Search results

Excess adiposity is the most important risk in the development of insulin resistance and type 2 diabetes mellitus (T2DM). Adipose tissue produces several proteins (adipocytokines) such as leptin, adiponectin, resistin, tumor necrosis factor-?, and IL-6, that modulate insulin sensitivity and appear to play an important role in the pathogenesis of insulin resistance, diabetes, dyslipidemia, inflammation, and atherosclerosis. However, the mechanisms by which fat tissue induces insulin resistance and the role of adipocytokines in the pathogenesis of T2DM have not been well established. Visfatin, also known as pre-B cell colony-enhancing factor (PBEF), is a cytokine that is highly expressed in visceral fat and was originally isolated as a secreted factor that synergizes with IL-7 and stem cell factors to promote the growth of B cell precursors. Visfatin homologs have been identified in carp, invertebrate mollusks, and bacteria, as well as in vertebrates, including humans and the mouse. It has been postulated to play a role in innate immunity.
Visfatin exerts insulin-mimetic effects that are dose-dependent and quantitatively similar to those of insulin in stimulating muscle and adipocyte glucose transport, and in inhibiting hepatocyte glucose production. Intravenous injection of recombinant visfatin in mice decreased plasma glucose in a dose-dependent fashion. In keeping with its insulin-mimetic effects, visfatin was as effective as insulin in reducing hyperglycemia in insulin-deficient diabetic mice. Visfatin was also found to be bound to and activate insulin receptor, causing receptor phosphorylation and the activation of downstream signaling molecules. However, visfatin and insulin did not compete for binding to the insulin receptor, indicating that the two proteins were recognized by different regions of the receptor. Thus, visfatin might play a role in glucose homeostasis and dysregulation in biosynthesis or signal transduction, and might contribute to the pathogenesis of diabetes.

Tumor necrosis factor is a cytokine involved in systemic inflammation and is a member of a group of cytokines that all stimulate the acute phase reaction. TNF is mainly secreted by macrophages.
TNF causes apoptotic cell death, cellular proliferation, differentiation, inflammation, tumorigenesisand viral replication, TNF is also involved in lipid metabolism, and coagulation. TNF's primary role is in the regulation of immune cells.
Dysregulation and, in particular, overproduction of TNF have been implicated in a variety of human diseases- autoimmune diseases, insulin resistance, and cancer.

DNA Cytosine-5--Methyltransferase 3-Like (DNMT3L) is a nuclear protein with similarity to DNA methyltransferases, but is not believed to act as a DNA methyltransferase since it doesn’t contain the amino acid residues needed for methyltransferase activity. Nevertheless, DNMT3L stimulates de novo methylation by DNA cytosine methyltransferase 3 alpha and is assumed to be required for the formation of maternal genomic imprints. DNMT3L also mediates transcriptional repression as a result of interaction with histone deacetylase 1. DNMT3L is a catalytically inactive regulatory factor of DNA methyltransferases, which is vital for the function of DNMT3A and DNMT3B. DNMT3L activates DNMT3A and DNMT3B by binding to their catalytic domain. Furthermore, DNMT3L accelerates the binding of DNA and AdoMet to the methyltransferases and dissociates from the complex after DNA binding to the methyltransferases.

The AsnRS enzyme is a member of the ligases family, specifically those forming carbon-oxygen bonds in aminoacyl-tRNA and related compounds. An asparagine-tRNA ligase is an enzyme which catalyzes the chemical reaction: ATP + L-asparagine + tRNAAsn AMP + diphosphate + L-asparaginyl-tRNAAsn. The three substrates of the AsnRS enzyme are ATP, L-asparagine, and tRNA(Asn), whereas its three products are AMP, diphosphate, and L-asparaginyl-tRNA(Asn).

Tumor necrosis factor receptor superfamily member 8 (TNFRSF8) is a receptor for TNFSF8/CD30L. TNFRSF8 has a role in the regulation of cellular growth and transformation of activated lymphoblasts. In addition, the TNFRSF8 protein regulates gene expression via activation of NF-kappa-B. TNFRSF8 being a regulator of apoptosis, induces cell death or proliferation, depending on the cell type.

TAFA-2 is a 11 kDa secreted protein that belongs to the FAM19/TAFA family of chemokine-like proteins. Similar to other FAM19/TAFA family members, mature TAFA-1 contains 10 regularly spaced cysteine residues with the same pattern: CX7CCX13CXCX14CX11CX4CX5CX10C (C symbolizes a conserved cysteine residue and X symbolizes any noncysteine amino acid). Human TAFA-2 is 97% aa identical to mouse TAFA-2 and is expressed in the central nervous system (CNS), colon, heart, lung, spleen, kidney, and thymus, however its expression in the CNS is 50 to 1000 fold higher than in other tissues. The biological roles of TAFA family members have not yet been determined.

IFN-gamma produced by lymphocytes activated by specific antigens or mitogens.
IFN-gamma, in addition to having antiviral activity, has important immunoregulatory functions, it is a potent activator of macrophages, and has antiproliferative effects on transformed cells and it can potentiate the antiviral and antitumor effects of the type I IFNs.

