Mesothelin Antibody (Rabbit mAb) [G1K4]

Application: Reactivity: Human

Usage Information

Dilution
WB1:1000 IP1:30 IHC1:500 FCM1:50

Application
WB, IP, IHC, FCM

Reactivity
Human

Source
Rabbit Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW Observed MW
68 kDa 40 kDa, 69 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight. Post-translational modifications(e.g., phosphorylation, glycosylation); Splice variants and isoforms; Relative charge; Multimerization.

Positive Control	Human ovary cancer tissue; Human ovarian adenocarcinoma tissue; Human mesothelioma tissue; HeLa cells; OVCAR-3 cells; HeLa cells
Negative Control	A549 cells; PC-3 cells

Datasheet & SDS

Biological Description

Specificity
Mesothelin Antibody (Rabbit mAb) [G1K4] detects endogenous levels of total Mesothelin protein.

Clone
G1K4

Synonym(s)
MPF, MSLN, Mesothelin, CAK1 antigen, Pre-pro-megakaryocyte-potentiating factor

Background
Mesothelin is synthesized as a precursor protein that undergoes signal peptide removal in the endoplasmic reticulum, followed by proteolytic cleavage at a furin site that generates two distinct products: a smaller secreted fragment known as megakaryocyte-potentiating factor, which promotes megakaryocyte colony formation, and a larger glycosylphosphatidylinositol-anchored mature mesothelin that remains tethered to the outer leaflet of the plasma membrane, expressed natively on the mesothelial cells lining the peritoneal, pleural, and pericardial cavities. The GPI-anchored mature form carries the receptor-binding function of the protein, and systematic truncation and alanine-scanning mutagenesis localize the binding site for its principal ligand, the mucin CA125/MUC16, to a specific, conformation-dependent region of the mesothelin ectodomain; a single-chain monoclonal antibody directed against this identified CA125-binding domain blocks the mesothelin-CA125 interaction on cancer cells and correspondingly inhibits cancer cell adhesion in functional assays, confirming that this mapped region is both necessary and sufficient for productive receptor engagement. Through this defined interface, membrane-bound mesothelin on mesothelial cells captures CA125/MUC16 displayed on the surface of ovarian carcinoma cells, and this heterotypic adhesion event is directly blocked by anti-mesothelin antibody, establishing mesothelin-CA125 binding as a specific route through which ovarian cancer cells attach to the peritoneal mesothelial lining as an initiating step in peritoneal metastasis. Beyond this adhesive function, secreted mesothelin binding to surface-expressed MUC16 activates an intracellular signaling cascade in pancreatic cancer cells: the interaction selectively induces expression of matrix metalloproteinase-7 through a p38 MAPK-dependent pathway, and either depleting MMP-7 or pharmacologically inhibiting p38 activity abolishes the enhanced motility and invasion that mesothelin-MUC16 engagement otherwise produces, directly linking receptor engagement to a defined downstream proteolytic effector required for the invasive phenotype. Mesothelin and CA125/MUC16 are frequently co-overexpressed at the invading edges of tumor tissue in ovarian and pancreatic cancer, and this co-expression pattern correlates with reduced patient survival, positioning the mesothelin-MUC16 interaction as functionally active in tumor progression rather than merely a correlative biomarker association.

Background

Mesothelin is synthesized as a precursor protein that undergoes signal peptide removal in the endoplasmic reticulum, followed by proteolytic cleavage at a furin site that generates two distinct products: a smaller secreted fragment known as megakaryocyte-potentiating factor, which promotes megakaryocyte colony formation, and a larger glycosylphosphatidylinositol-anchored mature mesothelin that remains tethered to the outer leaflet of the plasma membrane, expressed natively on the mesothelial cells lining the peritoneal, pleural, and pericardial cavities. The GPI-anchored mature form carries the receptor-binding function of the protein, and systematic truncation and alanine-scanning mutagenesis localize the binding site for its principal ligand, the mucin CA125/MUC16, to a specific, conformation-dependent region of the mesothelin ectodomain; a single-chain monoclonal antibody directed against this identified CA125-binding domain blocks the mesothelin-CA125 interaction on cancer cells and correspondingly inhibits cancer cell adhesion in functional assays, confirming that this mapped region is both necessary and sufficient for productive receptor engagement. Through this defined interface, membrane-bound mesothelin on mesothelial cells captures CA125/MUC16 displayed on the surface of ovarian carcinoma cells, and this heterotypic adhesion event is directly blocked by anti-mesothelin antibody, establishing mesothelin-CA125 binding as a specific route through which ovarian cancer cells attach to the peritoneal mesothelial lining as an initiating step in peritoneal metastasis. Beyond this adhesive function, secreted mesothelin binding to surface-expressed MUC16 activates an intracellular signaling cascade in pancreatic cancer cells: the interaction selectively induces expression of matrix metalloproteinase-7 through a p38 MAPK-dependent pathway, and either depleting MMP-7 or pharmacologically inhibiting p38 activity abolishes the enhanced motility and invasion that mesothelin-MUC16 engagement otherwise produces, directly linking receptor engagement to a defined downstream proteolytic effector required for the invasive phenotype. Mesothelin and CA125/MUC16 are frequently co-overexpressed at the invading edges of tumor tissue in ovarian and pancreatic cancer, and this co-expression pattern correlates with reduced patient survival, positioning the mesothelin-MUC16 interaction as functionally active in tumor progression rather than merely a correlative biomarker association.

References
https://pubmed.ncbi.nlm.nih.gov/23694968/ https://pubmed.ncbi.nlm.nih.gov/14676194/

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%