Antibody News

SREBP1 (sterol-regulatory-element-binding protein 2) is a basic-helix-loop-helix-leucine zipper (bHLH-ZIP) transcription factor. It regulates sterol and cholesterol homeostasis by controlling enzymes involved in cholesterol synthesis and uptake, e.g. HMG-CoA. The SREBP1 antibody was used in fundamental studies to dissect SREBP1 domains and downstream signaling (1). These studies identified domains for membrane attachment, DNA binding and transcriptional activation of effectors like the sterol regulatory element-1 (SRE-1) and Max, another bHLH-ZIP protein. SREBP1 modulates expression of the transmembrane protein ABCA1 (ATP-binding cassette transporter-A1) that is responsible for managing cellular cholesterol efflux.  ABCA1 mediates transport of lipids between the...

Telomerase reverse transcriptase (TERT) is a ribonucleoprotein enzyme essential for eukaryotic chromosomal termini replication. It is a useful marker as it is active only in progenitor and most cancer cells, but inactive or (active at very low activity) in normal somatic cells. TERT is the catalytic component of a much larger holoenzyme complex (consisting of TERT, DKC1, WDR79, NOP10, NHP2, NOLA1, TEP1, SMG6, POT1 and TERC) responsible for maintaining and elongating telomeres at chromosome ends. TERT behaves as a reverse transcriptase and adds simple repetitive sequences by copying a template sequence within the RNA component of the enzyme. Researchers at the Dana-Farber Cancer Institute...

The low density lipoprotein receptor coordinates the metabolism of cholesterol, an essential component of the mammalian cell plasma membranes. Study of this carefully balanced system has led to an enhanced understanding of cholesterol homeostasis at the cellular level. Receptor-mediated endocytosis (RME) is an important mechanism of metabolic regulation. Garbarino’s group used LDL receptor antibody and small hairpin RNA knockdown to show that knockdown of STARD4 in hepatocytes disrupts cholesterol trafficking between the plasma membrane, endoplasmic reticulum (ER), and endocytic recycling compartment (ERC...

Human IgG is a component of the immune system that protects the body from infection. It is the most abundantly found antibody isotype within the circulatory system of the human body. All antibody isotypes contain two heavy chains and two light chains that are arranged in a Y-shape. The IgG isotpye is found in blood, extracellular fluid, and colostrum among a wide variety of body fluids, and protects the fetus in utero because it is a small monomer capable of crossing the placenta.

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Prolyl-hydroxylase Domain Containing Protein 2 (PHD2) is one of four hydroxylase enzymes that function as oxygen sensors. They are responsible for the post-translational modification of hypoxia-inducible factor 1 alpha (HIF-1 alpha), a component of the transcriptional complex involved in oxygen homeostasis. PHDs catalyze the hydroxylation of prolyl residues on HIF-1 alpha and target it for proteasomal degradation via von Hippel-Lindau ubiquitination. The four isoforms appear to function in a non-redundant manner and appear to differ in their expression patterns and catalytic selectivity. PHD2 antibody provided new insights into the complex formation partners of the melanoma antigen-11 (MAGE-11) protein in a yeast two-hybrid...

Histones are highly conserved proteins that function in the organization of nuclear DNA to create chromatin in eukaryotic cells. Post-translational alterations of histones are critical to monitoring and regulating DNA structure, expression, and gene transcription. There are five histones: H1, H2A, H2B, H3, and H4. Histone H4 consists of 102 amino acid residues and frequently acts as a docking site for other histones. Histone H4’s N-terminal tail undergoes acetylation, methylation, and phosphorylation: all vital for regulation of gene transcription. The degree of modification is controlled by kinases and phosphates because the...

