Archive for February, 2012
Monday, February 27th, 2012
Adiponectin (also called AdipoQ and Acrp30) is a circulating cytokine primarily expressed in adipose tissue. A complex protein with a number of physiological roles, adiponectin antibody experiments have revealed multiple forms of the protein in circulation, including trimers, multioligomers and cleavage fragments. We at Novus Biologicals stock an extensive range of adiponectin antibodies, as well as recombinant proteins and ELISA adiponectin antibody kits.
Adiponectin was first characterized in differentiating adipocyte cells of mice. Despite being the most dominant protein in human adipose tissue, lean people have the highest plasma circulating levels (0.01%). Obese humans display marked down-regulation of AdipoQ, associated with hyperinsulinemia and insulin resistance.
Adiponectin antibody research conducted since 1995 has revealed the protein to have a number of physiological functions, playing a central role in energy metabolism, vascular health and insulin regulation. It is also thought to have possible roles in apoptosis and the mediation of proinflammatory cytokines, such as TNF alpha. Interestingly, Acrp30 levels are around1000x lower in brain.
The discovery of the G-protein coupled adiponectin receptors AdipoR1/AdipoR2 have helped clarify the functions of AdipoQ. Using relevant antibodies, scientists have identified adiponectin receptors in a number of tissues, including muscle, brain and bone. These receptors have unique downstream signalling mechanisms and a very different structure to standard G-protein coupled receptors, varying in their ability to bind AdipoQ. T-cadherin is also thought to have a role.
Two critical signalling partners, APPL1 and APPL2, have been identified whose role is to transmit AdipoQ signals to downstream kinases such as p38, AKT and AMPK. Interestingly, adiponectin antibody studies suggest they may work in opposition, to mediate AdipoQ function in various cell types.
Tags: Adiponectin, Adiponectin antibody, Adiponectin Receptor 1, Adiponectin Receptor 1 antibody, Adiponectin Receptor 2, Adiponectin Receptor 2 antibody, Akt, Akt antibody, AMPK, AMPK antibody, TNF alpha, TNF alpha antibody
Posted in Antibodies, Antibody catalog, Antibody database, Antibody suppliers, Apoptosis, Diabetes, Inflammation, Lipid & Metabolism | No Comments »
Friday, February 24th, 2012
Platelet Endothelial Cell Adhesion Molecule 1 (PECAM1) is a single-pass membrane receptor also known as CD31 (cluster of differentiation 31.) CD31 is expressed at high levels at endothelial cell junctions, and therefore the CD31 antibody is widely used as an endothelial marker, one use being to measure the progression of angiogenesis following recurrence of tumors. Other CD31 antibody studies have suggested a possible use as a myeloid progenitor cell marker, and in the identification of different granular sarcoma subsets.
Novus Biologicals is constantly refining our CD31 antibody catalog to ensure customers have a wide range of reagents to choose from, covering as many assay applications as possible. In addition to standard monoclonals and polyclonals, our catalog also contains a variety of CD31 antibody reagents conjugated to various chromogenic and fluorochromic dyes. Each monoclonal product has a clone identifier in brackets. This identifies which cloned cell line the CD31 antibody was derived from (which may have been established for several years) and is an important factor as different clones can give different results, affecting continuity of research.
A perfect example of this is the CD31 antibody clone TLD-3A12, developed by K.C Williams, et al. in 1996 for rat CNS studies. Novus offers the TLD-3A12 antibody in unconjugated (NB100-64796), Biotin (NB100-63701) FITC (NB100-63703) and R-Phycoerythrin (NB100-63704) formats. However, studies have shown this clone partially blocks the proliferative response of antigen-specific CD4+ T cells when exposed to the antigen and cells expressing it, so for functional studies an alternative is recommended.
Please contact our technical support department (technical@novusbio.com) with any inquiries or for help selecting the best CD31/PECAM1 antibody for your experiment.
