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A 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.

NANOG is a multidomain homeobox transcription factor which functions to maintain the undifferentiated state of pluripotent stem cells. NANOG expression counteracts the differentiation-promoting signals induced by the extrinsic factors LIF, Stat3 and BMP. Once NANOG expression is downregulated, cell differentiation can proceed. Proteins which regulate NANOG expression include transcription factors Oct4, SOX2, FoxD3, and Tcf3 and tumor suppressor p53.

CD320 is a part of the low-density lipoprotein receptor family, having 2 low-density lipoprotein receptor type A domains divided by a complement-like cysteine-rich region. CD320 participates in cobalamin uptake and internalizes the complex by endocytosis. CD320 is also plays a role as costimulator to promote B cell and follicular dendritic cells responses. CD320 is also known to augment the proliferation of PC precursors generated by IL-10.

Salmonella Typhi is a pathogen causing typhoid fever, affecting over 17 million people with approximately 600,000 deaths annually worldwide. If untreated, typhoid fever cases result in mortality rates ranging from 12-30%.

FLT3 ligand is a receptor for the fl cytokine has a tyrosine-protein kinase activity & a growth factor that regulates proliferation of early hematopoietic cells. Flt3-Ligand synergizes with other CSFs and interleukins to induce growth and differentiation.

Myristate, a rare 14-carbon saturated fatty acid, is co-translationally attached by an amide linkage to the N-terminal glycine residue of cellular & viral proteins with various functions. N-Myristoyltransferase 1, also known as NMT1 catalyzes the transfer of myristate from CoA to proteins. NMT1 seems to be irreversible and is essential for full expression of the biologic activities of several N-myristoylated proteins, as well as the alpha subunit of the signal-transducing guanine nucleotide-binding protein, G protein.

Calnexin (CANX) belongs to the calnexin family of molecular chaperones. Calnexin is a calcium-binding, ER-associated protein that interacts briefly with newly synthesized N-linked glycoproteins, facilitating protein folding and assembly. Calnexin may also have a key role in the quality control of protein folding by retaining incorrectly folded protein subunits within the ER for degradation. Calnexin grants long-term protection of wild-type Shaker protein from ER-associated degradation. Polypeptide substrate recognition by Calnexin requires specific conformations of the Calnexin protein. Calnexin dwindles with aging and might contribute to a cytoprotection in an array of human age-related diseases.

Lymphotoxin Beta Receptor, also known as LTBR takes part in signaling during the development of lymphoid and other organs, lipid metabolism, immune response, and programmed cell death. In addition, the activity of this receptor has been associated to carcinogenesis. Alternatively spliced transcript variants encoding multiple isoforms have been observed for LTBR.

MHC Class I is a membrane spanning molecule consisting of 2 proteins. MHC Class I is just about 350 amino acids in length, with roughly 75 amino acids at the carboxylic end comprising the transmembrane and cytoplasmic portions. The remaining 270 amino acids, are divided into three globular domains labeled Alpha-1, Alpha-2 and Alpha-3 prime, with Alpha-1 being closest to the amino terminus and Alpha-3 closest to the membrane. The second portion of the molecule is a small globular protein called Beta-2 Microglobulin. It links primarily with the Alpha-3 prime domain and is essential for MHC stability.
The MHC ability to show a vast range of antigenic peptides for T cell recognition needs a compromise between broad specificity and high affinity. Both MHC class I and MHC class II show an exceptional structure while the peptide main chain is tightly bound and peptide side chains show less restrictive interactions. It is primarily the peptide side-chain contacts and conformational variability that ensures that the peptide-MHC complex presents an antigenically unique surface to T cell receptors.

CD79B is a 36 kDa trans membrane glycoprotein belonging to the immunoglobulin superfamily. Heterodimers of CD79A and CD79B connect with a membrane attached immunoglobulin on the B cell surface to create the B cell antigen receptor complex (BCR). CD79A and CD79B are essential for BCR-mediated signaling and subsequently for the development and activation of B lineage cells.

