The RAB40AL Antibody is a polyclonal antibody designed to detect the Ras-related protein Rab-40A-like (RAB40AL), a member of the Rab GTPase family. It is primarily used in research to study intracellular vesicle trafficking, protein sorting, and cellular homeostasis. RAB40AL contains a suppressor of cytokine signaling (SOCS) box, enabling its interaction with the Cullin5 (CRL5) complex, which mediates ubiquitination of target proteins .
RAB40AL is implicated in:
Vesicle Trafficking: Regulates membrane dynamics and protein sorting via interaction with CRL5 .
Ubiquitination and Degradation: Acts as a substrate-recognition component in E3 ligase complexes, targeting proteins for proteasomal degradation .
Cell Migration: Modulates focal adhesion dynamics and invadopodia formation in cancer cells .
Recent studies reveal RAB40AL’s role in:
AMBRA1 Ubiquitination: Rab40/CRL5 complexes ubiquitinate AMBRA1, altering its transcriptional activity without degrading it. This crosstalk regulates genes involved in cell adhesion and migration .
Bidirectional Signaling: AMBRA1/CRL4 complexes reciprocally influence Rab40/CRL5 activity, highlighting a complex interplay between ubiquitination and transcription .
Martin-Probst Syndrome: Missense mutations in RAB40AL (e.g., p.D59G) disrupt cytoplasmic localization and stability, leading to developmental disorders .
Neurodegenerative Diseases: Dysregulation of RAB40AL may contribute to lysosomal storage diseases or protein mislocalization disorders .
Optimal Detection: Western blot protocols require denaturing conditions, while immunofluorescence demands permeabilization (e.g., 0.2% Triton X-100) and blocking with 10% goat serum .
Cross-Reactivity: Limited to human samples; no orthologs identified in rodents or zebrafish .
Stability: Store at -20°C to maintain activity; avoid repeated freeze-thaw cycles.
RAB40AL antibodies are critical for:
RAB40AL (also known as RAB40A-like, MRXSMP, RAR2, or RLGP) is a member of the Rab GTPase family involved in intracellular protein trafficking and vesicular transport systems. It functions as a key regulatory protein in cellular homeostasis through its involvement in protein sorting and vesicle trafficking between cellular compartments . Unlike many other Rab proteins, RAB40AL contains a SOCS box domain, which enables it to function as a substrate-recognition component of SCF-like ECS (Elongin-Cullin-SOCS-box protein) E3 ubiquitin ligase complexes . These complexes mediate the ubiquitination and subsequent proteasomal degradation of target proteins, suggesting RAB40AL plays a dual role in both trafficking and protein degradation pathways. The protein shows expression across multiple tissues including brain, lung, heart, skeletal muscle, kidney, and liver, indicating its broad physiological importance .
Functionally, RAB40AL's role in vesicular transport positions it as a potentially important player in neurodegenerative disorders and lysosomal storage diseases, where protein mislocalization and trafficking defects are common pathological features . Its interaction with the ubiquitin-proteasome system further suggests involvement in protein quality control mechanisms. Similar to other Rab40 family members, RAB40AL likely participates in cytoskeletal organization and cell migration through interactions with effector proteins, though specific mechanisms for RAB40AL are still being elucidated compared to better-characterized family members like Rab40b and Rab40c.
When selecting a RAB40AL antibody for research applications, several technical specifications must be carefully evaluated to ensure experimental success. Host species is a primary consideration, with rabbit-derived polyclonal antibodies being commonly used for RAB40AL detection . The clonality of the antibody affects its specificity and application range – polyclonal antibodies recognize multiple epitopes and generally provide higher sensitivity, while monoclonal antibodies offer greater specificity for a single epitope. Researchers should verify the antibody's reactivity with their species of interest, as many commercial RAB40AL antibodies are primarily validated against human samples .
