Product Name: LKB1 (STK11)-pS428
Product Number: AB-PK683
Size: 25 µg      Price:89.00
      $US
Target Full Name: Serine/threonine-protein kinase 11

Target Alias: AMPKK; KPM; PJS; Renal carcinoma antigen NY-REN-19; STK11; NY-REN-19 antigen; ENSG00000118046

Product Type Specific: Protein kinase phosphosite-specific antibody

Antibody Code: PK683

Antibody Target Type: Phosphosite-specific

Antibody Phosphosite: S428

Protein UniProt: Q15831

Protein SigNET: Q15831

Antibody Type: Polyclonal

Antibody Host Species: Rabbit

Antibody Immunogen Source: Human LKB1 (STK11) sequence peptide Cat. No.: PE-04ANK95

Antibody Immunogen Sequence: RRL(pS)ACK(bA)C

Antibody Immunogen Description: Corresponds to amino acid residues R425 to K431; In the C-terminus of the kinase

Production Method: The immunizing peptide was produced by solid phase synthesis on a multipep peptide synthesizer and purified by reverse-phase hplc chromatography. Purity was assessed by analytical hplc and the amino acid sequence confirmed by mass spectrometry analysis. This peptide was coupled to KLH prior to immunization into rabbits. New Zealand White rabbits were subcutaneously injected with KLH-coupled immunizing peptide every 4 weeks for 4 months. The sera from these animals was applied onto an agarose column to which the immunogen peptide was thio-linked. Antibody was eluted from the column with 0.1 M glycine, pH 2.5. Subsequently, the antibody solution was neutralized to pH 7.0 with saturated Tris.This antibody was also subject to negative purification over phosphotyrosine-agarose.

Antibody Modification: Unconjugated. Contact KInexus if you are interest in having the antibody biotinylated or coupled with fluorescent dyes.

Antibody Concentration: 1 mg/ml

Storage Buffer: Phosphate buffered saline pH 7.4, 0.05% Thimerasol

Storage Conditions: For long term storage, keep frozen at -40°C or lower. Stock solution can be kept at +4°C for more than 3 months. Avoid repeated freeze-thaw cycles.

Product Use: Western blotting | Antibody microarray

Antibody Dilution Recommended: 2 µg/ml for immunoblotting

Antibody Potency: Medium immunoreactivity with immunogen peptide on dot blots.

Antibody Species Reactivity: Human

Antibody Positive Control: The observed molecular mass of the processed target protein on SDS-PAGE gels is reported to be around 50-60 kDa.

Antibody Specificity: High-very high

Antibody Cross Reactivity: No significant cross-reactive proteins detected in A431, HepG2, Jurkat and MCF7 cells.

Related Product 1: LKB1 (STK11)-pS428 blocking peptide

Related Product 2: LKB1 (STK11) pan-specific antibody (Cat. No.: AB-NK227-1)

Related Product 3: LKB1-1 pan-specific antibody (Cat. No.: AB-NK227-2)

Related Product 4: LKB1 (STK11) pan-specific antibody (Cat. No.: AB-NK227-2P)

Related Product 5: LKB1-2 pan-specific antibody (Cat. No.: AB-NK227-3)

Related Product 6: LKB1-3 pan-specific antibody (Cat. No.: AB-NK227-4)

Related Product 7: LKB1 (STK11)-pS31 phosphosite-specific antibody (Cat. No.: AB-PK682)
Related Product 8: LKBSubtide - LKB1 (STK11) protein kinase substrate peptide

Scientific Background: LKB1 (STK11) is a protein-serine/threonine kinase of the CAMK group and CAMKL family. LKB1 has important roles in the regulation of cell metabolism, cell polarity, apoptosis, and the response to DNA damage. LKB1 promotes recruitment of p53/TP53 to the CDKN1A/WAF1 promoter to activate transcription. in addition, LKB1 regulates p53/TP53-dependent apotosis pathways. The LKB1 protein is found in the nucleus and cytoplasm of cells and translocates to the mitochondria during apoptosis. LKB1 is activated by binding of a complex consisting of CAB39 and STRAD or CAB39 and ALS2CR2. Phosphorylation at S307 induces interaction with AMPK1, STLK5 and exportin 1. Phosphorylation at S428 increases phosphotransferase activity. Phosphorylation at T336 inhibits LKB1. It displays tumour suppressor activity that functions in the regulation of AMP-activated protein kinase (AMPK) family members through phosphorylation of their activation T-loop. LKB1 appears to be a tumour suppressor protein (TSP). Cancer-related mutations in human tumours point to a loss of function of the protein kinase. In particularly, cancer-associated mutations are found in the substrate recognition domain of the protein or result in protein truncation. Significantly reduced LKB1 expression has been observed in benign intestinal polyps, which correlated with reduced apoptosis, which may potentially contribute to the development of malignant intestinal tumours. Additionally, LKB1 protein in tumour cells is restricted to the nucleus, compared to the normal distribution of the protein in both the nucleus and cytoplasm. The introduction of LKB1 protein into LKB1-deficient cancer cell lines results in G1 phase cell cycle arrest. This effect is still seen for LKB1 proteins that lack nuclear localization signals, indicating that the tumour suppressive effects of the kinase are mediated in the cytoplasm. The proposed mechanism of LKB1-mediated cell cycle arrest is a p53-dependent induction of p21. Analysis of gene expression in human lung cancer cell lines and mouse lung tumours revealed that repression of LKB1 results in the activation of various metastasis-promoting genes, such as NEDD9, VEGFC, and CD24.
Figure 1. Epitope mapping of LKB1-pS428 antibody with similar phosphopeptides on dot blots.


Figure 2. Identification of phosphosites related to LKB1-pS428.