Novus Biologicals Blog

Archive for March, 2010

Mutant p53 Disrupts ASK-1 Induced MAPK Pathways

Wednesday, March 10th, 2010

MAPK (mitogen-activated protein kinase) antibodies are widely used in cellular research to study these processes, in both healthy and cancerous cells. For example, p38 is a pro-apoptotic factor, and c-Jun NH2-terminal kinase (JNK) regulates cellular longevity and stress resistance. Together they form the JNK/p38 signaling pathway, which is controlled by at least five MAPK cascades.

ASK1, also known as MAPKKK5 and MEKK5, is an apoptosis-regulating kinase which phosphorylates and stabilizes the Daxx protein. The two regulate each other via a positive feedback loop, i.e. higher Daxx levels lead to greater production of ASK1. ASK1 regulates cellular stress, for example that following activation of tumor necrosis factor alpha (TNFα). It is necessary for the sustained activation of JNK.

It has been shown that cancer treatment with TNFα leads to ASK1 activation and accumulation of Daxx. The p53 transcription factor is associated with this pathway, but is easily mutated, and in its mutant form can bind to Daxx. This inhibits the activation of ASK1 and therefore blocks the ASK1 phosphorylation of Daxx. In studies using mutant p53 and Daxx antibody in cancer cells, it was shown that when TM p53 was depleted, the level of Daxx increased and the apoptotic effect of TNFα was restored.

Western Blot: p53 Antibody

Western Blot: p53 Antibody

This shows that amplification of the JNK/p38 signaling pathway is important in regulating the cellular response to drug-induced apoptosis. Furthermore, the disruption of this pathway by Tumorigenic mutant p53 can lead to cell stress and tumor development.

The MAPK immunoglobulins that we at Novus Biologicals have in our antibody catalog cover a large number of signaling pathways.

Novus Biologicals offers many p53 reagents for your research needs including:

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.

Immunohistochemistry: cIAP2 Antibody

Immunohistochemistry: cIAP2 Antibody

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.

Novus Biologicals offers many cIAP2 reagents for your research needs including:

Weekly Update On Happenings In The Novus Antibody Lab

Thursday, March 4th, 2010

The antibody lab technicians here at Novus Biologicals are constantly busy conducting purifications, conjugations and QC analysis in order to maintain our antibody catalog of over 100,000 products. Just this past week, the lab team conjugated numerous antibodies and tested several newly purified antibody lots.

A few recent examples of antibody conjugations include conjugating the rabbit polyclonal anti-PINK1 antibody (catalog number NB100-493) and the mouse monoclonal anti-HSD3B1 antibody (clone FDO66Q) (catalog number NB110-78644) to HRP. Horseradish peroxidase (HRP) is the most commonly used enzyme label for antibodies. Its stability, small size and broad specificity make it an ideal label for immunoblotting and immunocytochemistry. The Novus antibody lab also conjugated a large number antibodies to DyLight dyes last week, including rat monoclonal anti-CD105 antibody (clone MJ7/18) (catalog number NB100-77666) and rabbit polyclonal anti-Carbonic Anhydrase IX antibody (catalog number NB100-417).

We at Novus Biologicals adhere to a strict QC analysis process in order to assure our antibodies are validated for the appropriate research applications. Our laboratory technicians conducted numerous Western blots last week. New lots of two GRP78 antibodies (catalog numbers NBP1-06277 and NBP1-06274) were tested on HeLa whole cell lysates where specific bands at 72kDa were visualized for both antibodies. One of our newest antibodies, a LOX Propeptide antibody (catalog number NBP1-30327), was tested in Jurkat lysate and picked up the glycosylated propeptide as well as the proenzyme form. Also tested this week was a SOX2 antibody (catalog number NB110-37235). The new SOX2 antibody lot was tested on mouse brain lysate using a 4-12% MOPS gel. This Western blot analysis produced a clear band at 39kDa.

Check the Novus Biologicals Antibody Blog for frequent updates on our lab and antibody catalog, and to learn more about new antibody developments and recent scientific findings.