Application compatibility represents another critical specification, with different antibodies optimized for specific techniques such as Western blot (WB), immunohistochemistry (IHC), enzyme-linked immunosorbent assay (ELISA), or immunofluorescence (IF) . The recommended dilution ranges vary significantly by application – for example, the PACO59876 antibody recommends dilutions of 1:2000-1:10000 for ELISA and 1:20-1:200 for IF applications . Storage buffer composition (typically containing preservatives like Proclin 300 and stabilizers like glycerol) and purification method (commonly Protein G purification) affect antibody stability and performance over time . Researchers should also consider whether conjugated versions (such as APC-conjugated antibodies) might be required for certain applications like flow cytometry, though most RAB40AL antibodies are available in non-conjugated forms .
Optimizing Western blotting for RAB40AL detection requires careful consideration of several methodological factors to ensure specific and sensitive protein identification. Begin with proper sample preparation by using an appropriate lysis buffer containing protease inhibitors to prevent protein degradation, as RAB40AL has a molecular weight of approximately 31.2 kDa and can be susceptible to proteolytic cleavage . During protein separation, choose an appropriate percentage acrylamide gel (10-12%) that provides optimal resolution in the 25-35 kDa range where RAB40AL migrates. Use efficient transfer conditions with methanol-containing buffers for PVDF membranes or methanol-free buffers for nitrocellulose membranes to ensure complete protein transfer.
Blocking conditions significantly impact background and signal quality – typically, 5% non-fat dry milk or BSA in TBST works well for RAB40AL detection, but optimization may be needed depending on the specific antibody used . Antibody dilution represents a critical parameter for optimization, with most RAB40AL antibodies requiring dilutions in the range of 1:500-1:2000 for Western blotting applications . Incubate primary antibodies overnight at 4°C to maximize specific binding while minimizing background. For detection systems, HRP-conjugated secondary antibodies with enhanced chemiluminescence (ECL) provide good sensitivity for RAB40AL, though fluorescent secondary antibodies may offer advantages for multiplex detection or quantification.
When troubleshooting RAB40AL detection, common issues include non-specific bands, which can be addressed by increasing antibody dilution or using more stringent washing conditions, and weak signals, which might require longer exposure times or higher protein loading. Given that RAB40AL contains a SOCS box domain that participates in protein-protein interactions, denaturing conditions must be carefully controlled to ensure proper epitope exposure while maintaining antibody recognition.
Comprehensive validation of RAB40AL antibodies requires a strategic set of controls to ensure specificity, sensitivity, and reproducibility in experimental applications. Positive controls should include samples with confirmed RAB40AL expression such as brain, lung, heart, skeletal muscle, kidney, or liver tissue lysates, as these tissues have demonstrated detectable expression of the protein . Cell lines known to express RAB40AL endogenously provide another source of positive controls, while recombinant human RAB40AL protein (available from sources like ABIN7551236 or ABIN3086973) offers a defined positive control with known concentration . Negative controls are equally important and should include samples from knockout or knockdown systems where RAB40AL expression has been genetically ablated or reduced, respectively.
Antibody specificity can be further validated through peptide competition assays, where pre-incubation of the antibody with excess immunizing peptide should eliminate specific binding in subsequent applications . For Western blotting applications, molecular weight verification is essential – RAB40AL should appear at approximately 31.2 kDa, though post-translational modifications may alter its apparent molecular weight . Cross-reactivity testing against related family members (such as RAB40A, RAB40B, and RAB40C) helps establish specificity within the Rab family, especially important given the high sequence similarity among these proteins.
Method-specific controls should be included based on the application: for immunohistochemistry, secondary-only controls assess background from the detection system; for immunoprecipitation, beads-only controls account for non-specific binding to the matrix; for immunofluorescence, competitive peptide blocking and subcellular localization pattern assessment help confirm antibody specificity . Reproducibility should be demonstrated through technical and biological replicates, with consistent results across different lots of the same antibody when possible.
