SHANK2 Antibody

What is SHANK2 and what is its role in neuronal function?

SHANK2 (SH3 and multiple ankyrin repeat domains protein 2) is a postsynaptic scaffolding protein found in excitatory synapses of the central nervous system. It functions as an adapter protein in the postsynaptic density (PSD) that interconnects receptors of the postsynaptic membrane, including NMDA-type and metabotropic glutamate receptors, with the actin-based cytoskeleton . SHANK2 plays a critical role in the structural and functional organization of dendritic spines and synaptic junctions, enabling cell signaling by anchoring and connecting membrane-bound receptors to the cytoskeleton in neurons . Some SHANK2 isoforms are expressed during development, while others are predominantly found in mature tissue, indicating its importance throughout neuronal development and mature function .

What are the common applications for SHANK2 antibodies in research?

SHANK2 antibodies are utilized in multiple experimental applications across neuroscience research:

Research demonstrates specific SHANK2 localization to cell bodies and processes in Purkinje neurons of the human cerebellum, making these antibodies valuable for studying specialized neuronal populations .

What is the molecular weight of SHANK2 protein and how does this impact detection methods?

• SHANK2-E (ankyrin repeat-containing isoform): 220-240 kDa

• CortBP1 (potential isoform): 165 kDa

When conducting Western blot analysis, researchers should anticipate bands at these molecular weights. The presence of multiple isoforms necessitates careful interpretation of results, particularly when studying tissue-specific or developmental expression patterns .

How do mutations in SHANK2 relate to neurological disorders, and how can antibodies help in investigating these mechanisms?

Mutations in the SHANK2 gene have been associated with autism spectrum disorders (ASD) and developmental delays . In a study using human induced pluripotent stem cells (hiPSCs) derived from a patient with a heterozygous deletion of SHANK2, researchers observed that SHANK2 mRNA and protein expression was reduced to approximately 50%, indicating haploinsufficiency .

When investigating SHANK2 mutations, researchers should consider:

• Using SHANK2 antibodies to quantify protein expression levels in patient-derived cells

• Examining co-localization with interacting proteins at the synapse

• Analyzing downstream signaling pathways affected by SHANK2 deficiency

Research has shown that SHANK2 mutations result in dysregulation of the ERK1/2 pathway, with decreased expression of mGluR5 and phospho-ERK1/2 confirmed in brain samples from Shank2(-/-) mice . These findings highlight the importance of excitatory-inhibitory balance and mGluR5 dysregulation with disturbed downstream ERK1/2 signaling in ASD, providing potential therapeutic targets .

What controls should be implemented when using SHANK2 antibodies for specificity validation?

Ensuring antibody specificity is critical for reliable SHANK2 research. Recommended controls include:

• Negative controls: Verify the absence of cross-reactivity with related proteins (SHANK1 and SHANK3). Many validated antibodies, such as EPR26549-331, are confirmed not to cross-react with human SHANK1 and SHANK3 .

• Positive controls: Use tissues known to express SHANK2, such as rat whole brain lysate, which should show bands at the expected molecular weight .

• Knockout/knockdown validation: Compare antibody staining between wild-type and Shank2(-/-) mouse tissue or siRNA-treated cells to confirm specificity.

• Multiple antibody approach: Use antibodies targeting different epitopes of SHANK2 to confirm observations.

• Recombinant protein control: Test antibody reactivity against recombinant SHANK2 protein fragments, such as those containing the SH3/PDZ domains (amino acids 84-309) .

How can researchers optimize SHANK2 detection in spinal cord tissue for pain-related studies?

Recent research has indicated that SHANK2 protein is involved in spinal NMDA receptor-mediated pain, with mutations potentially suppressing NMDA-ERK signaling in spinal pain transmission . When optimizing SHANK2 detection in spinal cord tissue:

• Tissue preparation: Use immersion fixation with appropriate fixatives to preserve protein epitopes.

• Blocking protocol: Incubate tissue with 5% normal rabbit serum and Fab anti-rabbit IgG (1:200) at room temperature for 20 minutes before applying the primary antibody .

• Primary antibody incubation: Incubate with anti-SHANK2 antibody overnight at room temperature for optimal binding .

• Secondary antibody selection: Use fluorophore-conjugated secondary antibodies such as Alexa488-conjugated donkey anti-rabbit IgG (1:400) for detecting SHANK2 protein .

• Co-localization studies: Consider dual immunostaining with markers for excitatory synapses to correlate SHANK2 expression with pain-related neural circuits.

What are the optimal storage conditions for maintaining SHANK2 antibody activity?

To maintain SHANK2 antibody activity and stability, follow these storage recommendations:

• For long-term storage: Aliquot and store at ≤ -20°C

• For short-term storage: Store at 2-8°C

• Avoid repeated freeze-thaw cycles to prevent protein degradation

• For reconstituted antibodies: Store at -20 to -70°C for up to 6 months under sterile conditions after reconstitution

• For improved recovery: Centrifuge vials prior to removing the cap

Storage buffers typically contain preservatives such as sodium azide in a neutral pH buffer (e.g., 10 mM Tris, 50 mM Sodium Chloride, 0.065% Sodium Azide, pH 7.18) to maintain antibody stability.

How should researchers optimize Western blotting protocols for SHANK2 detection?

