GPD2 Antibody

What is GPD2 and why is it significant in research?

GPD2 (Glycerol-3-phosphate dehydrogenase 2, mitochondrial) belongs to the FAD-dependent glycerol-3-phosphate dehydrogenase family. It localizes primarily to the inner mitochondrial membrane and catalyzes the conversion of glycerol-3-phosphate to dihydroxyacetone phosphate using FAD as a cofactor . GPD2, along with GPD1, constitutes the glycerol phosphate shuttle, which is essential for reoxidizing NADH formed during glycolysis . Recent research has revealed non-bioenergetic roles of mitochondrial GPD2 in cancer metabolism and tumor progression, making it an important target for oncology research .

What are the principal applications of GPD2 antibodies in research?

GPD2 antibodies have been validated for multiple research applications:

Different antibodies show varying levels of effectiveness across these applications, so researchers should select antibodies validated specifically for their intended application .

How do I select between monoclonal and polyclonal GPD2 antibodies?

The choice depends on your specific research needs:

Monoclonal GPD2 antibodies:

• Provide high specificity to a single epitope

• Ensure batch-to-batch consistency

• Optimal for quantitative analysis and flow cytometry

• Example: Mouse monoclonal antibody 68174-1-Ig shows high specificity in Western blotting with dilutions up to 1:50000

Polyclonal GPD2 antibodies:

• Recognize multiple epitopes, improving detection sensitivity

• Better for proteins with low expression levels

• Useful when protein conformation may be altered

• Example: Rabbit polyclonal 17219-1-AP can be used across WB, IHC, and IP applications

For experiments requiring precise epitope targeting, monoclonal antibodies like clone PSH0-31 (which targets human GPD2 aa 43-727) provide consistent results . For broader detection capabilities, especially in IHC, polyclonal antibodies may offer advantages.

What positive controls should be used when validating GPD2 antibodies?

Based on validated positive samples from multiple sources:

For Western Blotting:

• Cell lines: HeLa, LNCaP, HSC-T6, NIH/3T3, 4T1, A172, MCF-7, THP-1, U87-MG

• Tissue lysates: Mouse skeletal muscle, mouse liver tissue

For Immunoprecipitation:

• Mouse skeletal muscle tissue has been successfully used

For Immunohistochemistry:

• Mouse testis tissue (with recommended antigen retrieval using TE buffer pH 9.0)

• Human esophagus cancer tissue

When validating a new GPD2 antibody, these positive controls should demonstrate the expected band at approximately 68-81 kDa (observed molecular weight often differs from calculated 81 kDa) .

What explains the discrepancy between calculated and observed molecular weights for GPD2?

GPD2 antibodies frequently detect a protein at ~68 kDa despite the calculated molecular weight of 81 kDa . This discrepancy may result from:

• Post-translational modifications affecting protein migration

• Alternative splicing (two transcript variants of GPD2 have been identified)

• Proteolytic processing of the full-length protein

• Specific protein conformation affecting migration patterns

When validating Western blot results, researchers should note that the calculated molecular weight for GPD2 is 81 kDa, but the observed weight is typically around 68 kDa as confirmed by multiple antibody vendors . Some antibodies may also detect additional isoforms at 41 kDa .

What are the recommended antigen retrieval methods for GPD2 immunohistochemistry?

For optimal GPD2 detection in tissue sections:

• Primary recommendation: TE buffer pH 9.0

• Alternative method: Citrate buffer pH 6.0

The selection of antigen retrieval method can significantly impact staining results. For example, with the 17219-1-AP antibody, TE buffer pH 9.0 is specifically recommended, though citrate buffer pH 6.0 can serve as an alternative . Always optimize the antigen retrieval protocol for your specific tissue type and fixation method to maximize signal-to-noise ratio.

How do GPD2 antibodies contribute to understanding cancer metabolism?

Recent research has revealed critical roles of GPD2 in cancer biology beyond its conventional bioenergetic function:

• Tumor progression: Knockout (KO) of GPD2 resulted in suppression of cell growth and inhibition of tumor progression in vivo .

