider more stringent washing conditions

• Validation Controls:

  • Include positive controls (brain tissue lysates or DIRAS2-transfected cells)

  • Use blocking peptides to confirm specificity

  • Compare results with different DIRAS2 antibodies

Example from published research: Western blot validation showed a specific 22 kDa band in DIRAS2-transfected 293T cells but not in non-transfected controls, confirming antibody specificity .

How can researchers optimize immunohistochemistry protocols for DIRAS2 detection?

For successful DIRAS2 immunohistochemical staining, consider these methodological refinements:

• Antigen Retrieval Optimization:

  • Heat-induced epitope retrieval using 1mM EDTA in 10mM Tris buffer (pH 8.5) at 120°C for 3 minutes has been validated for DIRAS2 detection

  • Compare with citrate buffer (pH 6.0) to determine optimal conditions for your specific tissue

• Antibody Selection and Dilution:

  • For paraffin-embedded tissues, monoclonal antibodies (e.g., clone OTI8A5) at 1:150 dilution have shown excellent results

  • Optimization may be required for different tissue types

• Positive and Negative Controls:

  • Include tissues with known DIRAS2 expression (human ovary, pancreas, thyroid, endometrium, prostate)

  • Use liver tissue as potential negative control

  • Include antibody diluent-only controls

• Detection System Optimization:

  • Use highly sensitive detection systems for low-abundance proteins

  • Consider signal amplification methods if needed

  • Optimize DAB development time

• Troubleshooting Specific Issues:

  • For weak staining: increase antibody concentration, extend incubation time, or enhance detection system

  • For high background: increase blocking time, add additional washing steps, reduce antibody concentration

  • For non-specific staining: validate antibody specificity with blocking peptides

Validated DIRAS2 immunohistochemistry has been performed across multiple tissue types with distinctive patterns, including in thyroid carcinoma and prostate carcinoma compared to their normal tissue counterparts .

Frequently Asked Questions (FAQs) for DIRAS2 Antibody Research

DIRAS2 (DIRAS Family, GTP-Binding RAS-Like 2) is a small GTPase protein with emerging significance in cancer research, neurodevelopmental disorders, and cellular signaling pathways. This comprehensive FAQ collection addresses key questions researchers encounter when working with DIRAS2 antibodies, focusing on methodological approaches and technical considerations based on current scientific literature.

What is DIRAS2 and what are its key molecular characteristics?

DIRAS2 belongs to a distinct branch of the Ras superfamily of monomeric GTPases. Unlike other Ras family proteins, DIRAS2 displays low GTPase activity and exists predominantly in the GTP-bound form . It has unique biochemical properties compared to other Ras kinases, as it fails to activate the MAP kinase, phosphoinositide 3-kinase, or AKT pathways .

The protein has a molecular weight of approximately 22 kDa, though it often appears at around 24 kDa in Western blots due to post-translational modifications . DIRAS2 is predominantly expressed in the brain, with marked expression in the prefrontal cortex, anterior cingulate cortex, and amygdala, suggesting significant roles in neurobiological functions .

What experimental evidence supports DIRAS2's tumor suppressor function?

DIRAS2 has been identified as a tumor suppressor in multiple cancer types through various experimental approaches:

In Skin Cutaneous Melanoma (SKCM):

• In vitro experiments demonstrated that SKCM tumor cell proliferation, migration, invasion, and metastasis were enhanced after DIRAS2 knockdown

• DIRAS2 depletion promoted melanoma growth and metastasis in vivo

• Mechanistically, silencing DIRAS2 activated the Wnt/β-catenin signaling pathway

In Colorectal Cancer (CRC):

• DIRAS2 expression was found to be downregulated in CRC and correlated with poor prognosis

• Functionally, DIRAS2 inhibited CRC cell proliferation and affected cell-cycle protein expression

• Mechanistically, DIRAS2 blocked NF-κB signaling pathways, inducing G0/G1 arrest

These findings collectively demonstrate DIRAS2's role as a tumor suppressor through multiple cell signaling pathways.

What are the recommended applications and dilutions for DIRAS2 antibodies?

Based on extensive validation studies, DIRAS2 antibodies have been optimized for multiple applications with specific dilution ranges:

It is important to note that these are starting recommendations, and the optimal dilution should be determined empirically for each specific application and experimental system . Sample-dependent variation may occur, so checking validation data for similar samples is advisable.

How should DIRAS2 antibodies be validated for experimental use?