Tags: antibody conjugation, CD31, CD31/PECAM1, CD31/PECAM1 antibody, Conjugated antibody, Monoclonal antibody, PECAM1, Polyclonal antbody
Posted in Angiogenesis, Antibodies, Antibody catalog, Antibody database, Antibody suppliers, Cancer | No Comments »
Thursday, February 23rd, 2012
Novus Biologicals offers the widest selection of conjugated CD4 antibody products, with a database that’s continually expanding to take into account the latest developments. This includes CD4 antibodies conjugated to Dynomics and PE fluorescent dyes, for FACS analysis.
CD4 is a cluster of differentiation transmembrane protein belonging to the immunoglobulin superfamily (IgSF), a large group of proteins with functions in the recognition, adhesion and binding of cells. CD4 is widely expressed on T helper lymphocytes, and to a lesser degree on monocytes, macrophages, and dendritic cells.
Conjugated antibodies are those which are chemically bound to a dye; either chromatic (chromogen) or fluorescent (fluorochrome) to allow visual detection of the antigen for quantitative analysis. Conjugated CD4 antibodies are widely used as stem cell markers, in a variety of assays. Applications vary depending on the conjugate, but include immunoprecipitation (IP); immunohistochemistry (IHC); immunofluorescence; flow cytometry (FCM) analysis. FACS (fluorescence-activated cell sorting) is a specialized form of FCM, used in, for example, the sorting of stem cells for cloning.
Our conjugated CD4 antibodies include a number of fluorochrome-conjugated reagents, for example our Phycoerythrin (PE) antibodies, which activate and fluoresce (emit light) at specific wavelengths.
PE is a large protein derived from algae, and one of the most commonly used FACS dyes. The dye has a large absorption coefficient, and even though only one PE molecule is normally conjugated to each CD4 antibody, it is one of the brightest dyes in use today. It can be excited by common Argon laser tuned to 488 nm; although some users prefer a 533nm setting, which is more sensitive. It emits at around 570 nm.
Tags: antibody conjugation, CD4, CD4 antibody, Cluster of Differentiation, Conjugated antibody, Fluorescent dye, PE conjugated
Posted in Antibodies, Antibody catalog, Antibody database, Antibody suppliers, Support Products | No Comments »
Thursday, February 16th, 2012
The matrix metalloproteinases are zinc-dependent protease enzymes which interact with a range of ECM (extracellular matrix) proteins, and are activated by proteolytic cleavage. We at Novus Biologicals offer a wide range of top quality MMP reagents, including MMP3, MMP7, MMP9, MMP13 and MMP2 specific antibodies.
All the above proteins are known to play important roles in embryonic development, wound healing, angiogenesis, carcinogenesis, tumour invasion and apoptosis. Overexpression of MMP2 and MMP9 is associated with tumour migration, metastasis and aggressive, invasive cancers such as chondrosarcomas, malignant astrocytomas, melanomas and breast cancer. It is thought this occurs through degradation of the ECM proteins, primarily Collagen IV and Laminin 5, allowing migration of metastatic cells through the basement membrane, with enhanced tumour growth.
The heat shock protein HSP90 is uploaded at times of cellular stress, with increasing evidence to show that it acts as a molecular chaperone. A recent study by D. Stellas et al. [PMID: 20602761] suggested HSP90 could be a target for antibody therapy. The team used various monoclonal antibodies (mAbs) to probe the interaction of HSP90 isoforms with MMP2 and MMP9. They also examined the role of a new HSP90 mAb, called 4C5, in inhibiting metastasis and metastatic cell invasion, using a mouse model of human breast cancer.
The breast cancer cells secreted HSP90, which then interacted with MMP2 and MMP9 to activate them. MMP9/MMP2 antibody assays showed that while 4C5 antibodies did not restrict the release of inactive MMP2/MMP9 from cancer cells, their activation was blocked through disruption of the extracellular HSP90/MMP binding mechanism by mAb 4C5. This in turn prevented the metastatic deposit of tumour cells into the lung tissue. The conclusion was that 4C5 antibodies could have potential therapeutic use in cancer.
