Posts Tagged ‘Survivin antibody’

Survivin antibody assays using Sandwich ELISA kits

Thursday, September 22nd, 2011

The Survivin antibody is widely used in apoptosis studies, and as a cellular marker. Today, biochemists have a wide range of Survivin antibody products to choose from, suitable for use in Western Blot, Chromatin Immunoprecipitation (ChIP), Immunofluorescence and similar assays.

ELISA (Enzyme-linked immunosorbent assay) is a popular tool in Survivin antibody research. In simple terms, ELISA involves binding of an antigen to an enzyme-linked antibody, which must be highly specific. Various formats of this basic technique have been developed, the most powerful of which is the Sandwich ELISA assay. Sandwich ELISA is dependent upon antigens with at least two binding sites, as it uses both a capture and a detection antibody, between which the sample is “sandwiched.” This has several benefits over standard ELISA, including increased sensitivity and the fact samples do not need to be purified prior to analysis.

The one disadvantage with sandwich ELISA is that antibody optimization can be difficult. It’s essential each antibody reacts with a specific epitope on the target protein and does not cross-react with its partner, and so only products specifically tested for sandwich ELISA should be used. We at Novus Biologicals have achieved this with our sandwich ELISA kits, such as our human Survivin antibody ELISA kit.

The capture antibody of this quality assured kit is polyclonal human Survivin antibody, coated onto the 96-well strip plates, which are provided. Having added human sera or test standards to these plates, a biotinylated detection antibody is added, completing the sandwich. Survivin detection is achieved via an ABC-complex enzyme, which binds to the detection antibody. A peroxidase substrate induces a quantitative coloured reaction. This kit is ideal when Survivin antibody testing of human tissue samples is required.

Survivin Acetylation: Affecting Apoptosis and Cancer

Thursday, June 2nd, 2011

Survivin (BRIC5) is an inhibitor of apoptosis that also promotes cellular adaptation under stressful conditions and helps to regulate cell division. Recently, a group of researchers led by Dr. H Wang of Brown University* found that Survivin is acetylated at lysine residue 129, thereby affecting its subsequent subcellular localization. Specifically, acetylation promotes Survivin to homodimerize and localize in the nucleus, whereas deacetylation causes heterodimerization with CRM1 and export from the nucleus.

Additionally, the authors found that acetylation causes the nuclear-localized Survivin to bind to STAT3 and inhibit the activation of STAT3 target oncogenes. This was confirmed using a mutated 129K nucleotide to prevent survivin nuclear localization, thereby allowing STAT3 transactivation to proceed.

These results demonstrate that Survivin acetylation affects both the protein localization and its interaction with the tumor activator STAT3. Therefore, therapies controlling Survivin acetylation will potentially prove useful for treating STAT3-dependent tumors.

Novus Biologicals recently released the acetyl-specific-Survivin [acetyl K129] antibody used in this study. The antibody has been validated for Western blot and immunostaining human samples and will be useful for researchers studying survivin apoptosis pathways and STAT3 activated cancers.

*Wang H, Holloway MP, Ma L, et al. Acetylation directs survivin nuclear localization to repress STAT3 oncogenic activity. J Biol Chem. 2010 Nov 12;285(46):36129-37. [PMID: 20826784]

New cIAP Antibodies Pave The Way In Human Cancer Research

Tuesday, March 9th, 2010

Apoptosis inhibitors are a well studied group of proteins that have been implicated in the formation of several types of human tumor. The most commonly studied IAP (inhibitor of apoptosis protein) is the Survivin antibody. However, our apoptosis antibody catalog at Novus Biologicals is constantly being updated to reflect the growing list of newer proteins. cIAP1 and cIAP2 antibodies are among the more recent of our anti-apoptosis products.

All IAP proteins are characterized by their ability to suppress cell death via their BIR (baculoviral IAP repeat), a novel domain consisting of around 70 amino acids. Some have an additional CARD and/or RING domains. They prevent apoptosis by inhibition of TNF and other pro-apoptosis proteins. This is done by the binding and inactivation of various caspases (cell death proteases).

The cIAP protein mediates TRAF2 ubiquitination following the receptor binding of TNF-alpha. It has two isoforms, structurally similar to XIAP. Each has three BIR motifs which bind to caspase-3 and caspase-7. cIAP 1/2 form a heteromeric complex which is then recruited to the death receptor TNF-R2 (tumor necrosis factor receptor 2) via the TNF receptor associated factors 1 and 2 (TRAF1 and TRAF2).

cIAP is inhibited by HtrA2 (also called Omi) which acts by catalytic cleaving of the protein. Smac/DIABLO is another negative regulator which works by enhancing the autoubiquitination action of cIAP.

The cIAP1 and 2 immunoglobulins are recent additions to our antibody database at Novus Biologicals, and have been used in studies into human cancers. In January 2010, cIAP2 antibodies were used in a study showing retinoic acid having a possible protective role in the battle against breast cancer.