RAB44 Antibody: Selection, Validation & Application Guide

RAB44 Antibody is a research-grade immunological reagent designed to detect and study RAB44, an atypical large Rab GTPase involved in vesicular trafficking and immune cell function.

Product SKU

Ab349236

Target Protein

RAB44 (Ras-related protein Rab-44)

Protein Family

Rab GTPase superfamily

Recommended Applications

Western Blot (WB), Immunofluorescence (IF), Immunohistochemistry (IHC)

Supplier Reference

absea#OC-595

Storage Recommendation

Store at -20°C; avoid repeated freeze-thaw cycles

Introduction to RAB44 and Its Biological Significance

RAB44 belongs to the Rab GTPase superfamily, a large family of small GTP-binding proteins that are master regulators of intracellular vesicular trafficking. Unlike most canonical Rab proteins, RAB44 is an atypical, unusually large Rab GTPase that contains additional structural domains beyond the core GTPase fold, including a coiled-coil domain and an EF-hand-like motif, suggesting roles in calcium sensing and protein-protein interactions.

RAB44 is reported to be preferentially expressed in hematopoietic and immune cells, including mast cells, basophils, and eosinophils, where it has been implicated in the regulation of secretory lysosome exocytosis and degranulation. Disruption of RAB44 function may impact immune responses, making it a potentially relevant target in allergy, inflammation, and related disease research.

Using a validated RAB44 Antibody such as Ab349236 enables researchers to localize RAB44 protein within cells, quantify expression levels across tissue types, and assess changes in RAB44 under experimental conditions.

Antibody Selection and Experimental Design

Selecting the correct RAB44 antibody format and validating its performance are essential steps before integrating it into your experimental workflow. Key considerations include:

• Species Reactivity: Confirm that the antibody reacts with your species of interest (e.g., human, mouse, rat). Consult the Ab349236 datasheet for confirmed species cross-reactivity.
• Host Species and Conjugate: Choose between unconjugated primary antibodies or conjugated formats depending on your detection system. For multi-color immunofluorescence, ensure the host species of RAB44 Antibody does not conflict with other primaries in your panel.
• Application Compatibility: Different antibody clones and epitopes may perform differently across WB, IF, IHC, and flow cytometry. Always verify the application compatibility listed on the product datasheet before use.
• Controls: Include a positive control (a cell line or tissue known to express RAB44), a negative control (RAB44-knockout or isotype control), and a loading/housekeeping control for quantitative experiments.

For Ab349236, refer to the product-specific datasheet available from Aladdin Scientific for validated dilution ranges and recommended sample types.

Standard Protocols for Key Applications

The following outlines general best-practice protocols when using RAB44 Antibody (Ab349236). Always supplement with the specific instructions provided in the product datasheet.

Western Blot (WB)

1. Lyse cells or homogenize tissue in an appropriate RIPA or NP-40 lysis buffer supplemented with protease inhibitors.
2. Quantify protein using BCA or Bradford assay; load 20–40 µg total protein per lane on SDS-PAGE.
3. Transfer to PVDF or nitrocellulose membrane; block with 5% non-fat milk or BSA in TBST for 1 hour at room temperature.
4. Incubate with RAB44 Antibody (Ab349236) at the manufacturer-recommended dilution overnight at 4°C.
5. Wash 3× with TBST; incubate with appropriate HRP-conjugated secondary antibody for 1 hour at room temperature.
6. Detect signal using an ECL substrate; expect a band consistent with the predicted molecular weight of RAB44.

Immunofluorescence (IF)

1. Fix cells with 4% paraformaldehyde for 15 minutes; permeabilize with 0.1–0.3% Triton X-100 for 10 minutes.
2. Block with 5% normal serum for 1 hour; incubate with RAB44 Antibody (Ab349236) at recommended dilution overnight at 4°C.
3. Wash and apply fluorophore-conjugated secondary antibody; counterstain nuclei with DAPI.
4. Mount and image using a fluorescence or confocal microscope.

Note: Optimal dilutions must be determined empirically for each lot and application.

