cpt2 Antibody

What is CPT2 and why is it significant in metabolic research?

Carnitine palmitoyltransferase 2 (CPT2) is a critical enzyme (approximately 73.8 kDa) involved in the intramitochondrial synthesis of acylcarnitines from accumulated acyl-CoA metabolites. CPT2 reconverts acylcarnitines back into their respective acyl-CoA esters, enabling beta-oxidation—an essential step for mitochondrial uptake of long-chain fatty acids . The enzyme is particularly active with medium (C8-C12) and long-chain (C14-C18) acyl-CoA esters . CPT2 deficiency represents a form of long-chain fatty acid oxidation disorder (LCFAOD) with significant clinical implications . Recent research has also revealed CPT2's involvement in immune function regulation and potential roles in cancer progression , making it a valuable target for metabolic, immunological, and oncological investigations.

What experimental techniques can CPT2 antibodies be reliably used for?

CPT2 antibodies have been validated across multiple experimental platforms with specific methodological parameters:

All applications should include appropriate positive controls such as HEK-293T cells, T-47D cells, LNCaP cells, mouse/rat liver tissue, or MCF-7 cells, which consistently express detectable levels of CPT2 .

How should researchers validate CPT2 antibody specificity for experimental reliability?

A multi-tiered validation approach is essential to ensure CPT2 antibody specificity:

• Genetic validation: Use CPT2 knockout/knockdown models as negative controls. Research shows Cd2 iCre Cpt2 fl/fl mouse models with efficient CPT2 deletion in lymphocytes provide excellent specificity controls .

• Epitope-specific validation: Confirm recognition of the intended target sequence. Commercial antibodies typically use specific peptide sequences (e.g., "DTITFKRLIRFVPSSLSWYGAYLVNAYPLDMSQYFRLFNSTRLPKPSRDELFTDDKARHLLVLRKGNFYIFDVLDQDGNIVSPSE" or "MMVECSKYHGQLTKEAAMGQGFDRHLFALRHLAAAKGIILPELYLDPAYGQINHNVLSTSTLSSPAVNLGGFAPVVSDGFGVGYAVHDNWIGCNVSSYP") .

• Multi-technique confirmation: Validate expression using orthogonal methods (e.g., RNAseq validation parallel to antibody detection) .

• Cross-reactivity assessment: Test against protein arrays (commercial antibodies are typically tested against 364 human recombinant protein fragments) .

• Tissue panel assessment: Confirm expected tissue expression patterns across multiple tissues (e.g., 44 normal human tissues and 20 cancer tissue types) .

What are the optimal storage and handling conditions for maintaining CPT2 antibody efficacy?

To maintain optimal CPT2 antibody performance:

• Storage temperature: Store at -20°C; most commercial preparations are stable for one year after shipment .

• Buffer composition: Typically supplied in PBS with 0.02% sodium azide and 50% glycerol at pH 7.3 .

• Aliquoting considerations: For most commercial preparations, aliquoting is unnecessary for -20°C storage .

• Shipping conditions: Always transport on wet ice to maintain stability .

• Working dilutions: Prepare fresh working dilutions on the day of the experiment to ensure consistent binding efficiency.

• Contamination prevention: Use sterile techniques and avoid repeated freeze-thaw cycles which can lead to protein denaturation and reduced antibody performance.

How can researchers accurately measure CPT2 enzyme activity in biological samples?

CPT2 enzyme activity can be quantitatively assessed through several validated approaches:

• Lymphocyte-based assay: A fast method measuring CPT2 enzyme activity in human lymphocytes with detection of reaction products has been implemented and validated in clinical settings. This method effectively differentiated between:

  • CPT2 patients (homozygous for c.338T>C mutation) showing residual enzymatic activity

  • Heterozygous carriers displaying residual activity in the range of 42-75%

  • Healthy controls with normal activity levels

• ^13C isotope tracing: Stable isotope tracing reveals fatty acid-derived citrate production, which is highly reduced in CPT2-deficient cells, providing a quantitative measure of pathway activity .

