Recombinant Human MED14 Protein: Research Guide & Applications

Recombinant Human MED14 Protein is a recombinantly produced subunit of the Mediator transcriptional coactivator complex, essential for bridging gene-specific transcription factors with the RNA polymerase II basal transcription machinery.

Protein Name

Recombinant Human MED14 Protein

Gene Name

MED14 (also known as DRIP150, RGR1)

Biological Function

Core subunit of the Mediator complex; essential scaffold for Mediator assembly and transcriptional coactivation

Species

Human (Homo sapiens)

Application

In vitro transcription assays, protein-protein interaction studies, structural biology, and coactivator reconstitution experiments

Storage Recommendation

Avoid repeated freeze-thaw cycles; store at -80°C for long-term stability (verify exact conditions with product datasheet)

SKU

rp366336

Biological Background and Function of MED14

MED14, also referred to as DRIP150 or RGR1, is a large scaffold subunit of the Mediator complex, a highly conserved multi-subunit coactivator that plays a central role in eukaryotic RNA polymerase II (Pol II)-dependent transcription. The Mediator complex acts as a molecular bridge between upstream transcription activators bound to enhancer or promoter elements and the general transcription machinery assembled at core promoters.

MED14 is considered one of the most critical structural components of the Mediator, as it functions as an organizational scaffold that stabilizes interactions among multiple Mediator subunits. Studies in model organisms and human cells indicate that MED14 is indispensable for the integrity of the Mediator complex and for robust transcriptional activation across a wide range of gene programs. Loss of MED14 function leads to globally impaired transcriptional output, underscoring its non-redundant role.

Given its central position within the Mediator, MED14 has attracted interest in the context of developmental regulation, cell differentiation, and disease states including cancer, where transcriptional dysregulation is a common feature.

Protein Specifications and Quality Considerations

Recombinant Human MED14 Protein (SKU: rp366336) is produced using recombinant expression systems to deliver a research-grade protein suitable for biochemical and cell-free assays. Researchers should consult the official product datasheet for precise information on the following parameters, as these may be updated by the manufacturer:

• Expression System: Confirm whether the protein is expressed in a prokaryotic (e.g., E. coli) or eukaryotic (e.g., baculovirus/insect cell, HEK293) system, as this affects post-translational modification status.
• Purity: Recombinant proteins of research grade are typically ≥85% pure as assessed by SDS-PAGE; verify the exact purity specification on the datasheet.
• Tag Information: Many recombinant Mediator subunits are expressed with an affinity tag (e.g., His-tag, GST) to facilitate purification; confirm tag identity and position.
• Formulation and Buffer: The buffer composition, presence of stabilizers (e.g., glycerol, BSA), and protein concentration should be verified on the datasheet before experimental use.
• Endotoxin Level: For cell-based applications, verify endotoxin specifications to avoid confounding results.

Always centrifuge the vial briefly upon receipt and perform a small-scale pilot experiment to determine optimal working concentration for your specific assay format.

Recommended Handling and Storage Protocols

Proper handling of Recombinant Human MED14 Protein is critical to maintaining activity and reproducibility. The following general guidelines apply to recombinant proteins of this class; always cross-reference with the product-specific datasheet:

1. Upon Receipt: Inspect the packaging for signs of thawing. If the product arrives on dry ice and appears intact, proceed with aliquoting immediately to minimize freeze-thaw cycles.
2. Aliquoting: Prepare single-use aliquots at a volume appropriate for your experimental needs. This prevents repeated freeze-thaw cycles that can lead to protein aggregation and loss of activity.
3. Short-Term Storage: If the protein will be used within 1–2 weeks, store at 4°C in its supplied buffer. Verify this window on the datasheet.
4. Long-Term Storage: For extended storage, freeze aliquots at -80°C. Adding a carrier protein (e.g., 0.1% BSA) may improve stability; confirm compatibility with your downstream assay.
5. Avoid: Repeated freeze-thaw cycles, storage at -20°C for prolonged periods, and exposure to detergents or denaturing conditions unless specifically required by the protocol.
6. Working Concentration: Optimize empirically. Typical in vitro transcription or pull-down assays may use nanomolar to micromolar concentrations; exact values depend on assay format and must be determined experimentally.

Always keep the protein on ice during experimental setup and return unused portions to storage promptly.