CD200 is a type-1 membrane glycoprotein which is a part of the immunoglobulin superfamily due to its 2 immunoglobulin domains. CD200 regulates myeloid cell activity and delivers an inhibitory signal for the macrophage lineage in various tissues. CD200 is also Costimulates T-cell proliferation.

Killer-cell immunoglobulin-like receptors (KIRs), are a family of cell surface glycoproteins found on Natural Killer (NK) Cells, which are important cells of the immune system. They control the killing function of these cells by interacting with MHC class I molecules, which are expressed on all cell types. This interaction allows them to identify virally infected cells or tumor cells that have a distinctive low level of Class I MHC on their surface. The majority of KIRs are inhibitory, which means that their recognition of MHC suppresses the cytotoxic activity of their NK cell. Only a limited number of KIRs have the capacity to activate cells.
The KIR genes are found in a cluster on chromosome 19q13.4 within the 1 Mb leukocyte receptor complex (LRC). KIR molecules are extremely polymorphic, meaning their gene sequences differ significantly between individuals, so that different individuals have different arrays/repertoires of KIR genes.
The KIR proteins are categorized by the number of extracellular immunoglobulin domains (2D or 3D) and by whether they have a long (L) or short (S) cytoplasmic domain. KIR proteins with the long cytoplasmic domain transduce inhibitory signals upon ligand binding via an immune tyrosine-based inhibitory motif (ITIM). Whereas KIR proteins with the short cytoplasmic domain lack the ITIM motif and instead associate with the TYRO protein tyrosine kinase binding protein to transduce activating signals.
KIR2DL3 is an inhibitory Killer Cell Ig-like Receptor (KIR, previously called p58 KIR, cl-6, NKAT2 or KIR-K7), which recognizes class I MHC molecules (HLA-Cw1, -Cw3, -Cw7, and Cw8). KIR2DL3 inhibits the activity of NK cells thus preventing cell lysis.

CD74 (HLA class II histocompatibility antigen gamma chain isoform b), is a transmembrane protein (on antigen presenting cells) which is the invariant chain that chaperones MHC class IIdimers from the endoplasmic reticulum to the cell surface. CD74 is expressed by cells of both T lymphocyte and Blymphocyte lineages. CD74 upregulated in several cancers and is also expressed by non immune cells during inflammation. Diseases related with CD74 include thymic epithelial neoplasm and gastroduodenitis. Among its related super-pathways are Immune System and Immune response Antigen presentation by MHC class II. In addition CD74 functions as cell surface receptor for the cytokine MIF.

Low affinity immunoglobulin gamma Fc region receptor III-A (FCGR3A) is a receptor for the Fc portion of immunoglobulin G, and is involved in the elimination of antigen-antibody complexes from the circulation, as well as other antibody-dependent responses. FCGR3A needs to associate with the gamma subunit of Fc epsilon. The FCGR3A receptor is expressed on natural killer (NK) cells as an integral membrane glycoprotein anchored through a transmembrane peptide, while FCGR3B is expressed on polymorphonuclear neutrophils (PMN) where the receptor is anchored through a phosphatidylinositol (PI) linkage. In addition, FCGR3A is expressed on macrophages, subpopulation of T-cells, immature thymocytes and placental trophoblasts. FCGR3A mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis. FCGR3A gene mutations are linked with susceptibility to recurrent viral infections, susceptibility to systemic lupus erythematosus, and alloimmune neonatal neutropenia.

B-cell CLL/lymphoma 7A (BCL7A) is a member of the BCL7 family. BCL7A is directly involved, with Myc and IgH, in a three-way gene translocation in a Burkitt lymphoma cell line. Thru gene translocation, the N-terminal region of the BCL7A gene is disrupted, which is assumed to be connected to the pathogenesis of a subset of high-grade B cell non-Hodgkin lymphoma. The N-terminal portion involved in the translocation includes the region which shares a compelling sequence similarity with those of BCL7B and BCL7C. Chromosomal anomalies involving BCL7A may be a cause of B-cell non-Hodgkin lymphoma.

PDZK1 is a PDZ domain-containing scaffolding protein which facilitates localization of cell surface proteins and has a key part in cholesterol metabolism by regulating the HDL receptor, scavenger receptor class B type 1. Single nucleotide polymorphism in this gene is linked to metabolic syndrome, and overexpression results in drug resistance of multiple myeloma.