• Acylcarnitine profile analysis: The ratio (C16+C18:1)/C2 has been identified as a more sensitive marker for CPT2 deficiency than individual acylcarnitine levels alone .

• Genetic correlation: Next-generation sequencing to identify CPT2 mutations (such as c.1711C>A; Pro571Thr) can complement enzyme activity measurements for comprehensive assessment .

How can researchers differentiate between CPT1 and CPT2 in experimental designs?

Despite sequence similarities between CPT1 and CPT2, several approaches enable specific detection and functional discrimination:

• Epitope targeting: Select antibodies raised against unique regions with minimal homology. For CPT2, targeting the mitochondrial matrix-facing domain provides specificity versus the outer mitochondrial membrane-localized CPT1 .

• Subcellular localization analysis: Use confocal microscopy with appropriate mitochondrial markers to distinguish CPT2 (mitochondrial matrix) from CPT1 (outer mitochondrial membrane):

  • CPT2 shows primarily mitochondrial matrix localization with some nuclear signal

  • CPT1 isoforms (CPT1A, CPT1B, CPT1C) display strict outer mitochondrial membrane localization

• Differential inhibition assays: Employ malonyl-CoA, which inhibits CPT1 but not CPT2, to discriminate their activities in functional studies.

• Isoform-specific primers: For gene expression studies, design primers targeting unique regions of CPT2 versus CPT1 isoforms. Quantitative real-time PCR can confirm specific targeting as demonstrated in studies of Cd2 iCre Cpt2 fl/fl mice .

• Molecular weight discrimination: In Western blot analysis, CPT2 typically appears at 65-70 kDa, while CPT1 isoforms range from 82-88 kDa, allowing discrimination by molecular weight .

What experimental design considerations are important when studying CPT2 in different tissue and cell types?

Tissue and cell-specific considerations for CPT2 studies include:

• Baseline expression reference: CPT2 expression varies significantly between tissues. The Human Protein Atlas database provides comprehensive baseline expression data across 64 cell lines, 48 human normal tissues, and 20 tumor tissues .

• Normal vs. tumor tissue expression: CPT2 is "strongly marked in normal tissues" compared to tumor tissues, necessitating appropriate controls when studying cancer models .

• Species-specific reactivity: Most commercially available antibodies show reactivity with human, mouse, and rat samples. When studying other species, cross-reactivity should be validated empirically .

• Immune cell considerations: For studies in lymphocytes or immune cells, note that while CPT2 is "required for optimal LCFA beta-oxidation in B cells," it appears "dispensable for B cell activation in vitro and humoral immunity in vivo" .

• Tissue-specific fixation protocols: For immunohistochemistry, optimize fixation based on tissue type:

  • Formalin-fixed paraffin-embedded tissues: Use antigen retrieval with TE buffer pH 9.0 or citrate buffer pH 6.0

  • Cell cultures: 4% paraformaldehyde fixation for 20 minutes followed by 0.1% Triton X-100 permeabilization for 15 minutes

What are the established methodologies for investigating CPT2 mutations and their functional impacts?

A comprehensive experimental pipeline for CPT2 mutation analysis includes:

• Mutation identification:

  • Whole-exome sequencing for novel mutation discovery

  • Sanger sequencing for confirmation and family screening

  • In silico analysis using multiple prediction programs (SIFT, Polyphen-2, CADD, MutationTaster) to assess pathogenicity

• Conservation analysis: Comparative alignment across species to determine evolutionary conservation of the affected residue, as demonstrated for the R631 residue in CPT2 .