Tags: Collagen IV, Collagen IV antibody, HSP90, HSP90 antibody, Laminin 5, Laminin 5 antibody, MMP antibody, MMP13, MMP13 antibody, MMP2, MMP2 antibody, MMP3, MMP3 antibody, MMP7, MMP7 antibody, MMP9, MMP9 antibody
Posted in Angiogenesis, Antibodies, Antibody catalog, Antibody database, Antibody suppliers, Apoptosis, Cancer, Heat Shock Proteins, Tumor | No Comments »
Friday, February 10th, 2012
Mediating DNA damage is a crucial process, and one of the most important cellular guards against cancer. In response to DNA damage, sophisticated cellular machinery is recruited to repair the breaks, and if it fails, the cell is committed to death. Decades of research have elucidated the key players, and 53BP1 antibodies have revealed the protein to be central in the formation of DNA damage foci – regions flanking the chromatin of DSBs to which DNA repair factors are drafted.
In order to translocate to the nucleus, 53BP1 and other proteins must pass through nuclear pore complexes (NPCs), large channels that span the nuclear envelope. NPCs are made up of more than 30 types of nucleoporins, specialized proteins that facilitate the specific transport of proteins across the membrane. Recent evidence suggests that one nucleoporin in particular, NUP153, is essential for the localization of 53BP1 to the nucleus and the subsequent maintenance of genomic integrity. Using an siRNA screen, Moudry, et al. discovered the dependency of 53BP1 on NUP153, and began to characterize this unrecognized pathway. Their work establishes nuclear trafficking as a novel level of regulation involved in DNA damage repair network and cell fate decision making, creating potential for therapeutic targets. Additional work is needed to characterize the 53BP1/NUP153 pathway as well as those that involve other genome surveillance proteins such as FANCD2, RAD51, and BRCA1.
At Novus, we are proud to offer highly validated antibodies to all of these targets, and we have recently added new antibodies to NUP153 to our catalog. Please visit our website to learn more about a selection of DNA repair reagents.
Moudry P, et al. Nucleoporin NUP153 guards genome integrity by promoting nuclear import of 53BP1. Cell Death and Differentiation 2011; 1-10. [PMID: 22075984]
Tags: 53BP1, 53BP1 antibody, Apoptosis Research, BRCA1, BRCA1 antibody, Cancer Research, DNA Repair Research, FANCD2, FANCD2 antibody, Nuclear Pore Complex, Nucleoporin, NUP153, NUP153 antibody, Rad51, Rad51 antibody
Posted in Antibodies, Antibody catalog, Antibody database, Antibody suppliers, Apoptosis, Cancer, DNA Repair | No Comments »
Wednesday, February 8th, 2012
ATP-binding cassette superfamily F2 (ABCF2) is a member of the ATP-binding cassette (ABC) transporter superfamily, and more specifically, a member of the GCN20 subfamily. Most members of this family are membrane proteins that transport various substrates across the cell membrane [1, 2]. ABC genes have a pair of nucleotide binding folds (NBF) and trans-membrane (TM) domains; ABCF2 differs by having a pair of NBF’s but no TM domains. It is this distinction that leads most researchers to believe that ABCF2 does not have any membrane transport function, but instead may be involved in translational control, antibiotic resistance, and RNase L inhibition [1, 3].
Areas of study that utilize the ABCF2 protein include breast cancer, cervical cancer, clear cell ovarian adenocarcinoma, and endometrial cancer. Studies have found that ABCF2 may play a role in tumor suppression at metastatic sites, the endocrine pathway for breast cancer, and as a useful biomarker for cervical cancer [2, 3, 4]. Some breast cancers, being endocrine dependent cancers, utilize hormones for carcinogenesis. ABCF2 expression has been seen to increase in these types of breast cancer tissues. This suggests that ABCF2 may act as a surrogate marker for endocrine dependent proteins. There is also evidence that there is a relationship between ABCF2 expression and sensitivity to endocrine therapy [2].
