gpd1l Antibody

What is GPD1L and why is it important in research?

GPD1L is a 351 amino acid protein (38 kDa) encoded by the GPD1L gene located on chromosome 3p22.3. It catalyzes the conversion of sn-glycerol 3-phosphate to glycerone phosphate and shares 84% homology with glycerol-3-phosphate dehydrogenase 1 (GPD1) .

GPD1L has gained significant research interest due to its:

• Critical role in cardiac function through regulation of sodium channel trafficking

• Association with Brugada syndrome type 2 and sudden infant death syndrome

• Involvement in NAD+/NADH-dependent redox reactions

• Dysregulation in various cancers, particularly hepatocellular carcinoma

• Contribution to ferroptosis defense mechanisms

For researchers investigating these areas, GPD1L antibodies provide a vital tool for protein detection, localization, and functional studies.

What applications are GPD1L antibodies most commonly optimized for?

GPD1L antibodies have been validated for multiple research applications, though their performance varies by manufacturer and antibody type. Based on the available data:

When selecting an application, researchers should review the validation data provided by manufacturers for their specific antibody clone .

How do you validate GPD1L antibody specificity for your experimental system?

Antibody validation is critical for reliable research outcomes. For GPD1L antibodies, consider the following validation approaches:

• Positive controls: Use tissues/cells known to express GPD1L, such as:

  • Heart tissue (mouse, human)

  • Brain tissue (human)

  • Skeletal muscle tissue (human)

  • Cell lines: HEK-293, A549, HepG2, MDA-MB-231

• Negative controls:

  • Use GPD1L knockout/knockdown samples when available

  • Compare with non-specific antibodies of the same isotype

• Molecular weight verification:

  • Look for bands at 38-40 kDa (polyclonal)

  • Or 35-40 kDa (recombinant)

• Cross-reactivity assessment:

  • Test in multiple species if cross-reactivity is claimed (most GPD1L antibodies react with human, mouse, and rat samples)

• Advanced validation:

  • siRNA knockdown experiments (as demonstrated in Liu et al., 2017)

  • Immunoprecipitation followed by mass spectrometry

An example validation approach: "We validated our GPD1L antibody specificity by Western blot analysis in HEK-293 cells with and without GPD1L siRNA knockdown, confirming a reduction in the 38 kDa band intensity corresponding to GPD1L protein levels" .

What are the optimal Western blot protocols for GPD1L detection?

Based on published methodologies, the following protocol has been optimized for GPD1L detection :

Sample preparation:

• For tissue samples: Pulverize under liquid nitrogen and homogenize with a tissue homogenizer

• For total protein: Disrupt cells by sonication

• For membrane proteins: Centrifuge homogenate at 1000g (10 min, 4°C), spin supernatant at 100,000g (1 hr, 4°C), resuspend pellet in 1% SDS buffer

Electrophoresis and transfer:

• Load 10-30 μg protein per lane

• Use 4-15% gradient polyacrylamide gels

• Transfer to PVDF membrane (Immobilon-P)

Detection:

• Block with 5% nonfat dried milk in TBS

• Primary antibody incubation:

  • For polyclonal: 1:500-1:2000 dilution

  • For recombinant: 1:5000-1:50000 dilution

  • Incubate overnight at 4°C

• Wash with TBS containing 0.05% Tween 20

• Secondary antibody: alkaline phosphatase-conjugated goat anti-rabbit IgG (1:7500)

• Visualization with chemiluminescent substrate (e.g., CDP-Star)

This protocol has successfully detected GPD1L in cardiac tissue samples and multiple cell lines in published research .

How can GPD1L antibodies be used to investigate cardiac arrhythmias and Brugada syndrome?