• Protein localization studies:

  • Construct vectors expressing wild-type and mutant CPT2 fused to fluorescent tags (e.g., GFP, RFP)

  • Transfect into appropriate cell lines (e.g., HEK293)

  • Analyze subcellular localization using confocal microscopy

  • Quantify fluorescence signal intensity to assess potential protein degradation

• Protein-protein interaction analysis:

  • Create tagged expression constructs (e.g., His-tagged CPT2, FLAG-tagged interaction partners)

  • Perform co-immunoprecipitation assays with appropriate antibodies

  • Analyze interactions by Western blotting

  • Compare wild-type and mutant CPT2 interaction capabilities

• Enzymatic activity assays:

  • Measure CPT2 activity in lymphocytes or other relevant cell types

  • Compare activity levels between wild-type, heterozygous, and homozygous mutant samples

How does CPT2 interact with UCP2 and what experimental approaches best capture this interaction?

The CPT2-UCP2 interaction has significant implications for metabolic regulation and disease processes. Research has established robust protocols for studying this interaction:

• Co-immunoprecipitation protocol:

  • Construct expression vectors with appropriate tags (His-tagged CPT2 and FLAG-tagged UCP2)

  • Transfect HEK293 cells with these constructs individually or in combination

  • Harvest cells 24 hours post-transfection

  • Lyse in buffer containing 20 mM HEPES (pH 7.4), 100 mM KCl, 2 mM MgCl₂, 1 mM PMSF, 1% Triton X-100, and protease inhibitors

  • Incubate lysates with antibody-conjugated magnetic beads overnight at 4°C with continuous rotation

  • Wash beads four times with lysis buffer

  • Elute bound proteins in SDS loading buffer and analyze by Western blot using appropriate antibodies

• Mutational impact assessment: Research has shown that the c.1891C>T (p.R631C) mutation in CPT2 disrupts its interaction with UCP2, demonstrating that genetic variants can significantly alter this protein-protein interaction .

• Functional correlation: The CPT2-UCP2 interaction has been associated with gout/hyperuricemia, suggesting this interaction has broad metabolic implications beyond fatty acid oxidation .

How can CPT2 antibodies be effectively employed in cancer research?

CPT2 plays critical roles in cancer metabolism and immune responses, making it valuable for oncology research:

How can researchers integrate CPT2 antibody detection with metabolomic analyses?

Combining CPT2 antibody-based detection with metabolomics creates a powerful approach for understanding fatty acid metabolism in various physiological and pathological contexts:

• Integrative experimental design:

  • Perform parallel analyses of CPT2 protein expression/localization and metabolite profiles

  • Correlate CPT2 levels detected by antibodies with specific metabolite concentrations

  • Determine how genetic or pharmacological modulation of CPT2 affects metabolic profiles

• ^13C isotope tracing methodology:

  • Use stable ^13C isotope labeled fatty acids as substrates

  • Track fatty acid-derived citrate production via mass spectrometry

  • Correlate with CPT2 protein levels detected by immunological methods

  • Studies show highly reduced fatty acid-derived citrate production in CPT2-deficient B cells

• Acylcarnitine profile correlation:

  • Measure acylcarnitine profiles (particularly C16, C18:1, and the (C16+C18:1)/C2 ratio)

  • Correlate with CPT2 protein expression levels determined by antibody-based methods

  • Note that normal C16 and C18:1 levels don't completely rule out CPT2 deficiency

• Mitochondrial function assessment:

  • Combine CPT2 immunofluorescence with mitochondrial functional assays (e.g., oxygen consumption rate, mitochondrial membrane potential)

  • Colocalize CPT2 with mitochondrial markers to assess relationship between CPT2 expression patterns and mitochondrial function

What advanced techniques enable studying CPT2's role in immune cell metabolism and function?