The overexpression of ABCF2 was also found in conjunction with ectopic endometriosis [2]. However, ABCF2 expression is not related to prognosis or clinical factors such as age, stage, histologic type, histologic grade, and estrogen receptor status in endometrial cancer [3].
In cervical cancer, ABCF2 expression is found to be higher in stages III and IV. Currently, squamous cell antigen (SCC) is used as a marker for cervical cancer; however, there are conflicting reports on the accuracy of pretreatment SCC measurements as it pertains to prognostic significance [3]. In cervical non-squamous cell carcinoma, ABCF2 expression is prevalent. This ABCF2 expression correlated with overall survival in clinical trials. ABCF2 may therefore be a more useful biomarker for cervical non-squamous cell carcinoma [3].
- Dean, M., Rzhetsky, A., and Allikmets, R. 2001. The Human ATP-Binding Cassette [ABC] Transporter Superfamily. Genome Research. 11: 1156-1166.
- Hiroshi, T., Ito, Y.M., Ohashi, Y., Wong, K., Hashinguchi, Y., Welch, W., Berkowitz, R.S., Birrer, M.J., and Mok, S.C. 2005. Identification of overexpression and amplification of ABCF2 in clear cell ovarian adenocarcinomas by cDNA microarray analyses. Clin Cancer Res. 11: 6880.
- Nishimura, S., Tsuda, H., Miyagi, Y., Hirasawa, A., Suzuki, A., Kataoka, F., Nomura, H., Chiyoda, T., Banno, K., Fujii, T., Susumu, N., and Aoki, D. 2008. Can ABCF2 protein expression predict the prognosis of uterine cancer? British Journal of Cancer. 99: 1651-1655.
- Ogawa, Y., Tsuda, H., Hai, E., Tsuji, N., Yamahgata, S., Tokunaga, S., Nakazawa, K., Tamamori, Y., Ogawa, M., Shimizu, S., Inoue, T., and Nishiguchi, Y. 2006. Clinical role of ABCF2 expression in breast cancer. Anticancer Research. 26: 1809-1814.
Tags: ABCF2, ABCF2 Antibody, Breast Cancer, Cervical Cancer, Estrogen Receptor antibody, Membrane Transport, Ovarian Cancer, Translational Control
Posted in Antibodies, Antibody catalog, Antibody database, Antibody suppliers, Cancer, Tumor | No Comments »
Thursday, February 2nd, 2012
Bone and dentin are closely related tissues, formed when a type I collagen-rich extracellular matrix (ECM) is secreted from the osteoblasts or odontoblasts and subsequently mineralized. This process is tightly regulated by type I collagen plus a number of non-collagenous proteins, including members of the SIBLING (Small Integrin-Binding LIgand, N-linked Glycoprotein) family. Antibodies associated with this group include the Dentin Matrix Protein 1 (DMP1), Dentin Sialophosphoprotein (DSPP), Bone Sialoprotein (BSP) and Osteopontin (OPN).
The newest member of the family is Matrix Extracellular Phosphoglycoprotein (MEPE), of which presently little is known. However BSP, DSPP, DMP1 and OPN antibody studies suggest the proteins regulate crystal growth and mineralization of collagen fibers within the ECM during its conversion to bone or dentin.
Osteopontin antibody assays suggest little similarity between the amino acid sequence of OPN and those of its relatives. Nonetheless, the SIBLING proteins do share a number of common features, including an Arg-Gly-Asp (RGD) motif which binds to cell-surface integrins, allowing cell attachment and signalling. The RGD tri-peptide is always located on the last one or two exons (which are the largest) and all the SIBLING genes occupy a common chromosome location: 4q21-23. Finally, recent studies with SIBLING family antibodies have shown the proteins undergo a number of similar post-translational modifications, including phosphorylation, sulfuration, glycosylation, transglutaminase cross-linking and proteolytic processing.