Research Applications of MED14 Protein

Recombinant Human MED14 Protein supports a broad range of experimental approaches in transcription biology and related fields:

• In Vitro Transcription Reconstitution: MED14 can be incorporated into reconstituted Mediator sub-complexes or full Mediator assemblies to study the biochemical requirements for coactivator-dependent transcription activation in a defined, cell-free system.
• Protein–Protein Interaction Studies: MED14 interacts with multiple Mediator subunits as well as sequence-specific transcription factors. Pull-down assays, co-immunoprecipitation (co-IP), surface plasmon resonance (SPR), and yeast two-hybrid experiments can map these interactions and identify novel binding partners.
• Structural Biology: As a scaffold subunit, MED14 is relevant for cryo-electron microscopy (cryo-EM) and X-ray crystallography studies aimed at resolving Mediator architecture.
• Enzyme-Linked Immunosorbent Assay (ELISA) Standards: Recombinant MED14 may serve as a standard or positive control in immunoassay development for quantifying endogenous MED14 levels.
• Drug Discovery and Target Validation: Given MED14's role in oncogenic transcriptional programs, it represents a potential target for small-molecule inhibitor screening assays.
• Antibody Validation: Recombinant MED14 serves as an antigen for validating anti-MED14 antibodies used in Western blotting, immunoprecipitation, and immunofluorescence.

Troubleshooting and Best Practices

Researchers working with Recombinant Human MED14 Protein may encounter challenges common to large scaffold proteins. The following troubleshooting guidance is based on general best practices for recombinant protein handling:

• Low or No Activity: Verify that the protein has not undergone excessive freeze-thaw cycles. Check buffer compatibility with your assay system. Confirm that the working concentration is within the optimal range by titration.
• Protein Aggregation: Large scaffold proteins such as MED14 can be prone to aggregation. Centrifuge samples at 10,000–14,000 × g for 5–10 minutes at 4°C before use to remove aggregates. Consider adding mild detergent (e.g., 0.01% Tween-20) or mild reducing agent (e.g., 1 mM DTT) if compatible with the assay.
• Non-Specific Bands on Western Blot: Use appropriate blocking conditions (5% non-fat milk or BSA in TBST). Optimize antibody dilution and incubation conditions using recombinant MED14 as a positive control.
• Inconsistent Results Between Lots: Always record the lot number and check the certificate of analysis (CoA) for each lot. Run a standard curve or reference sample in parallel to normalize across experiments.
• Contamination Concerns: If using in cell-based assays, verify endotoxin levels via Limulus amebocyte lysate (LAL) test data provided in the CoA.

For application-specific troubleshooting beyond the scope of this guide, contact Aladdin Scientific technical support with your lot number and experimental details.

Frequently asked questions

What is the biological role of MED14 in transcription?

MED14 is a core scaffold subunit of the Mediator complex, a conserved multi-protein coactivator required for RNA polymerase II-dependent transcription. It stabilizes the architecture of the Mediator complex and facilitates communication between gene-specific transcription factors and the basal transcription machinery, thereby enabling robust transcriptional activation of target genes.

What applications is Recombinant Human MED14 Protein suitable for?

Recombinant Human MED14 Protein (SKU: rp366336) is suitable for in vitro transcription reconstitution assays, protein–protein interaction studies (pull-down, co-IP, SPR), structural biology investigations, antibody validation, ELISA standard development, and small-molecule inhibitor screening related to transcription coactivator biology.

How should Recombinant Human MED14 Protein be stored to maintain activity?

For long-term storage, aliquot the protein and freeze at -80°C to avoid repeated freeze-thaw cycles, which can cause aggregation and loss of activity. For short-term use within 1–2 weeks, storage at 4°C in the supplied buffer may be acceptable. Always verify the recommended storage conditions on the product datasheet, as specifications may vary by lot and formulation.

What expression system is used for Recombinant Human MED14 Protein?

The specific expression system used for rp366336 should be confirmed on the official product datasheet, as this information directly affects the protein's post-translational modification profile and suitability for specific applications. Common systems for large recombinant proteins include E. coli, baculovirus/insect cells, and mammalian cell lines such as HEK293.

How can I confirm the identity and purity of the MED14 protein I receive?

Each lot of Recombinant Human MED14 Protein is accompanied by a Certificate of Analysis (CoA) detailing purity (typically assessed by SDS-PAGE), protein concentration, and quality control test results. You can also validate protein identity using an anti-MED14 antibody on a Western blot, using the recombinant protein itself as a positive control.

References

1. Allen BL, Taatjes DJ. The Mediator complex: a central integrator of transcription. Nat Rev Mol Cell Biol. 2015;16(3):155-166. doi:10.1038/nrm3951
2. Tsai KL, Sato S, Tomomori-Sato C, et al. A conserved Mediator-CDK8 kinase module association regulates Mediator-RNA polymerase II interaction. Nat Struct Mol Biol. 2013;20(5):611-619. doi:10.1038/nsmb.2549
3. Cevher MA, Shi Y, Li D, et al. Reconstitution of active human core Mediator complex reveals a critical role of the MED14 subunit. Nat Struct Mol Biol. 2014;21(12):1028-1034. doi:10.1038/nsmb.2914

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