CPT2's role in immune cell metabolism can be investigated through sophisticated experimental approaches:

• Lymphocyte-specific CPT2 deletion models:

  • Use Cd2 iCre Cpt2 fl/fl mice with efficient CPT2 deletion in lymphocyte lineages

  • Verify deletion through quantitative Real-time PCR for Cpt2 (with Cpt1a and Cpt1b as controls)

  • Analyze B and T cell development through flow cytometry of:

    • CD4⁻CD8⁻ double negative (DN)

    • CD4⁺CD8⁺ double positive (DP)

    • CD4⁺ and CD8⁺ single positive (SP) cells

    • CD4⁺Foxp3⁺ regulatory T cells (Tregs)

• B cell-specific studies:

  • Generate bone marrow chimeric mice with B cell-specific ablation of Cpt2

  • Assess humoral immunity through:

    • Analysis of B cell activation markers

    • Measurement of germinal center formation

    • Quantification of antibody production following thymus-dependent or -independent antigen challenges

• Fatty acid oxidation assessment in immune cells:

  • Perform ^13C isotope tracing to measure fatty acid-derived citrate production

  • Compare CPT2-deficient and wild-type immune cells to determine the contribution of CPT2 to fatty acid oxidation

  • Correlate with functional readouts like antibody production

• Imaging techniques:

  • Use immunofluorescence with CPT2 antibodies to visualize CPT2 localization in immune cells

  • Employ confocal microscopy to assess colocalization with mitochondrial markers

  • Perform live-cell imaging to monitor CPT2 dynamics during immune cell activation

How can researchers investigate the relationship between CPT2 and genetic alterations in disease models?

Advanced genetic analyses of CPT2 in disease contexts require sophisticated methodological approaches:

• Comprehensive genetic alteration analysis pipeline:

  • Access the cBioPortal for Cancer Genomics (http://cbioportal.org) to analyze CPT2 genetic alterations

  • Determine frequency, mutation type, copy number alteration (CNA), and structural variants in various cancers

  • Obtain mutation site information and 3D protein structure through the "mutation" model

• Structure-function correlation:

  • Generate expression constructs for wild-type and mutant CPT2

  • Assess impacts on subcellular localization using confocal microscopy

  • Quantify fluorescence signal intensity to determine if mutations affect protein stability

  • Example finding: The p.R631C mutation doesn't affect subcellular localization but reduces fluorescence intensity, suggesting potential protein degradation

• Protein-protein interaction analysis:

  • Construct expression vectors with tagged wild-type and mutant CPT2

  • Perform co-immunoprecipitation with potential interaction partners

  • Investigate how mutations affect these interactions

  • Example finding: The c.1891C>T variant disrupts CPT2's ability to bind UCP2

• Functional genomics approaches:

  • Apply CRISPR-Cas9 genome editing to introduce or correct specific CPT2 mutations

  • Use RNA interference to study the effects of reduced CPT2 expression

  • Employ overexpression systems to investigate gain-of-function effects

What experimental designs best capture the contribution of CPT2 to mitochondrial bioenergetics?

To comprehensively assess CPT2's role in mitochondrial energy metabolism:

How can CPT2 antibodies be optimized for challenging research applications?

For technically demanding applications, specialized approaches can enhance CPT2 antibody performance:

• Signal amplification techniques:

  • Tyramide signal amplification (TSA) for low-abundance detection

  • Quantum dot conjugation for enhanced sensitivity and photostability

  • Proximity ligation assay (PLA) for detecting CPT2 interactions with high specificity

• Live-cell imaging optimization:

  • Generate cell lines expressing fluorescently-tagged CPT2

  • Validate with conventional CPT2 antibodies to ensure proper localization and function

  • Use for real-time monitoring of CPT2 dynamics during metabolic challenges

• Tissue clearing techniques:

  • Apply CLARITY, CUBIC, or other tissue clearing methods

  • Use with CPT2 antibodies for 3D visualization in thick tissue sections

  • Optimize antibody penetration with extended incubation and specialized buffers

• Single-cell applications:

  • Adapt CPT2 antibodies for single-cell Western blotting

  • Optimize for CyTOF (mass cytometry) using metal-conjugated antibodies

  • Develop protocols for imaging mass cytometry to visualize CPT2 in tissue context with multiple markers

• Multiplex imaging approaches:

  • Develop compatible antibody panels including CPT2 and related metabolic proteins

  • Use spectral unmixing to resolve overlapping fluorophores

  • Apply cyclic immunofluorescence for high-parameter imaging in tissues