RAB40AL antibodies provide powerful tools for investigating the protein's integration within SCF-like E3 ubiquitin ligase complexes through multiple complementary approaches. Co-immunoprecipitation (co-IP) experiments represent the cornerstone method, where RAB40AL antibodies can pull down the protein along with its interacting partners such as Cullin5, Elongin B/C, and Rbx2 . When designing these experiments, researchers should use mild lysis conditions (containing 0.5-1% NP-40 or Triton X-100) to preserve protein complexes, and pre-clear lysates with appropriate control IgG to reduce non-specific binding. The IP efficiency can be enhanced by crosslinking the antibody to protein A/G beads, which prevents IgG contamination in the eluted samples and improves signal-to-noise ratio when detecting interacting partners.
Proximity ligation assays (PLA) offer a complementary approach for detecting RAB40AL interactions in situ within cells or tissues. This technique combines antibody recognition with rolling circle amplification to visualize protein-protein interactions with subcellular resolution. By using a RAB40AL antibody in combination with antibodies against suspected binding partners (such as Cullin5), researchers can confirm interactions and map their subcellular localization . For this application, antibody pairs from different host species must be selected to allow species-specific secondary antibody recognition.
Advanced proteomic approaches can be employed by using RAB40AL antibodies for immunoprecipitation followed by mass spectrometry (IP-MS) to identify novel interaction partners in an unbiased manner. This technique requires highly specific antibodies to minimize false positives from contaminant proteins. Stable isotope labeling with amino acids in cell culture (SILAC) combined with IP-MS provides quantitative comparison of interaction partners across different cellular conditions. Additionally, bimolecular fluorescence complementation (BiFC) assays can validate direct interactions by fusing protein fragments to RAB40AL and its suspected partners, with interaction bringing the fragments together to produce fluorescence.
Investigating RAB40AL-mediated ubiquitination requires specialized methodological approaches that integrate antibody-based detection with ubiquitin pathway analysis. In vitro ubiquitination assays represent a fundamental approach, combining purified components (E1, E2, the RAB40AL-containing E3 complex, ubiquitin, ATP, and substrate proteins) to reconstitute the ubiquitination reaction in a controlled environment . These assays can be monitored by Western blotting using RAB40AL antibodies in combination with substrate-specific and ubiquitin-specific antibodies. Time-course experiments can reveal the kinetics of ubiquitination, while substituting wild-type ubiquitin with mutant versions (e.g., K48R or K63R) helps determine the type of ubiquitin chains being formed.
For cellular ubiquitination studies, cells can be transfected with tagged versions of RAB40AL and ubiquitin, treated with proteasome inhibitors like MG132 to prevent degradation of ubiquitinated proteins, and then analyzed by co-immunoprecipitation followed by Western blotting . The polyubiquitination of RAB40AL itself or its substrates appears as high-molecular-weight smears above the expected protein size. When transfecting cells with both FLAG-Rab40c and Myc-Ub, immunoprecipitation with anti-FLAG antibodies followed by immunoblotting with anti-Myc antibodies can detect ubiquitinated species, as demonstrated with the related Rab40c protein .
To identify specific ubiquitination substrates of RAB40AL, comparative proteomics approaches using stable isotope labeling (SILAC) coupled with tandem ubiquitin binding entities (TUBEs) enrichment and mass spectrometry can be employed . This approach compares the ubiquitinome in control versus RAB40AL-depleted or overexpressing cells to identify differentially ubiquitinated proteins. For studying the structural basis of RAB40AL-substrate recognition, hydrogen-deuterium exchange mass spectrometry (HDX-MS) or cross-linking mass spectrometry (XL-MS) can map interaction interfaces. Additionally, CRISPR-Cas9 gene editing to create RAB40AL SOCS box domain mutants provides a powerful tool for assessing the functional significance of ubiquitination activity in cellular processes.
Comparative analysis of RAB40 family members requires careful experimental design to distinguish their unique and overlapping functions despite high sequence homology. Antibody specificity verification is crucial when studying RAB40AL alongside RAB40A, RAB40B, and RAB40C, as antibody cross-reactivity can confound results due to high sequence similarity . Western blotting with isoform-specific antibodies against endogenous proteins, supplemented by overexpression systems with tagged versions, can help establish expression patterns across different cell types and tissues. Quantitative PCR provides complementary information about mRNA expression levels of each family member, though post-transcriptional regulation may result in discrepancies between mRNA and protein levels.
