Recombinant Human CALU protein(Met1-Arg311), His-tagged

• Cat.No.: CALU-8590H
• Product Overview: Recombinant Human CALU (O43852-1) (Met1-Arg311) was expressed in HEK293 with a polyhistidine tag at the C-terminus.

Specification

• Species: Human
• Source: HEK293
• Tag: His
• Protein Length: 1-311 a.a.
• Form: Lyophilized from sterile PBS, pH 7.4. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween80 are added as protectants before lyophilization.
• Molecular Mass: The recombinant human CALU consists of 303 amino acids and predicts a molecular mass of 35.9 KDa. It migrates as an approximately 46-52 KDa band in SDS-PAGE under reducing conditions.
• Endotoxin: < 1.0 EU per μg of the protein as determined by the LAL method
• Purity: > 90 % as determined by SDS-PAGE
• Storage: Samples are stable for up to twelve months from date of receipt at -20°C to -80°C. Store it under sterile conditions at -20°C to -80°C. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.
• Reconstitution: It is recommended that sterile water be added to the vial to prepare a stock solution of 0.2 ug/ul. Centrifuge the vial at 4°C before opening to recover the entire contents.

Gene Information

• Gene Name: CALU calumenin [ Homo sapiens ]
• Official Symbol: CALU
• Synonyms: CALU; calumenin; crocalbin; IEF SSP 9302; crocalbin-like protein; multiple EF-hand protein; FLJ90608
• Gene ID: 813
• mRNA Refseq: NM_001130674
• Protein Refseq: NP_001124146
• MIM: 603420
• UniProt ID: O43852

Case Study

Case 1: Philippe R, et al. Cell Calcium. 2017

Cystic Fibrosis (CF) is a leading genetic killer in Caucasian communities, stemming from mistakes in the CFTR gene, which controls a chloride channel. The most frequent defect, F508del-CFTR, causes the protein to fold wrongly, trapping it in the ER and causing a calcium imbalance. Our study found that Calumenin (CALU), a protein that binds calcium, plays a crucial role in keeping calcium balance in both normal and mutated cells. It adjusts SERCA pump activity without major changes to ER calcium levels. Interestingly, reducing Calumenin in CF cells helps restore some CFTR activity, suggesting that Calumenin might aid CFTR processing. This points to the possibility of using Calumenin adjustments as a treatment approach for the F508del-CFTR mutation.

Fig1. Western blot analysis of Calumenin expression in 16HBE and CFBE cells.

Fig2. CFTR activity measured using SPQ fluorescence after Calumenin knockdown.

Case 2: Feng H, et al. Cell Death Dis. 2013

Filopodia are tiny, actin-rich cell extensions playing a key role in how cells move and how cancer spreads. A new player in this process is Calumenin-15 (Calu-15), one of 13 newly found variants from the Calumenin family. Calu-15 aids in creating filopodia and boosting cell movement by moving between the nucleus and cytoplasm, partnering with certain proteins. Its entrance into the nucleus relies on being phosphorylated at a specific site by CK2; disrupting this process halts its nuclear journey. Inside the nucleus, Calu-15 ramps up the production of GDF-15, linked to the TGF-β family, which in turn pushes filopodia formation. This reveals Calu-15's crucial role in cell migration through its influence on GDF-15 transcription.

Fig1. Immunoblottings (WB) of endogenous Calu-15 in the cytoplasmic and nuclear fraction from HeLa cells.

Fig2. HeLa cells transfected with Calu-15–2 × EGFP or 2 × EGFP were stained with Atto 565 phalloidin to show the localization and distribution of filamentous (F)-actin.

Application

Human CALU, short for Calumenin, is a calcium-binding player in the endoplasmic reticulum (ER), helping with protein folding and sorting. Scientists often turn to recombinant Human CALU (rhCALU) to understand its calcium-binding properties and how it might regulate processes like vitamin K-dependent carboxylation. Through various lab techniques like ELISA and Western blot, researchers study rhCALU to get a handle on its role in the molecular landscape.

In the industrial scene, rhCALU is produced for drug discovery efforts, especially where protein misfolding and calcium signaling go awry. By using expression systems like E. coli, often tagged with a His label for easier purification, rhCALU becomes a cornerstone for developing new treatments and diving deep into ER-related disorders. It's also key for making standardized research tools, ensuring experiments run smoothly and consistently.

Fig1. Proposed model outlining the role of calumenin in HPM-dependent differentiation of VSMC into osteoblast-like cells. (Eva Jover, 2015)