Chemokine (C-C motif) ligand 7 (CCL7) is a small cytokine known as a chemokine that was previously called monocyte-specific chemokine 3 (MCP3). Due to CCL7 possessing two adjacent N-terminal cysteine residues in its mature protein, it is classified among the subfamily of chemokines known as CC chemokines. CCL7 specifically attracts monocytes, and regulates macrophage function. It is produced by certain tumor cell lines and by macrophages. This chemokine is located on chromosome 17 in humans, in a large cluster containing many other CC chemokines and is most closely related to CCL2(previously called MCP1).

IL3 is a potent growth promoting cytokine. This cytokine is capable of supporting the proliferation of a broad range of hematopoietic cell types. It is involved in a variety of cell activities such as cell growth, differentiation and apoptosis. This cytokine has been shown to also possess neurotrophic activity, and it may be associated with neurologic disorders.

Low affinity immunoglobulin gamma Fc region receptor III-A (FCGR3A) is a receptor for the Fc portion of immunoglobulin G, and is involved in the elimination of antigen-antibody complexes from the circulation, as well as other antibody-dependent responses. FCGR3A needs to associate with the gamma subunit of Fc epsilon. The FCGR3A receptor is expressed on natural killer (NK) cells as an integral membrane glycoprotein anchored through a transmembrane peptide, while FCGR3B is expressed on polymorphonuclear neutrophils (PMN) where the receptor is anchored through a phosphatidylinositol (PI) linkage. In addition, FCGR3A is expressed on macrophages, subpopulation of T-cells, immature thymocytes and placental trophoblasts. FCGR3A mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis. FCGR3A gene mutations are linked with susceptibility to recurrent viral infections, susceptibility to systemic lupus erythematosus, and alloimmune neonatal neutropenia.

Small Ubiquitin-like Modifiers (SUMOs) are a family of small, related proteins that can be enzymatically attached to a target protein by a post-translational modification process termed sumoylation. Unlike ubiquitination, which targets proteins for degradation, sumoylation participates in a number of cellular processes, such as nuclear transport, transcriptional regulation, apoptosis, and protein stability. All SUMO proteins share the conserved ubiquitin domain and the C-terminal diglycine cleavage/attachment site. Human SUMO2, also known as Sentrin2 and SMT3B is synthesized as a 95 amino acid (aa), 11 kDa propeptide that contains a two aa C-terminal prosegment, and an 18 aa N-terminal protein interacting region (aa 33 -50). Following prosegment cleavage, the C-terminal glycine is enzymatically attached to a lysine on a target protein. Human SUMO2 shares 100% sequence identity to SUMO-2 from mouse. SUMO2 also has very high sequence homology to SUMO3 and SUMO4, 86 % and 85%, respectivel

Inhibitor of Growth Family, Member 2 (ING2) belongs to the inhibitor of growth (ING) family. ING family members associate with and modulate the activity of histone acetyltransferase (HAT) and histone deacetylase (HDAC) complexes and serve in DNA repair and apoptosis. ING2 appears to be involved in p53/TP53 activation and p53/TP53-dependent apoptotic pathways, most likely by enhancing acetylation of p53/TP53. ING2 is a component of an mSin3A-like corepressor complex, which is probably involved in deacetylation of nucleosomal histones. ING2 activity is modulated by binding to phosphoinositides (PtdInsPs).

HCV is a small 50nm, enveloped, single-stranded, positive sense RNAvirus in the family Flaviviridae. HCV has a high rate of replication with approximately one trillion particles produced each day in an infected individual. Due to lack of proofreading by the HCV RNA polymerase, the HCV has an exceptionally high mutation rate, a factor that may help it elude the host's immune response. Hepatitis C virus is classified into six genotypes(1-6) with several subtypes within each genotype. The preponderance and distribution of HCV genotypes varies globally. Genotype is clinically important in determining potential response to interferon-based therapy and the required duration of such therapy. Genotypes 1 and 4 are less responsive to interferon-based treatment than are the other genotypes (2, 3, 5 and 6).