Protein interaction network mapping through techniques like BioID (proximity-dependent biotin identification) or IP-MS can identify unique and overlapping interaction partners among RAB40 family members . For example, while all RAB40 proteins interact with Cullin5 through their SOCS box domains, they likely recruit different substrate proteins for ubiquitination, defining their functional specificity. Rescue experiments, where the phenotypes of one RAB40 family member's depletion are assessed for rescue by overexpression of other family members, provide direct evidence of functional redundancy or specificity. These approaches collectively build a comparative functional map of RAB40 family members, positioning RAB40AL within this important protein family.
When working with pathological specimens, researchers must account for altered protein expression patterns and potential background issues. Control tissues should include both normal samples and disease-relevant tissues with verified RAB40AL expression status. The choice between chromogenic and fluorescent detection systems depends on research goals – chromogenic methods (like DAB) provide permanent preparations suitable for archival specimens, while fluorescent methods offer higher sensitivity and the ability to perform multiplex staining to correlate RAB40AL with other disease markers . For multiplex immunofluorescence, careful selection of primary antibodies from different host species is essential to avoid cross-reactivity.
Quantification approaches for RAB40AL in tissues range from semi-quantitative scoring systems (assessing staining intensity and percentage of positive cells) to sophisticated digital image analysis with automated scoring algorithms. Laser capture microdissection combined with Western blotting or mass spectrometry can provide region-specific quantification in heterogeneous tissues. For investigations spanning multiple tissue types or comparing normal versus diseased states, tissue microarrays (TMAs) offer high-throughput analysis opportunities. When studying RAB40AL in neurodegenerative conditions or lysosomal storage diseases, co-staining with cell type-specific markers, disease markers, and organelle markers helps establish pathological correlations .
Researchers frequently encounter several challenges when working with RAB40AL antibodies, each requiring specific troubleshooting approaches. Non-specific binding represents a common issue, manifesting as multiple unexpected bands in Western blots or diffuse staining patterns in immunohistochemistry . This can be addressed by increasing antibody dilution (starting with a 2-5 fold increase from manufacturer recommendations), employing more stringent washing conditions with higher salt concentration or detergent in wash buffers, or using alternative blocking agents such as fish gelatin or commercial blocking solutions when conventional blocking with BSA or milk proves insufficient. Pre-absorbing the antibody with control tissue lysates that lack RAB40AL expression can also help reduce non-specific binding.
Weak or absent signals despite confirmed target expression indicate sensitivity issues. Researchers can attempt signal enhancement by increasing antibody concentration, extending incubation times (overnight at 4°C rather than 1-2 hours at room temperature), or employing signal amplification systems like biotin-streptavidin or tyramide signal amplification (TSA) . For Western blotting applications, increasing protein loading (up to 50-100 μg per lane) or using more sensitive detection reagents like enhanced chemiluminescence (ECL) Plus or femto-sensitivity substrates may improve detection. Sample preparation should be optimized to ensure efficient protein extraction, particularly for membrane-associated proteins like RAB40AL, by using detergent-based lysis buffers containing 1-2% Triton X-100 or NP-40.
Batch-to-batch variability represents another significant challenge with polyclonal antibodies against RAB40AL. Researchers should maintain detailed records of antibody lot numbers and performance characteristics, ideally validating each new lot against previously validated lots . Creating internal standards or calibrators (such as recombinant RAB40AL protein or consistently performing cell lysates) provides reference points for comparing antibody performance across experiments. When working with difficult samples like formalin-fixed tissue, epitope retrieval conditions must be empirically optimized with variables including buffer composition (citrate vs. EDTA), pH (6.0 vs. 9.0), temperature, and duration to maximize antibody binding while preserving tissue integrity.
Designing experiments to differentiate between highly homologous RAB family proteins requires strategic approaches to overcome potential cross-reactivity and ensure target specificity. Antibody validation represents the foundation of specific detection, ideally employing antibodies raised against unique regions of RAB40AL that differ from other RAB family members, particularly RAB40A, RAB40B, and RAB40C . Rigorous validation should include testing against cells or tissues overexpressing each RAB family member individually to establish cross-reactivity profiles. Peptide competition assays using synthetic peptides corresponding to the immunizing epitopes can confirm antibody specificity, with signal elimination indicating specific binding.
