Recombinant TRIM28 (624-811) protein

Aliases: KAP1; TF1B; RNF96; TIF1B; PPP1R157
Catalog No: 31441 Format: 100 µg $400 Buy
Catalog No: 31841 Format: 1 mg $3,000 Buy

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Expressed In: E. coli Protein Species: Human

Contents

A representative Technical Data Sheet (TDS) is provided here. Please refer to the lot-specific TDS you will receive with your order for the lot-specific buffer contents and protein concentration.

Background

Tripartite motif-containing 28 (TRIM28) protein, also known as transcriptional intermediary factor 1β (TIF1β) and KAP1 (Krüppel-associated protein), is a member of the transcriptional intermediary factor 1 (TIF1) family that control transcription and chromatin remodeling through their interaction with transcription factors. The family includes enhances transcriptional repression by coordinating the increase in TRIM24 (TIF1α), TRIM28 (TIF1β) and TRIM33 (TIF1γ) that share a characteristic domain structure comprised of multiple histone-binding domains, an N-terminal TRIM region (containing a RING domain, B box type 1 and type 2 domains, and a coiled-coil region), and a C-terminal bromodomain and PHD finger. Bromodomains function as ‘readers’ of epigenetic histone marks and regulate chromatin structure and gene expression by linking associated proteins to the recognized acetylated nucleosomal targets. TRIM28 has been shown to function as a nuclear corepressor for KRAB domain-containing zinc finger proteins (KRAB-ZFPs). It also mediates gene silencing by recruiting CHD3, a subunit of the nucleosome remodeling and deacetylation (NuRD) complex, and SETDB1 (which specifically methylates histone H3 at lysine 9) to the promoter regions of KRAB target genes. TRIM28 enhances transcriptional repression by coordinating the increase in H3K9 methylation, the decrease in H3K9 and H3K14 acetylation, respectively, and the disposition of HP1 proteins to silence gene expression. It also acts as a corepressor for ErbB-4. TRIM28 inhibits E2F1 activity by stimulating E2F1-HDAC1 complex formation and inhibiting E2F1 acetylation and may serve as a partial backup to prevent E2F1-mediated apoptosis in the absence of pRb. TRIM28 has E3 SUMO-protein ligase activity toward itself via its PHD-type zinc finger. TRIM28 also specifically SUMOylates IRF7, inhibiting its transactivation activity, and ubiquitinates p53 leading to its proteosomal degradation.

Application Notes

Recombinant TRIM28 (624-811) is suitable for use in binding assays, inhibitor screening, and selectivity profiling.

Protein Details

The peptide corresponding to amino acids 624-811 that contains the bromodomain sequences of TRIM28 (accession number NP_005753.1) was expressed in E. coli and contains an N-terminal His-Tag and C-terminal FLAG-Tag with an observed molecular weight of 26.18 kDa. The recombinant protein is >87% pure by SDS-PAGE.

 

Recombinant TRIM28 (624-811) protein gel.
TRIM28 (624-811) protein was run on an SDS-PAGE gel and stained with Coomassie Blue.

Recombinant TRIM28 (624-811) activity assay.
3.3 µM histone peptide H4K5/8/12/16 (4ac) was incubated with TRIM28 (624-811) in reaction buffer including 50 mM HEPES-NaOH pH 7.0, 0.1% BSA for 1 hour at room temperature. Anti-FLAG antibody was used to detect reaction products.

Storage

Recombinant proteins in solution are temperature sensitive and must be stored at -80°C to prevent degradation. Avoid repeated freeze/thaw cycles and keep on ice when not in storage.

Guarantee

This product is guaranteed for 6 months from date of receipt.

This product is for research use only and is not for use in diagnostic procedures.