Tumor necrosis factor receptor superfamily member 21 or TNFRSF21, is a protein that located in the cell membrane from the TNF receptor superfamily. By activating the NF-kappaB pathway, TNFRSF21 promotes cell apoptosis. The degeneration of cells caused by activating caspase 3 and caspase 6, the TNFRSF21 binds to the N-terminal APP in neuronal cell bodies and axons which leads to apoptosis. TNFRSF21 takes part in signaling cascades activated by stimulation of T-cell receptor.

CTF2P, aka Neuropoietinis a part of the IL-6 family of cytokines. CTF2P is the outcome of a gene duplication event involving cardiotrophin-1 (CT-1) and it helps to define a subfamily within the IL-6 family that includes CT-1, CLC and CTNF. CTF2P Increases the platelet count associated with splenomegaly and takes part in neuronal precursor development and maturation.

Coagulation factor VIII participates in the intrinsic pathway of blood coagulation; factor VIII is a cofactor for factor IXa which, in the presence of Ca+2 and phospholipids, converts factor X to the activated form Xa. This gene produces two alternatively spliced transcripts. Transcript variant 1 encodes a large glycoprotein, isoform a, which circulates in plasma and associates with von Willebrand factor in a noncovalent complex. This protein undergoes multiple cleavage events. Transcript variant 2 encodes a putative small protein, isoform b, which consists primarily of the phospholipid binding domain of factor VIIIc. This binding domain is essential for coagulant activity. Defects in this gene results in hemophilia A, a common recessive X-linked coagulation disorder.

Cardiotrophin 1 (CT-1) is a 201 amino acid member of the interleukin-6 superfamily. It was identified by its ability to induce hypertrophic response in cardiac myocytes. CT-1 mRNA levels were found both in cardiac myocytes and in cardiac nonmyocytes. CT 1 was also detected in abundance in normal adult human lung and was expressed in both fetal and adult airway smooth muscle cells. CT 1 activates gp130 dependent signaling and stimulates the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway to transduce hypertrophic and cytoprotective signals in cardiac myocytes.
CT 1 has also a neurotrophic function. CTF1 deficiency causes increased motoneuron cell death in spinal cord and brainstem nuclei of mice during a period between embryonic day 14 and the first postnatal week. Moreover, CT-1 is a hepatocyte survival factor that efficiently reduces hepatocellular damage in animal models of acute liver injury. Cardiotrophin 1 expression is augmented after hypoxic stimulation and it can protect cardiac cells when added either prior to simulated ischaemia or at the time of reoxygenation following simulated ischaemia. Cardiotrophin 1 can induce expression of the protective heat shock proteins (hsps) in cardiac cells.
Cardiotrophin-1 increased ventricular expression of ANP, brain natriuretic peptide (BNP) and angiotensinogen mRNA.
Cardiophin 1 levels were significantly elevated in patients with heart failure, patients with dilatative cardiomyopathy, moderate/severe mitral regurgitation, stable and unstable angina and after acute myocardial infarction.

Thymalfasin is a synthetic analogue of thymosin-alpha-1, a 28-amino acid protein derived from the precursor protein prothymosin-alpha. Exhibiting a variety of immunoregulating properties, thymosin-alpha-1 induces differentiation of murine T-cell precursors and human thymocytes and the terminal differentiation of functionally immature cord blood lymphocytes and induces production of IL-2, high affinity IL-2 receptors, and B-cell growth factors by peripheral blood mononuclear cells. T-helper and cytotoxic/suppressor T-cell populations are targets of thymosin activity. Thymosin-alpha-1 has been shown to increase the efficiency of antigen presentation by macrophages and to be an endogenous modulator of alpha-thrombin activity.

Thrombin enzyme (Activated Factor IIa) is an important clotting promoter that controls the transformation of soluble fibrinogen to insoluble active fibrin strands. Thrombin is a coagulation protein and a serine protease (EC 3.4.21.5) that catalyzes many coagulation-related reactions. Thrombin triggers factor-XI, factor-V, Factor-XIII and factor-VIII. Thrombin endorses platelet activation, using activation of protease-activated receptors on the platelet. As a result of its high proteolytic specificity, thrombin has become an important biochemical protein. The thrombin cleavage site (Leu-Val-Pro-Arg-Gly-Ser) is widely used in linker regions of recombinant fusion protein constructs. After the purification of the fusion protein, thrombin is used to cleave between the Arginine and Glycine residues of the cleavage site, efficiently removing the purification tag from the protein of interest with a high degree of specificity.

Hepatitis B is one of a few known non-retroviralviruses which employ reverse transcriptionas a part of its replication process. (HIV, a completely unrelated virus, also uses reverse transcription, but it is a retrovirus.) HBV invades the cell by binding to surface receptor and become internalized. The viral core particles then migrate to the hepatocyte nucleus and the partially double-stranded, relaxed circular genomes (RC-DNA) are repaired to form a covalently closed circular DNA (cccDNA), which is the template for viral genomic and sub-genomic RNAs by cellular RNA polymerase II. Of these, the pregenomic RNA(pgRNA is selectively packaged into progeny capsids and is then reverse-transcribed into new RC-DNA. The core can either bud into the endoplasmic reticulum to be enveloped or exported from the cell or recycled back into the genome for conversion to cccDNA.