Genetic manipulation provides powerful tools for validation and functional discrimination. CRISPR-Cas9 knockout or siRNA knockdown of RAB40AL followed by antibody staining can confirm signal specificity, with signal loss in depleted samples confirming antibody specificity . Conversely, overexpression systems using tagged versions (FLAG, HA, or GFP) of different RAB proteins allow controlled expression levels and easy detection through tag-specific antibodies. When using overexpression systems, researchers should verify that tagging does not interfere with protein localization or function through careful comparison with endogenous protein behavior.
Multiple detection methods should be employed for comprehensive discrimination. While Western blotting can separate proteins by molecular weight, subtle size differences between RAB family members may not provide clear discrimination. Complementary approaches like quantitative RT-PCR with isoform-specific primers can distinguish expression at the mRNA level. Immunoprecipitation followed by mass spectrometry (IP-MS) offers definitive protein identification beyond antibody recognition . For functional discrimination, researchers can exploit known differences in interaction partners, subcellular localization, or response to stimuli among RAB family members. For example, if RAB40AL shows distinct binding to particular effector proteins or localizes to specific organelles compared to other family members, these characteristics can serve as discriminating features.
Accurate quantification of RAB40AL expression requires selection of appropriate methodological approaches based on experimental context and research questions. For protein-level quantification, Western blotting with densitometric analysis provides semi-quantitative assessment when normalized to loading controls like GAPDH, β-actin, or total protein staining with Ponceau S . To achieve more precise quantification, researchers should ensure linearity of signal by testing multiple loading amounts and exposure times, avoiding saturation that compromises quantitative analysis. For absolute quantification, standard curves generated using recombinant RAB40AL protein at known concentrations can convert relative values to absolute protein amounts.
ELISA-based approaches offer higher throughput and potentially greater sensitivity for RAB40AL quantification. Sandwich ELISA using two antibodies recognizing different epitopes provides specificity advantages, though commercial ELISA kits for RAB40AL may have limited availability . For absolute quantification, standard curves using recombinant RAB40AL are essential. When analyzing multiple samples across different experimental conditions, technical triplicates help establish measurement precision, while biological replicates address sample variability.
For tissue-based quantification, immunohistochemistry combined with digital image analysis provides spatial information alongside expression levels. Standardization using control slides with known expression levels enables cross-experiment comparisons. Multiplex immunofluorescence allows simultaneous quantification of RAB40AL alongside other proteins of interest, providing valuable co-expression data . For mRNA-level quantification, quantitative RT-PCR offers high sensitivity and specificity when designed with isoform-specific primers that distinguish RAB40AL from related family members. Digital droplet PCR (ddPCR) provides absolute quantification without standard curves, particularly valuable for low-abundance transcripts. RNA-sequencing approaches offer comprehensive transcriptome analysis but require sophisticated computational analysis to distinguish between highly similar RAB family members. When correlating mRNA and protein levels, researchers should account for potential discrepancies due to post-transcriptional regulation, protein stability differences, or technical variability between methods.
RAB40AL antibodies offer valuable tools for investigating potential roles in neurodegenerative pathologies, where vesicular trafficking and protein degradation pathways are frequently disrupted. Immunohistochemical analysis of post-mortem brain tissues from patients with various neurodegenerative conditions can reveal alterations in RAB40AL expression, localization, or post-translational modifications compared to age-matched controls . Such studies should include co-staining with disease-specific markers (such as amyloid-β or tau for Alzheimer's disease, α-synuclein for Parkinson's disease) to establish correlation with pathological features. These investigations benefit from quantitative image analysis to detect subtle changes across brain regions differentially affected by disease.