For optimal detection of SHANK2 protein by Western blotting:

• Sample preparation:

  • Prepare lysates from tissues or cells expressing SHANK2

  • Include protease inhibitors to prevent degradation

• Gel electrophoresis:

  • Use lower percentage gels (6-8%) for better resolution of high molecular weight SHANK2 isoforms (160-240 kDa)

• Transfer conditions:

  • Extended transfer times or higher current settings may be necessary for complete transfer of large proteins

• Blocking and antibody incubation:

  • Follow manufacturer's recommended dilutions (typically 1:1000 for Western blotting)

  • Incubate primary antibody overnight at 4°C for improved signal-to-noise ratio

• Detection:

  • Use high-sensitivity detection methods for low-abundance SHANK2 isoforms

• Expected results:

  • Anticipate bands at approximately 165 kDa for the main SHANK2 isoform

  • Be aware of potential multiple bands corresponding to different isoforms (160-240 kDa)

What considerations are important when designing immunohistochemistry experiments with SHANK2 antibodies?

When planning immunohistochemistry experiments with SHANK2 antibodies:

• Fixation protocol:

  • Immersion fixation in paraformaldehyde is suitable for preserving SHANK2 epitopes

  • Paraffin-embedded sections of human brain (cerebellum) have been successfully used with SHANK2 antibodies

• Antibody concentration:

  • For IHC applications, a concentration of 3 µg/mL incubated overnight at 4°C has been effective

• Detection system:

  • HRP-DAB staining systems work well for visualizing SHANK2 in tissue sections

  • Counterstaining with hematoxylin provides good cellular context

• Expected localization:

  • SHANK2 staining should be localized to cell bodies and processes in Purkinje neurons when examining cerebellum

  • In spinal cord, examine SHANK2 expression in relation to NMDA receptors for pain-related studies

• Controls:

  • Include brain tissue from Shank2(-/-) mice as negative controls

  • Use sections from regions known to express high levels of SHANK2 as positive controls

How can SHANK2 antibodies be used to investigate synaptic dysfunction in neurological disorders?

SHANK2 antibodies provide valuable tools for studying synaptic abnormalities in various neurological conditions:

• Expression analysis:

  • Quantify SHANK2 levels in patient-derived samples using Western blot

  • Compare expression between affected individuals and controls

  • In patients with heterozygous SHANK2 deletions, protein expression is reduced to approximately 50%

• Morphological studies:

  • Examine dendritic spine morphology and maturation in relation to SHANK2 expression

  • Studies with patient-derived neurons showed a reduction in growth cone size and a transient increase in neuronal soma size during maturation

• Signaling pathway investigation:

  • Analyze SHANK2's interaction with the ERK-MAP kinase pathway components

  • Research shows SHANK2 mutations lead to decreased expression of mGluR5 and phospho-ERK1/2

• Excitatory-inhibitory balance:

  • Investigate SHANK2's role in maintaining proper excitatory-inhibitory signaling

  • Mature patient hiPSC-derived neurons showed dysregulated excitatory signaling

• Developmental studies:

  • Track SHANK2 expression during neuronal development

  • Research indicates SHANK2 deficiency affects neuronal proliferation (increased) and apoptosis (decreased) in both young and mature neurons

What are the technical challenges in detecting specific SHANK2 isoforms and how can they be addressed?

Detection of specific SHANK2 isoforms presents several challenges:

• Multiple isoform expression:

  • SHANK2 has several isoforms, including a 220-240 kDa ankyrin repeat-containing isoform (SHANK2-E) and a 165 kDa isoform (potentially CortBP1)

  • Some isoforms are developmentally regulated while others are expressed in mature tissue

• Epitope accessibility:

  • Different epitopes may be accessible in different isoforms

  • Select antibodies raised against conserved regions to detect multiple isoforms or against unique regions for isoform specificity

• Cross-reactivity concerns:

  • Ensure antibodies do not cross-react with SHANK1 or SHANK3 family members

  • Validated antibodies like N23B/6 have been tested for absence of cross-reactivity

• Solutions:

  • Use antibodies targeting different domains (SH3, PDZ, proline-rich regions)

  • Compare results with antibodies recognizing different epitopes

  • Consider using isoform-specific primers for RT-PCR validation

  • Employ recombinant protein standards representing different isoforms as controls

How should researchers design experiments to study SHANK2's interaction with glutamate receptors?

To investigate SHANK2's interactions with glutamate receptors:

• Co-immunoprecipitation approach:

  • Use SHANK2 antibodies at 1:50 dilution for immunoprecipitation experiments

  • Pull down SHANK2 and probe for associated glutamate receptors

  • Include appropriate controls (IgG control, input samples)

• Co-localization studies:

  • Perform double immunofluorescence staining for SHANK2 and glutamate receptors

  • Analyze co-localization in dendritic spines using confocal microscopy

  • Quantify co-localization using appropriate software and statistical analysis

• Proximity ligation assays:

  • Use this technique to detect close proximity of SHANK2 with glutamate receptors

  • Provides higher sensitivity than traditional co-localization studies

• Functional studies:

  • Examine the impact of SHANK2 knockdown on glutamate receptor localization and function

  • Measure changes in calcium signaling or electrophysiological properties

• Protein domain analysis:

  • Use antibodies targeting specific SHANK2 domains to determine which regions are crucial for glutamate receptor interactions

  • The PDZ domain of SHANK2 is particularly important for receptor interactions

By designing experiments with these considerations, researchers can gain valuable insights into the role of SHANK2 in excitatory synaptic function and its potential dysregulation in neurological disorders.