GPD1L mutations have been directly linked to Brugada syndrome type 2 and cardiac arrhythmias. Researchers have used GPD1L antibodies to elucidate the underlying mechanisms:

• Mutation-specific studies:

  • The A280V mutation in GPD1L reduces SCN5A surface membrane expression and decreases inward Na+ current

  • GPD1L-A306del modifies sodium current in families carrying SCN5A-G1661R

• Methodological approaches:

  • Coexpression studies: Analyze GPD1L and SCN5A localization using fluorescently tagged proteins and antibodies in heterologous expression systems

  • Quantification of membrane expression: Compare wild-type vs. mutant GPD1L effects on sodium channel membrane expression using cell surface biotinylation followed by Western blotting

  • Functional analysis: Correlate GPD1L expression with electrophysiological parameters measured by patch-clamp techniques

• Research findings:

  • Wild-type GPD1L localizes near the cell surface to a greater extent than mutant forms

  • Coexpression of A280V GPD1L with SCN5A reduced SCN5A cell surface expression by 31±5% (p=0.01)

  • GPD1L mutations decrease cardiac Na+ current by approximately 50%

These approaches have revealed that GPD1L mutations can act as disease modifiers in patients with inherited arrhythmias, potentially explaining phenotypic variability .

What is the role of GPD1L in cancer and how can antibodies help investigate this connection?

Recent studies have revealed a complex relationship between GPD1L and cancer, with important implications for prognosis and treatment. GPD1L antibodies have been instrumental in these discoveries:

• Prognostic significance:

  • Analysis of hepatocellular carcinoma (HCC) showed that high GPD1L expression correlates with poor survival

  • GPD1L exhibits increased expression and promoter demethylation with advancing tumor stage

• Methodological applications:

  • Spatial and single-cell transcriptome analysis to confirm elevated GPD1L expression in tumor tissue compared to adjacent normal tissue

  • Western blot quantification of GPD1L expression across different HCC cell lines (e.g., PLC/PRF/5, HepG2, Hep3B)

  • siRNA knockdown experiments to assess GPD1L's functional role in drug sensitivity

• Therapeutic implications:

  • GPD1L expression in HCC cell lines shows robust inverse correlation with therapeutic response to several drugs

  • Lower GPD1L expression (in PLC/PRF/5 and HepG2) correlated with greater resistance to PF-562271, Linsitinib, and BMS-754807 compared to Hep3B cells with higher GPD1L expression

  • GPD1L knockdown in Hep3B cells reduced sensitivity specifically to PF-562271

• Research approach: "We selected three HCC cell lines with varying levels of GPD1L expression verified by Western blot. The cell lines with lower GPD1L expression exhibited greater resistance to all three drugs compared to the cell line with highest GPD1L expression, suggesting GPD1L as a potential biomarker for drug response" .

These findings highlight GPD1L's potential as a predictive biomarker for therapeutic response in cancer treatment, particularly for FAK inhibitors .

How does GPD1L function in the NADH shuttle system and how can antibodies help study this process?

GPD1L plays a role in the glycerol-3-phosphate (G3P) shuttle, which is crucial for maintaining the NAD+/NADH balance in cells. Antibodies against GPD1L can help elucidate this function:

• Biochemical mechanism:

  • GPD1L is involved in NAD+/NADH dependent reverse redox reaction of dihydroxyacetone phosphate to glycerol 3-phosphate

  • This process is critical for regenerating cytosolic NAD+ during high glycolytic flux

• Experimental approaches:

  • Measure the relative activity of GPD1/GPD1L using isotope tracing (M+2 G3P/(M+1 NADH × M+1 DHAP))

  • Assess the impact of GPD1L knockdown or overexpression on lactate production and NAD+ recycling

  • Combine with enzymatic assays to measure G3P levels and NAD+/NADH ratios

• Research findings:

  • GPD1L overexpression increases the rate of cytosolic NAD+ regeneration and decreases lactate excretion

  • Knockdown of GPD1L leads to increased lactate production but decreased cellular proliferation

  • Cells prefer to use MDH1 and GPD1/GPD1L to regenerate cytosolic NAD+ before engaging LDH activity

• Antibody applications:

  • Western blot analysis to confirm knockdown efficiency in siRNA experiments (typically using 1:1000 dilution of anti-GPD1L antibodies)

  • Immunofluorescence to examine subcellular localization in relation to mitochondria and other shuttle components

  • Immunoprecipitation to identify protein-protein interactions within the shuttle system

Understanding this system has important implications for cancer metabolism, as cancer cells may rely on these shuttles before engaging in aerobic glycolysis .

