Anti-Human/mouse GRP78 [Clone N88] – Purified in vivo PLATINUM™ Functional Grade

Recombinant protein corresponding to human GRP78.

This monoclonal antibody is aseptically packaged and formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.2 - 7.4 with no carrier protein, potassium, calcium or preservatives added. Due to inherent biochemical properties of antibodies, certain products may be prone to precipitation over time. Precipitation may be removed by aseptic centrifugation and/or filtration.

Liquid

Functional grade preclinical antibodies are manufactured in an animal free facility using in vitro cell culture techniques and are purified by a multi-step process including the use of protein A or G to assure extremely low levels of endotoxins, leachable protein A or aggregates.

To protect mouse colonies from infection by pathogens and to assure that experimental preclinical data is not affected by such pathogens, all of Leinco’s Purified Functional PLATINUM ™ antibodies are tested and guaranteed to be negative for all pathogens in the IDEXX IMPACT I Mouse Profile.

Functional grade preclinical antibodies may be stored sterile as received at 2-8°C for up to one month. For longer term storage, aseptically aliquot in working volumes without diluting and store at ≤ -70°C. Avoid Repeated Freeze Thaw Cycles.

Research Use Only

2 – 8° C Wet Ice

Activity is directed against the 78 kDa glucose-regulated protein (GRP78), also known as Binding Immunoglobulin Protein (BiP) or HSPA5^1,2. Clone N88 recognizes a highly conserved epitope on the GRP78 protein, enabling robust cross-reactivity between human, mouse, and rat species¹. Human cancer patients often develop PI3K-agonist autoantibodies that recognize this epitope, mimicked by the synthetic peptide CNVSDKSC (Pep1); the GRP78-binding capacity of clone N88 can be inhibited by Pep1. Clone N88 also stimulates Akt phosphorylation¹.

GRP78 is a member of the Heat Shock Protein 70 (HSP70) family and acts as a master molecular chaperone in the ER⁴. It plays a dual role: it facilitates the proper folding and assembly of nascent proteins while simultaneously acting as the primary sensor for ER stress, regulating the Unfolded Protein Response (UPR)^4,5.

Under normal physiological conditions, GRP78 binds to the luminal domains of three ER stress sensors: PERK, IRE1, and ATF6, keeping them in an inactive state^4,6. Upon the accumulation of unfolded proteins, GRP78 dissociates from these sensors to provide chaperoning assistance, thereby triggering the UPR signaling cascade to restore cellular proteostasis⁴. Clone N88 is a standard reagent for monitoring ER stress induction in experimental models of neurodegeneration, diabetes, and cardiovascular disease. Beyond the ER, surface-expressed GRP78 (sGRP78) acts as a signaling receptor that promotes tumor cell proliferation, survival, and resistance to chemotherapy^3,6. Because GRP78 is essential for the survival of malignant cells under hypoxic and nutrient-deprived conditions, clone N88 is frequently used to investigate GRP78 as a potential biomarker and therapeutic target in oncology.

GRP78 is traditionally localized to the lumen of the endoplasmic reticulum (ER) in all nucleated cells, but is significantly upregulated and translocated to the cell surface in various cancer cells, stressed tissues, and during viral infections^2,3.

Interacts with unfolded proteins, PERK, IRE1, ATF6

P11021
P20029

1. de Ridder GG, et al. A murine monoclonal antibody directed against the carboxyl-terminal domain of GRP78 suppresses melanoma growth in mice. Mel Res. 22(3):225-235. 2012.
2. Lee AS. The glucose-regulated proteins: stress induction and clinical applications. Trends Biochem Sci. 26(8):504-510. 2001.
3. Gonzalez-Gronow M, et al. GRP78: a multifunctional receptor on the cell surface. Antioxid Redox Signal. 11(9):2299-2306. 2009.
4. Hendershot LM. The ER chaperone BiP is a master regulator of ER function. Mt Sinai J Med. 71(5):289-297. 2004.
5. Lee AS. GRP78 protein expression: role in oncology and development of therapeutic strategies. Cancer Res. 67(8):3496-3499. 2007.
6. Pfaffenbach HG, Lee AS. The critical role of GRP78 in physiologic and pathologic stress. Curr Opin Cell Biol. 23(2):150-156. 2011.