Adipose differentiation-related protein (ADFP; also known as ADRP or adipophilin), is a lipid droplet protein found in most cells and tissues. These lipids droplets may serve as local energy reserves or sources of lipid for membrane synthesis. Furthermore, they may protect cells from the harmful effects of excess lipid accumulation by sequestering toxic lipid species away from pathways leading to cell death (1). ADFP expression is strongly induced in cells with increased lipid load. ADFP was first isolated by differential hybridization screening of 1246 cells during their differentiation to adipocytes. Immunoblot of 1246 cell extracts with an antibody raised against the expressed ADRP showed that the 1246 cells contain a 50-kDa protein, the production of which increases as the cells differentiate (2). These observations suggest that adipocyte differentiation is accompanied by early expression of a mRNA...

ABCG1 (ATP-binding cassette sub-family G member 1) is a transporter protein that is primarily involved in macrophage lipid homeostasis. It is a member of the superfamily of ATP-binding cassette (ABC) transporters and localizes to intracellular compartments associated with endoplasmic reticulum and golgi membranes. Its expression is highest in macrophage-rich tissue such as spleen, lung, thymus, and brain. ABCG1 is expressed on the cell surface and in intracellular compartments of cholesterol-laden macrophages.

The extracellular matrix (ECM) is a well-structured composite of collagens, proteoglycans, glycoproteins, and growth factors proficient of generating variable measures of tissue tensile potency, from mucosal linings to bones. ECM predominantly comprises the cellular milieu outside the circulation and is established as having a major regulatory effect on cell activity.  There has been a considerable amount of attention towards the disparate conditions in which ECM unambiguously sends or alters signals to the surrounding cells. Interactions with ECM influence virtually all features of necessary cellular functions which include proliferation, migration, along with that of protein and gene expression and cell delineation. Specific cell-matrix interactions are critical for the endurance of many cell types, and loss of this adhesion dependence is a classic hallmark of neoplastic change. ECM remodeling promotes tumor...

The Lin28-Let-7 stem cell differentiation regulatory pathway is responsible for maintaining stem cell pluripotency. Specifically, Lin28 causes uridiylation of the let-7 miRNA precursor, which prevents differentiation processing by Dicer. Instead, the Uridylated let-7 is degraded by a previously unidentified exonuclease protein. In the article “A role for the Perlman syndrome exonuclease Dis3l2 in the Lin28-let-7 pathway” HM Chang, et al. used Novus’ Dis3l2 Antibody (NBP1-84740) to identify Dis3l2 as the exonuclease responsible for uridylated let-7 degradation.  Interestingly, Dis3l2 binds several proteins previously implicated in Perlman Sydrome.

The implications of this finding are two-fold: (1) The data suggests that Dis3l2 helps maintain pluripoentcy in stem cells, and (2) although speculative, the Lin28-let-7 pathway may be relevant to Perlman Sydrome and cancer.  Additional research is...

Synaptonemal Complex Protein 1 (SCP1) is a novel tumor antigen that belongs to the growing family of cancer/testis antigens (CTAs). CTAs are theoretically ideal targets for tumor immunotherapy. Unlike most auto-antigens, CTAs are highly immunogenic, even in the autologous cancer-bearing patients. Furthermore, because of their very restricted normal tissue expression, immunotherapy targeting CTAs is expected to be more specific and less toxic. These two theoretical properties of CTAs have arisen from the belief that, because they are testicular-specific, they are normally only expressed in the immune privileged testicles where there is an apparent lack of human leukocyte antigen (HLA) class I molecules on the surface of germ cells (1).

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E-cadherin (also known as Arc-1, uvomorulin, and cell-CAM 120/80) is a calcium-regulated adhesion molecule expressed in most normal epithelial tissues and the loss of E-cadherin can cause dedifferentiation and invasiveness in several cancers (1). Loss of E-Cadherin expression correlated with the invasiveness of carcinoma (2). Carcinoma cell lines with an epithelioid phenotype were noninvasive and expressed E-cadherin suggesting a reciprocal relationship between levels of E-Cadherin expression and their invasiveness as detected by E-Cadherin antibodies (3).

Reduced expression of E-cadherin by IHC has been...