PEX11-5 Antibody

What is the primary function of PEX11 proteins in cellular biology?

PEX11 proteins play a critical role in promoting peroxisome division in eukaryotic cells. Multiple studies have demonstrated that PEX11 proteins are unique in their ability to drive peroxisome division independent of peroxisomal metabolism. Research shows that overexpression of PEX11 causes a pronounced increase in peroxisome abundance, while deletion of PEX11 genes results in reduced peroxisome numbers . The division process mediated by PEX11 proteins proceeds through distinct kinetic phases, beginning with localization to peroxisomes, followed by elongation of peroxisomal structures, and culminating in increased peroxisome abundance . This division function is conserved across species, from yeasts to humans, making PEX11 antibodies valuable tools for studying peroxisome biogenesis across model organisms.

How does PEX11-5 differ from other PEX11 isoforms?

PEX11-5 represents one of multiple PEX11 isoforms found in plants, particularly in Oryza sativa (rice), as indicated by antibody catalog information . While the search results don't provide detailed functional differences between PEX11-5 and other isoforms, research on other PEX11 family members shows functional specialization. In mammals, PEX11α and PEX11β both behave as integral peroxisomal membrane proteins but may have distinct regulatory mechanisms . PEX11β in particular has been extensively studied and shows strong peroxisome-proliferating activity. In yeast studies, related PEX11 proteins (Pex11p, Pex25p, and Yor193p) demonstrate different interaction patterns - Yor193p interacts with Pex25p and itself, Pex25p interacts with Yor193p and itself, while Pex11p primarily interacts with itself . These interaction differences suggest functional specialization that might extend to plant PEX11 isoforms as well.

What detection methods work best with PEX11-5 antibody for peroxisome visualization?

Based on research methodologies used with other PEX11 antibodies, several detection approaches are effective for peroxisome visualization:

For optimal results, cells should be fixed with formaldehyde (typically 3.7%) and spheroblasted before immunolabeling. Fluorescent secondary antibodies (Cy5-conjugated or similar) provide excellent visualization when imaged using appropriate filter sets (e.g., 640/30 band pass filters for excitation and 690/50 band pass filters for emission) . When quantifying peroxisome abundance, manual counting in randomly captured cells using imaging software such as Imaris is recommended, with a minimum sample size of 150 cells per condition .

How should researchers design experiments to study PEX11-5 phosphorylation state and its impact on peroxisome proliferation?

Phosphorylation plays a critical role in regulating PEX11 activity. Based on research with yeast Pex11p, phosphorylation-dependent regulation directly controls peroxisome dynamics . To study PEX11-5 phosphorylation:

• Phosphorylation site identification:

  • Perform site-directed mutagenesis of putative phosphorylation motifs using PCR-based strategies

  • Create phosphomimetic (e.g., serine/threonine to aspartate) and phospho-deficient (serine/threonine to alanine) mutants

  • Confirm mutations by sequencing the entire PEX11 ORF and flanking regions

• Functional analysis:

  • Express wild-type and mutant constructs in appropriate cell systems

  • Compare peroxisome morphology, number, and distribution between phosphomimetic and phospho-deficient mutants

  • Quantify peroxisome numbers per cell (minimum 150 cells per condition)

• Phosphorylation detection:

  • Use phospho-specific antibodies if available

  • Perform phosphatase treatments followed by mobility shift analysis on SDS-PAGE

  • Consider mass spectrometry to identify precise phosphorylation sites

When designing these experiments, it's essential to include proper controls, including wild-type PEX11-5 expression and unrelated peroxisomal membrane protein (PMP) controls to ensure observed effects are specific to phosphorylation status rather than protein overexpression .

What controls are necessary when studying the effect of PEX11-5 on peroxisome proliferation?