How can GPD1L antibodies be used to study ferroptosis defense mechanisms?

Recent research has identified a previously unrecognized role for GPD1L in ferroptosis defense mechanisms. Antibodies are crucial for investigating this connection:

• Current understanding:

  • GPD1L, along with GPD1, may have redundant functions in generating G3P, which is important for ferroptosis defense

  • Single knockout of GPD1 did not affect RSL3-induced ferroptosis, but double knockout of GPD1/GPD1L sensitized cells to ferroptosis

• Antibody applications:

  • Western blot analysis to confirm knockout efficiency in GPD1/GPD1L knockout cell lines

  • Immunoblotting to analyze protein expression in mitochondrial fractions versus whole cell lysates

  • Co-immunoprecipitation to identify interactions with other ferroptosis regulatory proteins

• Experimental methodology:

  • Generate GPD1L knockout cell lines using CRISPR-Cas9 and verify by Western blot

  • Extract mitochondrial protein using fractionation kits and analyze GPD1L expression

  • Use 30 μg of protein for immunoblot analysis with GPD1L antibody (1:1000, 17263-1-AP; Proteintech)

  • Include appropriate controls such as GPX4, DHODH, SLC7A11, ACSL4, and COQ2

• Research findings:

  • Expression analysis revealed that while GPD2 and GPD1L are relatively ubiquitous in different tissues and cancer cells, GPD1 expression is low in most cancer cell lines

  • GPD1 is mainly expressed in adipose and mammary tissues, suggesting GPD1L compensates for GPD1's function in generating G3P in many cancer cells

This research direction opens new possibilities for cancer therapy through modulation of the ferroptosis pathway involving GPD1L .

What are the challenges in detecting endogenous GPD1L in different experimental systems?

Researchers face several challenges when detecting endogenous GPD1L:

• Tissue-specific expression patterns:

  • GPD1L is abundantly expressed in heart tissue but shows variable expression in other tissues

  • Expression analysis revealed that GPD1L (but not GPD1) is relatively ubiquitous in different tissues and cancer cells

• Antibody selection considerations:

  • Choose antibodies raised against conserved epitopes, such as the peptide sequence QTSAEVYRILKQKGLLDK (amino acids 303-320 in human GPD1L)

  • Verify antibody specificity using positive control tissues (heart tissue is recommended)

• Protocol optimization by sample type:

  Sample Type	Recommended Protocol Modifications	Expected Results
  Heart tissue	Pulverize under liquid nitrogen; use 1:500-1:1000 dilution	Strong band at 38-40 kDa
  Brain tissue	Include protease inhibitors; may need longer exposure	Moderate band at 38-40 kDa
  Cancer cell lines	May require higher protein loading (30 μg); optimize antibody concentration	Variable expression levels
  Transfected cells	Use lower antibody dilution (1:2000-1:5000); include non-transfected control	Overexpression band at expected MW

• Subcellular localization challenges:

  • GPD1L may shuttle between cytosolic and membrane-associated locations

  • For membrane protein extraction, specialized fractionation protocols are required

  • Verify fractionation quality with compartment-specific markers when analyzing GPD1L distribution

• Documentation from published research: "Western blotting was performed using standard protocols. For membrane proteins, mouse or human hearts were pulverized under liquid nitrogen and homogenized. The homogenate was centrifuged at 1000g for 10 minutes at 4°C; the supernatant was spun at 100,000g for 1 hour at 4°C; and the pellet was resuspended in a buffer containing 1% SDS" .

These considerations help ensure reliable detection and characterization of endogenous GPD1L across different experimental systems.

How do mutations in GPD1L affect antibody binding and protein detection?