Cell-based models of neurodegeneration provide platforms for mechanistic studies using RAB40AL antibodies. Primary neuronal cultures or patient-derived induced pluripotent stem cells (iPSCs) differentiated into neurons can be subjected to disease-relevant stressors (oxidative stress, protein misfolding inducers) followed by immunofluorescence analysis of RAB40AL . Co-localization studies with markers for different organelles (endosomes, lysosomes, autophagosomes) can reveal potential disruptions in vesicular trafficking pathways. Live-cell imaging with fluorescently tagged RAB40AL constructs can complement antibody-based approaches to capture dynamic aspects of vesicle movement under normal and pathological conditions.
Molecular interaction studies using co-immunoprecipitation with RAB40AL antibodies can identify altered protein-protein interactions in disease models . Given RAB40AL's role in SCF-like E3 ubiquitin ligase complexes, such studies might reveal connections to protein degradation pathways frequently compromised in neurodegenerative diseases . Proximity ligation assays provide in situ verification of these interactions with subcellular resolution. For functional studies, manipulating RAB40AL levels (through overexpression or RNAi-mediated knockdown) in neuronal models while monitoring effects on protein aggregation, neurite outgrowth, or synapse formation can establish causal relationships. These approaches collectively position RAB40AL antibodies as valuable tools for exploring potential connections between vesicular trafficking, protein degradation, and neurodegenerative pathologies.
Advanced methodological approaches using RAB40AL antibodies are providing new insights into cell migration mechanisms and potential cancer connections. Live-cell imaging techniques combined with immunofluorescence staining allow researchers to correlate RAB40AL localization with dynamic cellular processes during migration . For these applications, antibodies must be carefully validated for specificity in immunofluorescence to distinguish RAB40AL from related family members that may also influence migration. Complementary approaches using fluorescently tagged RAB40AL constructs help overcome potential limitations of antibody accessibility to certain subcellular compartments during dynamic processes.
Three-dimensional cell culture models offer more physiologically relevant contexts for studying RAB40AL in migration and invasion. Immunofluorescence staining of spheroids or organoids with RAB40AL antibodies, combined with confocal or light-sheet microscopy, provides spatial information about protein distribution during collective cell migration . For invasion assays, cells migrating through extracellular matrix substitutes can be fixed and stained for RAB40AL along with cytoskeletal markers to assess potential correlations with invasive phenotypes. These approaches benefit from quantitative image analysis to detect subtle changes in protein localization or expression levels.
For mechanistic studies in cancer contexts, patient-derived xenograft models or tissue microarrays from cancer patients can be analyzed for RAB40AL expression and correlation with clinical features . Co-immunoprecipitation studies using RAB40AL antibodies may reveal cancer-specific interaction partners or post-translational modifications that alter protein function. Mass spectrometry-based proteomics following immunoprecipitation can identify the "interactome" of RAB40AL in normal versus cancer cells, potentially revealing novel therapeutic targets . For functional validation, CRISPR-Cas9-mediated gene editing to create RAB40AL knockouts or specific domain mutants in cancer cell lines, followed by phenotypic assays (migration, invasion, proliferation), can establish causal relationships. High-content screening approaches combining RAB40AL antibody staining with automated microscopy allow large-scale assessment of how drug treatments or genetic manipulations affect RAB40AL expression, localization, and function in cancer cells.
Integration of RAB40AL antibodies with single-cell technologies represents a frontier area enabling unprecedented resolution of protein expression and function heterogeneity. Single-cell Western blotting, a microfluidic platform that separates proteins from individual cells followed by antibody detection, allows quantitative assessment of RAB40AL expression across thousands of cells while preserving single-cell resolution . This technique is particularly valuable for analyzing rare cell populations or examining heterogeneity that might be masked in bulk analyses. Technical optimization includes determining the optimal antibody concentration and incubation conditions for microfluidic formats, where reagent volumes and diffusion kinetics differ from conventional Western blotting.
Mass cytometry (CyTOF) approaches using metal-conjugated RAB40AL antibodies enable simultaneous quantification of dozens of proteins in single cells, providing rich phenotypic information . This technique requires careful panel design to include markers that help define cell states or types alongside RAB40AL, allowing correlation of its expression with cellular identity or functional state. For imaging mass cytometry, the spatial dimension is preserved, enabling assessment of RAB40AL expression in the tissue architectural context at single-cell resolution. Both approaches require metal-conjugated antibodies, which may need custom development for RAB40AL if not commercially available.