When investigating PEX11-5's role in peroxisome proliferation, several critical controls must be included:

• Negative expression controls:

  • Untransfected/untreated cells to establish baseline peroxisome numbers

  • Expression of unrelated peroxisomal membrane proteins (e.g., PMP34) to control for effects of protein overexpression

• Metabolic pathway controls:

  • Experiments in cells with intact and defective peroxisomal β-oxidation pathways to determine whether proliferation effects are metabolism-dependent

  • Studies have shown PEX11β can promote peroxisome division even in cells defective in all known peroxisomal metabolic activities (e.g., PBD005 cells)

• Temporal controls:

  • Time-course experiments to distinguish between early events (protein localization, 1.5-2h), intermediate events (peroxisome elongation, 4-8h), and late events (increased abundance, 24-48h)

• Expression level controls:

  • Titration of expression levels to determine dose-dependency

  • Monitoring of protein levels via immunoblotting with calibrated antibody concentrations (typically 0.25 μg/ml for immunoblotting)

• Specificity controls:

  • Comparison with other PEX11 isoforms to determine functional specificity

  • Evaluation in different cell types to ensure consistent function across cellular contexts

Proper quantification is essential - peroxisome numbers should be counted in at least 150 randomly selected cells per condition using appropriate imaging software to ensure statistical significance .

How can researchers distinguish between direct and indirect effects of PEX11-5 on peroxisome metabolism?

Distinguishing direct from indirect effects of PEX11 proteins on peroxisome metabolism represents a significant challenge in the field. Research with PEX11β has demonstrated that its effects on peroxisome proliferation are independent of peroxisomal metabolism, while metabolic defects observed in PEX11-deficient cells are likely indirect consequences . To determine whether PEX11-5 directly or indirectly affects peroxisome metabolism:

• Genetic approach:

  • Generate PEX11-5 knockout/knockdown models and assess specific metabolic pathways

  • Create double mutants lacking both PEX11-5 and key metabolic enzymes to test for epistatic relationships

  • Use heterozygous diploid strains with deletions in PEX11-5 and related genes (similar to approaches used with Pex11p/Pex25p/Yor193p)

• Metabolic profiling:

  • Measure multiple peroxisomal metabolic activities in PEX11-5 deficient cells

  • Analyze fatty acid oxidation, particularly medium-chain fatty acids (MCFAs)

  • Compare metabolic defects with structural/numerical changes in peroxisomes

• Expression system approach:

  • Express PEX11-5 in cells lacking peroxisomal metabolic functions

  • Determine if peroxisome proliferation occurs despite metabolic deficiencies

  • Similar to studies showing PEX11β induced 30-fold increase in peroxisome abundance in PBD005 cells lacking peroxisomal β-oxidation

• Membrane structure analysis:

  • Examine peroxisomal membrane properties using electron microscopy

  • Analyze membrane lipid composition in presence/absence of PEX11-5

  • Test hypothesis that PEX11-5 affects metabolism indirectly by altering membrane structure

These approaches, combined with proper controls, can help determine whether metabolic alterations observed in PEX11-5 manipulated cells are direct consequences of PEX11-5 function or indirect effects resulting from changes in peroxisome abundance or structure.

What are the optimal fixation and immunostaining protocols for PEX11-5 antibody in different cell types?

Successful immunodetection of PEX11 proteins requires careful optimization of fixation and staining protocols. Based on methodologies used with other PEX11 antibodies:

• Fixation protocol:

  • Add 0.1 volume of 37% formaldehyde directly to the culture medium

  • For yeast cells, spheroplast the cells after fixation

  • For mammalian cells, fix with 4% paraformaldehyde for 20 minutes at room temperature

• Antibody optimization:

  • Primary antibody concentration: Use affinity-purified antibodies at 2.5 μg/ml for immunofluorescence (10× higher than for immunoblotting)

  • Secondary antibody selection: Cy5-conjugated secondary antibodies work well for fluorescence microscopy

  • Blocking: 1-3% BSA in PBS for 30-60 minutes prior to antibody incubation

• Cell-type specific considerations:

• Co-staining optimization:

  • For co-visualization with peroxisome markers, include catalase antibodies or PTS1-tagged fluorescent proteins

  • For ER co-localization studies, include ER markers such as Rtn1p-mRFP

  • Use appropriate filter sets: 470/40 (excitation) and 525/50 (emission) for GFP; 546/12 (excitation) and 575-640 (emission) for RFP; 640/30 (excitation) and 690/50 (emission) for Cy5

• Image acquisition:

  • Capture z-stacks at 300-nm intervals

  • Perform 3D deconvolution for optimal visualization

  • Use maximum intensity projections for final image display

How can researchers troubleshoot weak or nonspecific signals when using PEX11-5 antibody?