A rigorous validation strategy for DIRAS2 antibodies should include multiple complementary approaches:

• Positive and Negative Controls:

  • Use tissues with known expression patterns (positive controls: human, mouse, and rat brain tissues )

  • Include negative controls such as non-transfected cell lines or tissues with minimal DIRAS2 expression

• Overexpression and Knockdown Validation:

  • Compare results between DIRAS2-transfected cells and controls

  • Validate antibody specificity using DIRAS2 knockdown or knockout models

• Blocking Peptide Competition:

  • Pre-incubate the antibody with the specific blocking peptide corresponding to the immunogen

  • Specific signals should be significantly reduced or eliminated in blocking experiments

• Multiple Antibody Comparison:

  • Use antibodies targeting different epitopes of DIRAS2 (e.g., C-terminal vs. full-length )

  • Consistent results across antibodies increase confidence in specificity

Example validation data from literature shows DIRAS2 detection in transfected 293T cells but not in non-transfected controls, confirming antibody specificity .

How does DIRAS2 expression influence tumor immune microenvironment?

DIRAS2 expression significantly impacts immune cell infiltration in tumors, particularly in skin cutaneous melanoma:

• DIRAS2 expression levels positively correlate with infiltration of:

  • B cells (r = 0.184, P = 9.05e-05)

  • CD4+ T cells (r = 0.123, P = 9.56e-03)

  • CD8+ T cells (r = 0.267, P = 1.44e-08)

• Higher immune cell infiltration in the DIRAS2 high expression group compared to the low expression group (P < 0.0001)

• The infiltration of B cells, CD4+ T cells, and CD8+ T cells positively correlates with improved patient survival rates in SKCM

These findings were established using advanced computational approaches including TIMER (Tumor Immune Estimation Resource) and CIBERSORT analyses of RNA-Seq data from 461 SKCM patients' tumor tissue samples from the TCGA database .

What is the evidence linking DIRAS2 to ADHD and neuropsychiatric traits?

Multiple genetic studies have established associations between DIRAS2 variants and attention deficit/hyperactivity disorder (ADHD):

• Linkage analyses implicated chromosome 9q22 (containing DIRAS2) in ADHD

• Association studies with 600 adult ADHD patients and 420 controls identified four SNPs and two haplotype blocks in DIRAS2 associated with ADHD (p=0.006-0.05)

• Meta-analysis showed a significant common odds ratio of 1.12 (p=0.04) for rs1412005 and confirmed association with a promoter risk haplotype (OR=1.45, p=0.0003)

• Replication in families with childhood ADHD confirmed the promoter haplotype block association (p=0.02)

Additionally, DIRAS2 variants have been associated with personality traits relevant to ADHD:

The brain-specific expression pattern of DIRAS2 in regions associated with executive function supports its role in ADHD pathophysiology .

How does DIRAS2 contribute to radiation resistance mechanisms in cancer cells?

DIRAS2 has been shown to promote radiation resistance in renal cell carcinoma through a specific mechanism involving autophagy:

• DIRAS2 expression is upregulated in human RCC tissues

• Overexpression of DIRAS2 promotes radiation resistance in RCC cell lines based on clonogenic survival assays

• DIRAS2 overexpression enhances radiation-induced autophagy levels

• Mechanistically, DIRAS2 upregulates the MKK4-JNK1-Bcl-2 pathway in response to ionizing radiation

Importantly, inhibition of autophagy using chloroquine (CQ) pre-treatment largely eliminated the effect of DIRAS2 overexpression on radiation resistance , suggesting a potential therapeutic strategy for overcoming radiation resistance in DIRAS2-expressing tumors.

What are the critical differences between monoclonal and polyclonal DIRAS2 antibodies?

When selecting between monoclonal and polyclonal DIRAS2 antibodies, researchers should consider these key differences:

Monoclonal DIRAS2 Antibodies:

• Generated from specific clones (e.g., OTI8A5 , OTI10H1 )

• Immunogens typically include recombinant protein fragments (e.g., amino acids 1-196 of human DIRAS2)

• Provide consistent specificity to a single epitope

• Show excellent performance in IHC applications across various human tissues

• Particularly useful for applications requiring high reproducibility

Polyclonal DIRAS2 Antibodies:

• Generated in hosts such as rabbits against synthetic peptides or full-length proteins

• Recognize multiple epitopes on DIRAS2, potentially offering increased sensitivity

• Typically validated across a broader range of applications (WB, ELISA, IF/ICC, IP, FC)

• May show greater lot-to-lot variation

• Often preferred for applications requiring maximum sensitivity

The optimal choice depends on specific experimental requirements and applications, with monoclonal antibodies generally preferred for consistency and polyclonal antibodies for sensitivity.