• Ether lipid metabolism: GPD2 provides dihydroxyacetone phosphate (DHAP) for ether lipid biosynthesis. GPD2 KO cells exhibited significantly lower ether lipid levels, and their slower growth was rescued by supplementation of DHAP precursor or ether lipids .

• Signaling pathway modulation: Mechanistically, ether lipid metabolism has been associated with the Akt pathway. Downregulation of the Akt/mTORC1 pathway due to GPD2 KO was rescued by DHAP supplementation .

Researchers can use GPD2 antibodies to:

• Validate knockout efficiency in GPD2 KO models

• Assess GPD2 expression levels across cancer types

• Investigate subcellular localization in different cancer cell lines

• Track changes in GPD2 expression following therapeutic interventions

How can CRISPR-Cas9 be used with GPD2 antibodies in creating knockout models?

CRISPR-Cas9 systems have been successfully employed to create GPD2 genetic knockout cell lines, with GPD2 antibodies serving as crucial validation tools:

Protocol Overview:

• Design guide RNA sequences targeting GPD2 (e.g., 5'-TCAGGTGAGCCTGGCATATGTGG-3' or 5'-GCACTAGATGCCGTCACCAGAGG-3')

• Transfect cells with CRISPR-Cas9 vector using Lipofectamine™ 3000

• Select transfected cells with puromycin (5 μg/mL for >72h)

• Isolate single-cell-derived clones

• Validate knockout using Western blot with anti-GPD2 antibodies

The complete absence of GPD2 protein expression in Western blot analysis using validated GPD2 antibodies confirms successful knockout . This approach has been effectively used in 4T1 cell lines to study GPD2's role in cancer progression.

What evidence supports GPD2's non-bioenergetic roles in cancer?

Multi-omics studies have revealed unexpected functions of GPD2 beyond energy metabolism:

• Metabolomic findings: GPD2 KO cells exhibited major changes in ether lipid metabolism, for which GPD2 provides DHAP in ether lipid biosynthesis .

• Rescue experiments: The slower growth of GPD2 KO cells was rescued by supplementation of a DHAP precursor or ether lipids, indicating a mechanistic link .

• Pathway analysis: Ether lipid metabolism was associated with the Akt pathway, and downregulation of Akt/mTORC1 pathway due to GPD2 KO was rescued by DHAP supplementation .

These findings were established through careful experimental design using GPD2 antibodies to confirm knockout status and overexpression. GPD2 antibodies are therefore essential tools for validating model systems when investigating these non-canonical functions.

How can Western blot results for GPD2 be optimized?

For optimal Western blot detection of GPD2:

Sample Preparation:

• Use appropriate lysis buffers that maintain protein integrity

• Include protease inhibitors to prevent degradation

• Consider extracting mitochondrial fractions for enriched GPD2 detection

Protocol Optimization:

• Use 10% SDS-PAGE gels for optimal separation

• Transfer proteins to PVDF membranes

• Block with 5% non-fat dry milk in TBST for 1 hour at room temperature

• Incubate with primary GPD2 antibody at recommended dilution (e.g., 1:1000 for NBP3-32402) in 5% NFDM/TBST at room temperature for 2 hours

• Use appropriate HRP-conjugated secondary antibody (e.g., Goat Anti-Rabbit IgG)

Controls:

• Include positive control lysates (HeLa, MCF-7, or mouse skeletal muscle)

• Use molecular weight markers to verify the 68 kDa observed band

Follow antibody-specific protocols, as some may require different conditions. For example, the Western blot protocol for GPD2 antibody 68174-1-Ig may have specific recommendations for optimal results .

Why might flow cytometry results with GPD2 antibodies be inconsistent?

Flow cytometry with GPD2 antibodies requires careful optimization due to several factors:

• Cell fixation and permeabilization: GPD2's mitochondrial localization requires adequate permeabilization for antibody access .

• Antibody concentration: Higher concentrations may be needed compared to Western blotting (e.g., 1 μg/ml for NBP3-32402) .

• Secondary antibody selection: Use fluorophore-conjugated secondary antibodies with minimal spectral overlap with other channels.