When encountering weak or nonspecific signals with PEX11-5 antibody, systematic troubleshooting is essential:

• Weak signal troubleshooting:

  • Antibody concentration: Increase concentration incrementally (start with 2-5× increase)

  • Incubation time: Extend primary antibody incubation (overnight at 4°C)

  • Detection system: Switch to more sensitive detection methods (amplification systems like tyramide signal amplification)

  • Fixation: Test alternative fixation methods (methanol vs. paraformaldehyde)

  • Antigen retrieval: Apply gentle heat-mediated or enzymatic antigen retrieval

  • Expression level: Verify target protein expression levels by RT-PCR

• Nonspecific signal troubleshooting:

  • Blocking: Increase blocking agent concentration (3-5% BSA or 5-10% normal serum)

  • Washing: Add more extensive washing steps with higher salt concentration

  • Antibody specificity: Pre-absorb antibody with control lysates or perform peptide competition

  • Secondary antibody: Test different secondary antibodies or directly conjugated primary

  • Controls: Include knockout/knockdown samples as negative controls

• Technical considerations:

  • Storage conditions: Ensure proper antibody storage (-20°C, avoid freeze-thaw cycles)

  • Sample preparation: Optimize protein extraction protocols for membrane proteins

  • Background reduction: Include detergents (0.1% Tween-20) in washing buffers

  • Signal-to-noise: Adjust imaging parameters (exposure, gain) for optimal contrast

Remember that antibody recognition can be affected by the state of the protein (native vs. denatured). Some PEX11 antibodies (like Q23 described in the literature) recognize only denatured protein, while others (like Q8 and P85) recognize both native and denatured forms . Testing the antibody in multiple applications (immunoblotting, immunofluorescence, immunoprecipitation) can help determine its optimal use conditions.

What methods provide the most accurate quantification of peroxisome proliferation when using PEX11-5 antibody?

Accurate quantification of peroxisome proliferation is critical for research involving PEX11 proteins. Based on established methodologies:

• Manual counting approach:

  • Count peroxisomes per cell section in at least 150 randomly captured cells

  • Use spot counting tools in imaging software like Imaris

  • Report as peroxisomes per cell section (pps)

  • Examples from literature: wild-type cells (230 ± 52 pps) vs. PEX11β−/− cells (128 ± 32 pps)

• Automated analysis methods:

  • Develop automated image analysis workflows using ImageJ/Fiji or CellProfiler

  • Standardize threshold settings and object size/circularity parameters

  • Validate automated counts against manual counts for subset of images

• Transmission electron microscopy (TEM):

  • Provides high-resolution analysis of peroxisome morphology

  • Apply morphometric analysis using algorithms developed by Weibel and Bolender

  • Measure peroxisome size, number, and distribution at ultrastructural level

• Biochemical quantification:

  • Measure peroxisome-specific enzyme activities as proxy for peroxisome abundance

  • Perform subcellular fractionation and quantify peroxisomal marker proteins

  • Use flow cytometry with peroxisome-targeted fluorescent proteins

• Standardization and statistical considerations:

For maximally reliable results, researchers should employ multiple complementary approaches and report both means and standard deviations. Time-course experiments are particularly valuable, as PEX11-mediated peroxisome proliferation occurs in distinct phases (localization at 1.5-2h, elongation at 4-8h, increased abundance at 24-48h) .

How can researchers distinguish between the effects of PEX11-5 on peroxisome size versus number?

PEX11 proteins affect both peroxisome number and morphology, making it important to distinguish between these effects when studying PEX11-5:

• Combined morphometric analysis:

  • Measure both parameters independently: count total peroxisome number per cell and measure individual peroxisome size

  • Calculate total peroxisomal volume/area per cell (size × number)

  • Compare distributions of peroxisome sizes rather than just averages

• Time-course studies:

  • Track changes in morphology over time following PEX11-5 manipulation

  • PEX11 overexpression typically causes initial elongation (4-8h) followed by increased number (24-48h)

  • Use live-cell imaging with peroxisome markers (e.g., fluorescent PTS1-tagged proteins)

• Ultrastructural analysis:

  • Employ transmission electron microscopy for high-resolution analysis

  • Distinguish between single enlarged peroxisomes and clustered normal-sized peroxisomes

  • Measure membrane surface area and matrix volume separately

• Genetic approach:

  • Compare PEX11-5 effects with mutations in genes specifically affecting fission (e.g., DRP1/DLP1) or fusion

  • Use double mutants to determine epistatic relationships

  • These analyses can help determine whether PEX11-5 primarily affects division, fusion, or de novo formation

• Quantitative metrics to report:

This multi-parameter approach allows researchers to determine whether PEX11-5 primarily affects peroxisome division (increasing number, decreasing size), fusion (decreasing number, increasing size), or has more complex effects on peroxisome dynamics.