Many of the mechanisms controlling bone and dentin synthesis remain elusive, but BSP and osteopontin antibody assays clearly show a link between SIBLING protein activity and PTMs, which must alter the structure and therefore function of the proteins in the same way histone modifications do.
Tags: Bone, BSP, BSP antibody, Dentin, Dentin antibody, DMP1, DMP1 antibody, DSPP, DSPP antibody, Histone, histone modification, MEPE, MEPE antibody, OPN, OPN antibody, osteopontin, osteopontin antibody, SIBLING protein family
Posted in Antibodies, Antibody catalog, Antibody database, Antibody suppliers, Bone Research | No Comments »
Wednesday, February 1st, 2012
Apoptosis is one of the best-characterized phenomena in cellular and molecular biology. Not only is it essential for successful development, but its deregulation also leads to a number of human diseases, most notably cancer. The cysteine aspartate protease (caspase) family of proteins has been studied extensively over the past several decades and found to play a pivotal role in the execution of apoptosis; caspase activation is regarded as commitment to programmed cell death. A variety of intrinsic and extrinsic stressors are capable of initiating mediated cell death, however, transduction commonly occurs via caspase activity. Initiator caspases (8, 9, 10 and 2) are activated first, generally by binding oligomeric adaptor proteins, and subsequently activate the effector caspases (3, 7 and 6) via proteolytic cleavage.
Recent research has revealed a novel role for caspases, notably caspase-8 and -3/7, in mediating neurotoxicity in response to inflammatory stimuli in microglia. Although microglia are the primary effectors of the immune response in the nervous system, numerous studies suggest that their aberrant activation contributes to neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s and multiple sclerosis. In their groundbreaking research, Burgillos, et al. show that exposure of microglia to pro-inflammatory cytokines leads to activation of caspase-3/7 and neurotoxicity associated with neurological disease. Surprisingly, they also demonstrated that inhibition of caspase-3/7 inhibited microglial activation, and that lipopolysaccharides failed to damage neighboring neurons when caspase-3/7 was abrogated chemically or with siRNA. Finally, they provide evidence that the IKK/NF-kB pathway—a canonical pro-inflammatory pathway– is also influenced by caspase-3/7 by their ability to trigger PKC-delta.
Neuronal inflammation is both a prominent cause and result of brain injury and the identification of caspase-3/7 and -8 in its etiology provides exciting new targets for potential therapies. Coupled with the advent of nano-carriers capable of traversing the blood brain barrier, caspase-3/7 could be promising substrates for novel anti-inflammatory drugs. Novus Biologicals provides several excellent antibodies to target caspase-3 and -7 (such as NB500-206 and NB500-210) that we hope will accelerate research in this field. We are committed to producing quality research materials, and look forward to learning how our caspase 3 and caspase 7 antibodies will serve the scientific community.
Burgillos MA, Deierborg T, Kavanagh E, et al. Caspase signaling controls microglia activation and neurotoxicity. Nature 2011; 472:319-324.
Tags: Casoase 7, Caspase, Caspase 10, Caspase 10 antibody, Caspase 2, Caspase 2 antibody, Caspase 3, caspase 3 antibody, Caspase 6, Caspase 6 antibody, Caspase 7 antibody, Caspase 8, Caspase 8 antibody, Caspase 9, Caspase 9 antibody, IKK, IKK antibody, Immune response, Inflammation, NFkB, NFkB antibody, PKC-delta, PKC-delta antibody
Posted in Alzheimer's, Antibodies, Antibody catalog, Antibody database, Antibody suppliers, Apoptosis, Cancer, Immunology, Inflammation, Neurodegeneration, Neuroscience, Parkinsons | No Comments »