• Controls: Include appropriate isotype controls (e.g., Rabbit IgG Isotype Control when using rabbit anti-GPD2) and unlabelled samples.

A successful protocol example:

• Fix and permeabilize cells thoroughly

• Incubate with primary GPD2 antibody (1 μg/ml) at 4°C for 1 hour

• Wash cells thoroughly

• Incubate with fluorophore-conjugated secondary antibody (e.g., iFluor™ 488 conjugate-Goat anti-Rabbit IgG) at 1:1000 dilution for 30 minutes at 4°C

• Include both isotype and unlabelled controls

What strategies address non-specific binding in GPD2 immunohistochemistry?

To reduce non-specific binding in GPD2 immunohistochemistry:

• Optimize blocking conditions: Use species-appropriate serum or BSA (3-5%) for 1 hour at room temperature before antibody incubation.

• Antibody dilution optimization: Titrate antibodies to find the optimal concentration (e.g., 1:250-1:1000 for 17219-1-AP in IHC) .

• Antigen retrieval optimization: Use the recommended TE buffer pH 9.0 or citrate buffer pH 6.0 .

• Secondary antibody controls: Include controls without primary antibody to identify non-specific secondary antibody binding.

• Tissue-specific considerations: For certain tissues like testis, specific fixation and processing protocols may be necessary for optimal results .

How does GPD2 function in hepatocellular carcinoma progression?

Recent integrated analysis published in March 2025 identified GPD2 as a significant factor affecting hepatocellular carcinoma (HCC) prognosis:

• Correlation with progression: Upregulation of GPD2 expression was closely related to tumor progression in HCC .

• Prognostic value: GPD2 significantly affected the prognosis of HCC patients, with higher expression associated with poorer outcomes .

• Immune microenvironment: GPD2 expression was associated with changes in the immune microenvironment of HCC tumors .

These findings were established through integration of gene expression data from multiple datasets (GSE14520, GSE76427, and TCGA-LIHC) and validated using techniques including qPCR and immunohistochemistry with GPD2 antibodies . Further functional assays including wound-healing, Transwell, and Matrigel invasion assays demonstrated GPD2's role in cell migration, invasion, and apoptosis.

What are the implications of GPD2's role in ether lipid metabolism for cancer research?

The discovery of GPD2's involvement in ether lipid metabolism opens new research avenues:

• Metabolic reprogramming: GPD2 provides DHAP for ether lipid biosynthesis, affecting cancer cell metabolism beyond energy production .

• Signaling pathway modulation: Ether lipids influence the Akt/mTORC1 pathway, linking GPD2 to critical cancer signaling networks .

• Therapeutic targeting: The connection between GPD2, ether lipids, and cancer aggressiveness suggests potential for therapeutic intervention .

This represents a paradigm shift from viewing GPD2 solely as a component of the glycerol phosphate shuttle to recognizing its broader metabolic functions. GPD2 antibodies are essential tools for investigating these relationships, particularly for:

• Assessing GPD2 expression across cancer types

• Correlating GPD2 levels with ether lipid profiles

• Evaluating effects of GPD2 modulation on cancer cell phenotypes

How does GPD2 interact with the human complement system?

An unexpected role for GPD2 has been discovered in immune evasion:

GPD2 has been identified as a novel factor H-, factor H-like protein 1 (FHL-1)-, and plasminogen-binding surface protein in Candida albicans . This fungal protein:

• Binds to factor H and FHL-1, primarily via short consensus repeat 7

• Binds plasminogen via lysine residues

• When attached to Candida GPD2, these human complement regulators become functionally active

• Assists in inactivating the complement cascade

This research demonstrates an unexpected role for GPD2 in pathogen-host interactions, highlighting the importance of studying GPD2's roles beyond metabolism. While this study focused on fungal GPD2, it raises questions about potential similar interactions of human GPD2 with complement factors.

This research area represents an emerging field where GPD2 antibodies can be useful for:

• Investigating potential analogous functions of human GPD2

• Studying cross-reactivity between human and pathogen GPD2

• Exploring GPD2's potential roles in immune modulation