What experimental approaches can determine if PEX11-5 functions are conserved across different species?

Determining the evolutionary conservation of PEX11-5 functions requires systematic comparative studies:

• Sequence-based approaches:

  • Perform phylogenetic analysis of PEX11 family members across species

  • Identify conserved domains, particularly those involved in membrane interaction or self-oligomerization

  • Compare phosphorylation sites and other post-translational modification motifs

• Heterologous expression studies:

  • Express PEX11-5 in mutant cells lacking endogenous PEX11 from different species

  • Measure complementation of peroxisome morphology and abundance defects

  • Compare with other PEX11 isoforms from same and different species

• Interaction network analysis:

  • Use yeast two-hybrid or co-immunoprecipitation to identify binding partners

  • Compare interaction patterns between species (e.g., self-interaction vs. interaction with other proteins)

  • Similar to studies showing different interaction patterns between Pex11p, Pex25p, and Yor193p

• Domain swap experiments:

  • Create chimeric proteins containing domains from PEX11-5 and other PEX11 family members

  • Test functionality of chimeras to identify conserved functional domains

  • Map species-specific regulatory regions

• Cross-species experimental design:

When designing these experiments, it's important to account for species-specific differences in peroxisome biology. For example, plant peroxisomes have specialized functions in photorespiration, while mammalian peroxisomes are critical for very-long-chain fatty acid metabolism. The baseline peroxisome abundance and morphology also vary significantly between species and cell types, necessitating appropriate controls.

How should researchers interpret contradictory results between different experimental approaches when studying PEX11-5 function?

Contradictory results are common in complex biological systems and require careful interpretation:

• Methodological reconciliation:

  • Evaluate technical differences between contradictory studies (antibody specificity, fixation methods, quantification approaches)

  • Consider temporal factors - observations at different time points may reflect different stages of a dynamic process

  • PEX11 overexpression causes temporal progression from localization (1.5-2h) to elongation (4-8h) to increased abundance (24-48h)

• Biological context differences:

  • Assess cell type or organism-specific differences in peroxisome biology

  • Consider metabolic state - peroxisome proliferation is often regulated by metabolic conditions

  • Examine genetic background differences that might contain modifiers

• Integrated hypothesis development:

  • Develop models that accommodate seemingly contradictory observations

  • Similar to the revised model of PEX11 function that reconciled direct effects on division with indirect effects on metabolism

  • Consider whether PEX11-5 has multiple independent functions or context-dependent activities

• Critical evaluation of experimental approaches:

• Reconciliation examples from PEX11 research:

  • Initial hypotheses suggested PEX11 directly regulated MCFA oxidation, but later studies showed these effects were indirect consequences of altered peroxisome division

  • Phosphorylation studies revealed regulatory mechanisms explaining context-dependent activation

  • Interaction studies uncovered distinct protein-protein interaction networks for related proteins

When encountering contradictory results, researchers should design experiments that directly test competing hypotheses rather than simply accumulating more data using the same approaches. This might include creating specific mutants, performing genetic interaction screens, or developing new assays that can distinguish between alternative models.

How does the specificity and sensitivity of PEX11-5 antibody compare to antibodies against other PEX11 family members?