Mutations in GPD1L can potentially impact antibody binding and detection, which is important to consider when studying disease-associated variants:

• Common GPD1L mutations in research:

  • A280V: Associated with Brugada syndrome

  • E83K: Affects GPD1L function in sodium channel regulation

  • A306del: Modifies sodium current in families with cardiac arrhythmias

• Impact on antibody binding:

  • Epitope-dependent effects: Mutations within the epitope recognized by the antibody may directly reduce binding affinity

  • Conformational changes: Mutations distant from the epitope may still alter protein folding and accessibility

  • Post-translational modifications: Mutations may alter phosphorylation patterns or other modifications that affect antibody recognition

• Experimental considerations:

  • Use multiple antibodies targeting different epitopes when studying mutant proteins

  • Include wild-type GPD1L as a positive control in parallel experiments

  • Consider using epitope-tagged constructs (GFP-fused GPD1L) to trace trafficking of mutant proteins

  • For A280V mutation studies, researchers have successfully used GFP-fusion constructs with C-terminal tags to avoid interference with mutated regions

• Published approach: "GPD1L–GFP fusion constructs (GFP at the C terminus) were identified by DNA sequencing and Western blotting of cell lysates of transiently transfected COS-7 cells in which GFP-fused GPD1L ran as a slower band (≈70 kDa) compared with the GPD1L band (≈40 kDa)" .

Understanding these factors is essential when designing experiments to study mutant GPD1L proteins in disease models.

What cross-reactivity issues should researchers be aware of when using GPD1L antibodies?

When working with GPD1L antibodies, researchers should consider potential cross-reactivity with related proteins:

• Homologous proteins:

  • GPD1: Shares 84% homology with GPD1L

  • GPD2: Functions in the same metabolic pathway but is structurally distinct

• Species cross-reactivity:

  • Most commercial GPD1L antibodies show reactivity with human, mouse, and rat samples

  • When studying other species, validation is essential as epitope conservation may vary

• Testing and validation approaches:

  • Perform Western blot analysis with recombinant GPD1 and GPD1L proteins side by side

  • Include GPD1L knockout samples as negative controls when available

  • Consider pre-absorption controls with the immunizing peptide to confirm specificity

  • For novel applications or species, validate using siRNA knockdown approaches

• Documentation examples:

  • "The chosen peptide was highly conserved in human GPD1L, in which the corresponding sequence is QTSAEVYRILKQKGLLDK (accession number NM_015141)"

  • "The antibody was directed against the peptide sequence QTSAEVYRILRQKGLLDK corresponding to amino acids 303 through 320 in mouse GPD1L protein (accession number NP_780589)"

By considering these factors and implementing appropriate controls, researchers can minimize issues related to antibody cross-reactivity when studying GPD1L.

How can GPD1L antibodies be used to investigate protein-protein interactions?

GPD1L participates in several important protein-protein interactions, particularly with sodium channels. Antibodies can help characterize these interactions:

• Immunoprecipitation approaches:

  • Co-immunoprecipitation (Co-IP) using GPD1L antibodies can pull down interaction partners

  • Reverse Co-IP using antibodies against suspected interacting proteins can confirm interactions

  • For GPD1L-SCN5A interactions, researchers have successfully used rabbit anti-SCN5A antibodies (1:1000 dilution) from Alomone Labs

• Visualization of interactions:

  • Immunofluorescence colocalization studies using:

    • GPD1L antibodies (or GPD1L-GFP fusion proteins)

    • Antibodies against interacting proteins (e.g., SCN5A)

    • Subcellular markers (e.g., phalloidin Cy5 to delineate cortical actin)

  • Proximity ligation assays (PLA) to visualize interactions in situ

• Functional analysis of interactions:

  • Combine antibody approaches with electrophysiological measurements to correlate GPD1L-protein interactions with functional outcomes

  • Use mutant forms of GPD1L (e.g., A280V, E83K) to assess how mutations affect protein interactions

• Research findings:

  • Wild-type GPD1L localizes near the cell surface to a greater extent than A280V GPD1L

  • Coexpression of A280V GPD1L with SCN5A reduced SCN5A cell surface expression by 31±5% (p=0.01)

  • GPD1L mutations affect sodium channel trafficking through PKC-dependent phosphorylation

These techniques have been crucial in establishing GPD1L's role in cardiac sodium channel regulation and identifying the molecular mechanisms underlying Brugada syndrome .