Emerging spatial transcriptomics and proteomics technologies provide opportunities for integrating RAB40AL protein detection with transcriptome-wide analysis at near-single-cell resolution. Methods like Digital Spatial Profiling (DSP) can combine RAB40AL antibody staining with region-specific RNA and protein profiling, creating multidimensional datasets that link RAB40AL expression to broader molecular phenotypes with spatial context. For maximum sensitivity in challenging samples or rare cells, proximity extension assays (PEA) and proximity ligation assays (PLA) provide amplification-based detection of RAB40AL with potentially single-molecule sensitivity. Single-cell RNA sequencing coupled with protein detection (CITE-seq) using oligo-conjugated antibodies enables correlation between RAB40AL protein levels and transcriptome-wide gene expression in thousands of individual cells, though this requires custom conjugation of RAB40AL antibodies with DNA oligonucleotides if not commercially available.
Ubiquitination analysis represents a particularly relevant area for RAB40AL given its involvement in E3 ubiquitin ligase complexes . Experimental approaches include immunoprecipitation under denaturing conditions (to disrupt non-covalent interactions) followed by Western blotting with anti-ubiquitin antibodies. This technique has been successfully applied to related proteins like Rab40c, where FLAG-tagged protein was immunoprecipitated and blotted for co-transfected Myc-ubiquitin, revealing ubiquitination patterns . Site-directed mutagenesis of potential ubiquitination sites (lysine residues) followed by functional assays helps establish the significance of specific modification sites.
Additional PTMs such as prenylation, which affects membrane association of many Rab proteins, can be studied through metabolic labeling with prenyl precursors followed by RAB40AL immunoprecipitation and fluorography or click chemistry-based detection. For functional studies of PTM significance, comparison of wild-type RAB40AL with phosphomimetic (e.g., serine to glutamate) or phospho-deficient (serine to alanine) mutants in rescue experiments provides insights into how phosphorylation affects protein function. Similar approaches with ubiquitination-site mutants help establish the role of this modification. Temporal dynamics of modifications can be explored through time-course experiments following stimulation or inhibition of relevant pathways, with samples collected at different time points for immunoprecipitation and Western blot analysis with modification-specific antibodies.
Application | Recommended Dilution | Incubation Conditions | Sample Preparation | Detection Method | Common Challenges |
---|---|---|---|---|---|
Western Blot | 1:500-1:2000 | Overnight at 4°C | 10-50 μg protein/lane, denatured | HRP-conjugated secondary with ECL | Non-specific bands, weak signal |
Immunofluorescence | 1:20-1:200 | 1-3 hours at RT or overnight at 4°C | 4% PFA fixation, 0.2% Triton X-100 permeabilization | Fluorophore-conjugated secondary antibodies | Background fluorescence, weak signal |
Immunohistochemistry | 1:50-1:200 | 1-2 hours at RT or overnight at 4°C | FFPE sections, antigen retrieval | DAB or AEC chromogenic detection | Non-specific staining, variable epitope accessibility |
ELISA | 1:2000-1:10000 | 1-2 hours at RT | Purified protein or cell lysate | Colorimetric, fluorometric, or chemiluminescent | Limited sensitivity for low abundance samples |
Immunoprecipitation | 2-5 μg antibody/mg protein | Overnight at 4°C | Native lysis with 1% NP-40 or RIPA buffer | Western blot of precipitated proteins | Inefficient precipitation, co-precipitation of non-specific proteins |
This comprehensive table provides researchers with optimized conditions for different applications of RAB40AL antibodies based on published protocols and manufacturer recommendations . The conditions may require further optimization depending on the specific antibody clone and sample type.
This table summarizes the current knowledge about RAB40AL expression patterns across different tissues and commonly used cell lines based on available research data . Expression levels may vary based on physiological conditions and cellular states.