Based on available information about PEX11 antibodies:

• Epitope recognition characteristics:

  • PEX11 antibodies vary significantly in their ability to recognize native versus denatured forms

  • Some antibodies (like Q23) recognize only denatured protein, limiting their use to immunoblotting

  • Others (like Q8 and P85) recognize both native and denatured forms, enabling multiple applications

  • Researchers should determine whether PEX11-5 antibody recognizes conformational or linear epitopes

• Application-specific performance:

• Cross-reactivity considerations:

  • Test for cross-reactivity with other PEX11 family members

  • Validate specificity in knockout/knockdown systems

  • Consider peptide competition assays to confirm specificity

• Antibody generation strategies:

  • PEX11 antibodies have been successfully raised against specific peptides (e.g., amino acids 169-181 of Pex11p)

  • Alternatively, antibodies against larger fragments (e.g., amino acids 1-133) provide different epitope recognition

  • Affinity purification significantly improves specificity for all applications

When using commercial antibodies like PEX11-5 Antibody (CSB-PA722784XA01OFG) , researchers should perform validation experiments to determine optimal working conditions for their specific experimental system, as performance may vary between cell types and applications.

What distinct roles do different PEX11 family members play in peroxisome dynamics, and how can these be experimentally distinguished?

PEX11 family members appear to have both overlapping and distinct functions in peroxisome dynamics:

• Functional distinctions:

  • In mammals, different PEX11 isoforms (α, β, γ) show tissue-specific expression patterns

  • PEX11β knockout in mice causes embryonic lethality, suggesting critical non-redundant functions

  • In yeast, related proteins (Pex11p, Pex25p, Yor193p) show different interaction patterns - Yor193p interacts with Pex25p and itself, Pex25p interacts with Yor193p and itself, while Pex11p interacts only with itself

• Experimental approaches to distinguish functions:

  • Single and combinatorial knockouts/knockdowns to identify unique and redundant functions

  • Domain swapping between family members to map functional regions

  • Interaction network mapping using yeast two-hybrid or co-immunoprecipitation

  • Expression pattern analysis across tissues, developmental stages, or metabolic conditions

• Regulatory differences:

  • Different PEX11 family members may be regulated by distinct mechanisms (transcriptional, post-translational)

  • Phosphorylation-dependent regulation has been demonstrated for some PEX11 proteins

  • Metabolic responsiveness varies between isoforms

• Experimental design for functional discrimination:

• Plant-specific considerations:

  • Plants typically have more PEX11 isoforms than mammals or yeast

  • PEX11-5 in rice (Oryza sativa) likely has specific functions related to plant peroxisome biology

  • Plant peroxisomes have specialized roles in photorespiration, β-oxidation, and hormone metabolism

Understanding the distinct functions of PEX11 family members requires systematic comparative studies, ideally combining genetic, biochemical, and imaging approaches in appropriate model systems.

How can researchers design experiments to study the interaction between PEX11-5 and other peroxisome biogenesis factors?

Investigating interactions between PEX11-5 and other peroxisome biogenesis factors requires systematic approaches:

• Protein-protein interaction studies:

  • Yeast two-hybrid screening to identify potential interaction partners

  • Similar to studies showing Pex11p self-interaction and distinct patterns for related proteins

  • Co-immunoprecipitation using PEX11-5 antibody to pull down complexes from native cellular extracts

  • Bimolecular fluorescence complementation (BiFC) to visualize interactions in living cells

  • Proximity labeling approaches (BioID, APEX) to identify proteins in close proximity to PEX11-5

• Genetic interaction analysis:

  • Create heterozygous diploid strains with deletions in PEX11-5 and other peroxins

  • Similar to approaches used with Pex11p/Pex25p/Yor193p

  • Screen for synthetic lethality/sickness to identify functional relationships

  • Suppressor screens to identify factors that can compensate for PEX11-5 deficiency

• Temporal-spatial dynamics:

  • Analyze recruitment order of different factors during peroxisome biogenesis

  • Use live-cell imaging with fluorescently tagged proteins

  • Determine whether PEX11-5 functions early (biogenesis) or late (division) in the pathway

• Structural biology approaches:

  • Analyze membrane topology and identify critical interaction domains

  • Create deletion constructs to map interaction surfaces

  • Perform cross-linking studies to capture transient interactions

• Experimental design table:

• Specific interactions to investigate:

  • PEX11-5 self-interaction (oligomerization)

  • Interaction with membrane dynamics machinery (e.g., DRP1/Vps1p)

  • Association with other peroxins involved in import (PEX3, PEX19) or division

  • Potential interactions with metabolic enzymes

These approaches will help determine how PEX11-5 fits into the larger network of peroxisome biogenesis factors and whether its interactions differ significantly from other PEX11 family members.