Parathyroid hormone (PTH), or parathormone, is secreted by the parathyroid glands as a polypeptide containing 84 amino acids. It acts to increase the concentration of calcium in the blood, whereas calcitonin (a hormone produced by the parafollicular cells of the thyroid gland) acts to decrease calcium concentration. PTH acts to increase the concentration of calcium in the blood by acting upon parathyroid hormone receptor in three parts of the body: In the bones- It enhances the release of calcium from the large reservoir contained in the bones. Bone resorption is the normal destruction of bone by osteoclasts, which are indirectly stimulated by PTH. Stimulation is indirect since osteoclasts do not have a receptor for PTH; rather, PTH binds to osteoblasts, the cells responsible for creating bone. Binding stimulates osteoblasts to increase their expression of RANKL, which can bind to osteoclast precursors containing RANK, a receptor for RANKL. The binding of RANKL to RANK stimulates these precursors to fuse, forming new osteoclasts which ultimately enhances the resorption of bone. In the kidney- It enhances active reabsorption of calcium from distal tubules and the thick ascending limb. In the intestine- It enhances the absorption of calcium in the intestine by increasing the production of vitamin D and upregulating the enzyme responsible for 1-alpha hydroxylation of 25-hydroxy vitamin D, converting vitamin D to its active form (1,25-dihydroxy vitamin D) which effects the actual absorption of calcium (as Ca2+ ions) by the intestine via calbindin.

IFN-alpha is produced by macrophages and has antiviral activities. Interferon stimulates the production of two enzymes: protein kinase and an oligoadenylate synthetase.

FHIT is a member of the histidine triad gene family. FHIT gene encodes a diadenosine 5',5'''-P1,P3-triphosphate hydrolase involved in purine metabolism. FHIT gene includes the common fragile site FRA3B on chromosome 3, where carcinogen-induced damage can lead to translocations and abnormal transcripts of this gene. The FHIT protein is a tumor suppressor with reduced or no expression in numerous types of cancer. FHIT may also act as a tumor suppressor in normal cells. Alterations and deletions of the FHIT (Fragile Histidine Triad) gene are strongly linked to the genesis and establishment of human tumors of the lung, cervix, breast, colon, stomach, and pancreas. The expression of FHIT is more often lost in cancers of individuals with familial mutations causing deficiency in DNA repair genes such as BRCA1, BRCA2 and MSH2. In vitro FHIT functions as a hydrolase that cleaves diadenosine triphosphate (Ap3A) to ADP and AMP. The FHIT -Ap3A enzyme-substrate complex seems to be the tumor suppressor signal. The restoration of FHIT expression in FHIT -deficient cancer cells leads to apoptosis, involving the intrinsic caspase pathway, in cancer-derived cells and in tumor xenografts.

Trafficking protein particle complex 4 (TRAPPC4) is part of the multisubunit TRAPP (transport protein particle) complex and interacts with SDC2. TRAPPC4 has a role in vesicular transport from endoplasmic reticulum to Golgi.

METTL1 is recognized as tRNA (guanine-N(7)-)-methyltransferase that is a part of the methyltransferase superfamily. METTL1 displays high sequence similarity to yeast ORF YDL201w and can be inactivated by phosphorylation. METTL1 protein has a conserved S-adenosylmethionine-binding motif and ccatalyzes the formation of N(7)-methylguanine at position 46 (m7G46) in tRNA.

ST6GAL1 also known as ST6 Beta-Galactosamide Alpha-2,6-Sialyltranferase 1, is part of the glycosyltransferase family 29. ST6GAL1 is a type II membrane protein which catalyzes the transfer of sialic acid from CMP-sialic acid to galactose-containing substrates. Furthermore, ST6GAL1 is normally found in the Golgi however it can be proteolytically processed to a soluble form, ST6GAL1 is also involved in the generation of the cell-surface carbohydrate determinants as well differentiation antigens HB-6, CD75, and CD76.

ETF is a heterodimer composed of alpha and beta subunit. ETFB protein is electron-transfer-flavoprotein, beta polypeptide that transports electrons between primary flavoprotein dehydrogenases involved in mitochondrial fatty acid and amino acid catabolism and the membrane-bound electron transfer flavoprotein ubiquinone oxidoreductase.

TAF10 is a small subunit of TFIID which is related to a subdivision of TFIID complexes. Studies with human and mammalian cells verified that this subunit is mandatory for transcriptional activation by the estrogen receptor, for progression through the cell cycle, and is essential for several cellular differentiation programs.

PFN2 is a ubiquitous actin monomer-binding protein which is part of the profilin family. PFN2 regulates actin polymerization in response to extra cellular signals. PFN2 binds to actin and affects the structure of the cytoskeleton. At high concentrations, profilin prevents the polymerization of actin, while it increases it at low concentrations. PFN2 binds to PIP2, it inhibits the formation of IP3 and DG.