Troubleshooting Common Issues

Even with validated reagents, antibody experiments may require optimization. Below are common issues and suggested solutions when working with RAB44 Antibody:

Issue	Possible Cause	Suggested Action
No signal detected (WB)	RAB44 not expressed in chosen cell line; antibody dilution too high	Use a confirmed RAB44-positive cell line as positive control; titrate antibody concentration
High background	Insufficient blocking; antibody concentration too high; secondary antibody cross-reactivity	Extend blocking time; reduce primary antibody concentration; use species-adsorbed secondary
Multiple non-specific bands (WB)	Protein degradation; incomplete denaturation	Ensure fresh protease inhibitors in lysis buffer; confirm denaturing SDS-PAGE conditions
Weak or diffuse IF signal	Over-permeabilization; fixation incompatibility with epitope	Optimize fixation/permeabilization conditions; try alternative fixative (e.g., methanol for some epitopes)
Inconsistent results between lots	Lot-to-lot variation	Titrate each new lot; request lot-specific validation data from Aladdin Scientific

Storage, Handling, and Quality Assurance

Proper storage and handling of RAB44 Antibody (Ab349236) are critical to maintaining reagent integrity and reproducibility across experiments.

• Storage Temperature: Store at -20°C upon receipt. For antibodies supplied in glycerol-containing buffers, storage at -20°C is typically sufficient without freezing solid.
• Aliquoting: Upon first use, prepare single-use aliquots to minimize the number of freeze-thaw cycles, which can progressively degrade antibody performance.
• Working Solutions: Freshly prepare diluted antibody solutions in blocking buffer immediately before use; do not store diluted antibody for extended periods.
• Avoid Contamination: Use aseptic technique when handling antibody stock; do not introduce sodium azide into samples that will be used in cell-based assays, as it is cytotoxic.
• Expiry and Quality Control: Observe the expiry date on the product label. Aladdin Scientific's Ab349236 undergoes quality control testing; contact technical support if unexpected results are obtained.

For procurement inquiries, bulk orders, or lot-specific Certificate of Analysis (CoA) requests, please contact Aladdin Scientific customer service.

Frequently asked questions

What is RAB44 and why is it a target for antibody-based research?

RAB44 is an atypical, large member of the Rab GTPase superfamily involved in regulating vesicular trafficking, particularly in immune cells such as mast cells and eosinophils. Its unique domain architecture and restricted expression pattern make it a target of interest in studies of degranulation, lysosomal secretion, and immune cell biology.

Which applications is the RAB44 Antibody (Ab349236) validated for?

Ab349236 is intended for use in common immunological detection applications including Western Blot (WB), Immunofluorescence (IF), and Immunohistochemistry (IHC). Please refer to the current product datasheet from Aladdin Scientific for the full list of validated applications, species reactivity, and recommended dilution ranges, as these may be updated with additional validation data.

How should I determine the optimal working dilution for RAB44 Antibody?

Always begin with the dilution range recommended in the Ab349236 product datasheet as a starting point. Perform a titration experiment using a known RAB44-positive sample to identify the dilution that gives the strongest specific signal with minimal background. Optimal dilution may vary depending on the application, sample type, detection system, and individual laboratory conditions.

What positive control samples are suitable for RAB44 Antibody experiments?

Cell lines or tissues known to express RAB44, such as hematopoietic cell lines of mast cell or eosinophil lineage, are appropriate positive controls. Consult the literature or publicly available gene expression databases (e.g., Human Protein Atlas) to identify suitable RAB44-expressing cell lines for your experimental system.

How do I request a Certificate of Analysis (CoA) for Ab349236?

You can request a lot-specific Certificate of Analysis for Ab349236 by contacting Aladdin Scientific's customer service team with your lot number. The CoA provides details of quality control testing performed on your specific antibody lot, including purity and functional test results.

References

1. Canonical reference on Rab GTPase superfamily structure and function — textbook-level knowledge. No specific external publication cited for RAB44.
2. Human Protein Atlas — RAB44 expression data (online resource). Accessed for expression pattern reference.
3. Aladdin Scientific product datasheet: RAB44 Antibody, SKU Ab349236 (absea#OC-595). Internal product documentation.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.