How can researchers study DIRAS2 protein-protein interactions?

To investigate DIRAS2 protein interactions, researchers can employ several methodological approaches:

• Co-Immunoprecipitation (Co-IP):

  • Use validated DIRAS2 antibodies for immunoprecipitation (recommended amount: 0.5-4.0 μg for 1.0-3.0 mg of total protein lysate)

  • Identify interaction partners by Western blot or mass spectrometry

  • Example: DIRAS2 has been shown to interact with 26S proteasome non-ATPase regulatory subunit 2 (PSMD2), which facilitates DIRAS2 degradation in a proteasome-mediated manner

• Proximity Ligation Assay (PLA):

  • Utilize specific DIRAS2 antibodies along with antibodies against potential interaction partners

  • This technique allows visualization of protein interactions in situ with high sensitivity

• Pull-down Assays:

  • Express tagged DIRAS2 (e.g., FLAG-tagged) for pull-down experiments

  • Verification can be performed using both anti-tag and anti-DIRAS2 antibodies

• Yeast Two-Hybrid Screening:

  • Use DIRAS2 as bait to identify novel interaction partners

  • Validate interactions using the methods above

Research has identified interactions between DIRAS2 and components of various signaling pathways, including the Wnt/β-catenin pathway and NF-κB pathway , providing insights into its tumor suppressor functions.

Why might Western blots with DIRAS2 antibodies show unexpected band patterns?

When troubleshooting unexpected band patterns in DIRAS2 Western blots, consider these methodological approaches:

• Multiple Bands:

  • DIRAS2 has a predicted molecular weight of 22 kDa, but observed bands may appear at 24 kDa due to post-translational modifications

  • Additional bands may represent:

    • Different isoforms or splice variants

    • Post-translational modifications (phosphorylation, ubiquitination)

    • Degradation products

    • Non-specific binding

• No Band or Weak Signal:

  • Increase antibody concentration (try 1:500 dilution for weak signals)

  • Optimize protein loading (25-35μg recommended based on validation studies)

  • Verify expression in your sample (DIRAS2 is highly expressed in brain tissue)

  • Consider longer exposure times

  • Ensure appropriate blocking and washing protocols

• High Background:

  • Use freshly prepared buffers

  • Increase washing duration/frequency

  • Reduce antibody concentration

  • Optimize blocking conditions (5% non-fat milk or BSA)

  • Consider more stringent washing conditions

• Validation Controls:

  • Include positive controls (brain tissue lysates or DIRAS2-transfected cells)

  • Use blocking peptides to confirm specificity

  • Compare results with different DIRAS2 antibodies

Example from published research: Western blot validation showed a specific 22 kDa band in DIRAS2-transfected 293T cells but not in non-transfected controls, confirming antibody specificity .

How can researchers optimize immunohistochemistry protocols for DIRAS2 detection?

For successful DIRAS2 immunohistochemical staining, consider these methodological refinements:

• Antigen Retrieval Optimization:

  • Heat-induced epitope retrieval using 1mM EDTA in 10mM Tris buffer (pH 8.5) at 120°C for 3 minutes has been validated for DIRAS2 detection

  • Compare with citrate buffer (pH 6.0) to determine optimal conditions for your specific tissue

• Antibody Selection and Dilution:

  • For paraffin-embedded tissues, monoclonal antibodies (e.g., clone OTI8A5) at 1:150 dilution have shown excellent results

  • Optimization may be required for different tissue types

• Positive and Negative Controls:

  • Include tissues with known DIRAS2 expression (human ovary, pancreas, thyroid, endometrium, prostate)

  • Use liver tissue as potential negative control

  • Include antibody diluent-only controls

• Detection System Optimization:

  • Use highly sensitive detection systems for low-abundance proteins

  • Consider signal amplification methods if needed

  • Optimize DAB development time

• Troubleshooting Specific Issues:

  • For weak staining: increase antibody concentration, extend incubation time, or enhance detection system

  • For high background: increase blocking time, add additional washing steps, reduce antibody concentration

  • For non-specific staining: validate antibody specificity with blocking peptides