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Complement C4c is a degradation product of C4b which is cleaved by C4b/C3b inactivator to yield C4d and C4c.
Complement C4c interacts with C1 and C2 to form C3 convertase of the classic activation pathway. Systemic lupus erythematosus (SLE) is often associated with congenital C4 deficiency. Reduced levels of components of the classic pathway (C1, C2, C4, C3) are common after such activation, e.g. in SLE, acute serum sickness and conditions associated with circulating immune complexes.

Lipopolysaccharides (LPS) are a type of glycolipids on the outer cell wall of Gram-negative bacteria. Lipopolysaccharide binding protein (aka LBP) is a plasma protein which facilitates the diffusion of bacterial LPS (endotoxin). LBP is involved in the acute-phase immunologic response to gram-negative bacterial infections. In cooperation with bactericidal permeability-increasing protein (BPI), LBP binds LPS and interacts with the CD14 receptor, most likely playing a role in regulating LPS-dependent monocyte responses. LBP belongs to a family of structurally and functionally related proteins, including BPI, plasma cholesteryl ester transfer protein (CETP), and phospholipid transfer protein (PLTP). The LBP gene is found on chromosome 20, directly downstream of the BPI gene. LBP catalyzes the transfer of LPS monomers from LPS aggregates to HDL particles, to phospholipid bilayers, and to a binding site on soluble CD14 (sCD14). sCD14 is capable of speeding up the transfer by receiving an LPS monomer from an LPS aggregate, and then yielding it to an HDL particle, therefore acting as a soluble "shuttle" for an insoluble lipid.

Beta Defensin 116, also known as DEFB116 is a member of the beta-defensin family.DEFB116 has antibacterial activity. The innate immune system includes antimicrobial peptides that protect multicellular organisms from a diverse spectrum of microorganisms. In addition, Beta-Defensins contain one important family of mammalian antimicrobial peptides.

SERF2 (small EDRK-rich factor 2) is a member of the SERF family. SERF2 is a protein-coding gene. Among the diseases associated with SERF2 are spinal muscular atrophy, and muscular atrophy.

Chemokine (C-X-C motif) ligand 1 (CXCL1) is a small cytokine belonging to the CXC chemokine family that was previously called GRO1 oncogene, Neutrophil-activating protein 3 (NAP-3) and melanoma growth stimulating activity, alpha (MSGA-a). It is secreted by human melanoma cells, has mitogenic properties and is implicated in melanoma pathogenesis. CXCL1 is expressed by macrophages, neutrophils and epithelial cells, and has neutrophil chemoattractant activity. CXCL1 plays a role in spinal cord development by inhibiting the migration of oligodendrocyte precursors and is involved in the processes of angiogenesis, inflammation, wound healing, and tumorigenesis. This chemokine elicits its effects by signaling through the chemokine receptor CXCR2. The gene for CXCL1 is located on human chromosome 4 amongst genes for other CXC chemokines.

CB1 cannabinoid receptor-interacting protein 1 (CNRIP1) is a 164 amino acid protein and G-protein coupled receptor which is a member of the CNRIP family. The CNRIP1 interacts with the C-terminal tail of cannabinoid receptor 1. CNRIP1 is expressed in the brain tissue and, at low levels, in the testis. CNRIP1 is involved in appetite, synaptic plasticity, neuroprotection and analgesia.

Kallikreins are a subgroup of serine proteases having various physiological functions. Many kallikreins are implicated in carcinogenesis and some have potential of becoming novel cancer and other disease biomarkers. Kallikrein-13 (KLK13) is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. KLK13 gene expression is regulated by steroid hormones and may be useful as a marker for breast cancer.

The HIV1 p24 His Tag protein performs complex orchestrated tasks during the assembly, budding maturation and infection stages of the viral replication cycle. Throughout viral assembly, the proteins form membrane associations and self-associations that ultimately result in budding of an immature virion from the infected cell. HIV-1 P24 gag, the key capsid protein of the HIV-1 virion, is used in clinical trials as one of the components of the HIV-1 vaccine because of the great extent of sequence homology between different isolates.

SEPT2 is a GTPase which is mandatory for cytokinesis and related to exocytosis. Septin-2 protein is able to hetero-oligomerize with Septin6, 7 and in addition takes part in the organization of new growth in organisms. SEPT2 is associated with a Tau-based paired helical filament core and contributes to the creation of neurofibrillary tangle as integral constituents of paired helical filaments.

p38a/SAPK2 is a member of the MAP kinase family. MAP kinases act as an integration point for multiple biochemical signals, and are involved in a wide variety of cellular processes such as proliferation, differentiation, transcription regulation and development. This kinase is activated by various environmental stresses and proinflammatory cytokines. The activation requires its phosphorylation by MAP kinase kinases (MKKs), or its autophosphorylation triggered by the interaction of MAP3K7IP1/TAB1 protein with this kinase. The substrates of this kinase include transcription regulator ATF2, MEF2C, and MAX, cell cycle regulator CDC25B, and tumor suppressor p53, which suggest the roles of this kinase in stress related transcription and cell cycle regulation, as well as in genotoxic stress response. Four alternatively spliced transcript variants of this gene encoding distinct isoforms have been reported.

Beta-crystallin A4 (CRYBA4) is a member of the beta/gamma-crystallin family which are the dominant structural components of the vertebrate eye lens. Beta-crystallins construct aggregates of various sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. The CRYBA4 gene being a beta acidic group member is part of a gene cluster with beta-B1, beta-B2, and beta-B3.

Macrophage Inflammatory Proteins belong to the family of chemotactic cytokines known as chemokines. In humans, there are two major forms, MIP-1a and MIP-1b that are now also named CCL3 and CCL4. Both factors are produced by macrophages after they are stimulated with bacterial endotoxins. MIP-1a and MIP-1b activate human granulocytes (neutrophils, eosinophils and basophils) which can lead to acute neutrophilic inflammation. MIP-1a and MIP-1b induce synthesis and release of other pro-inflammatory cytokines such as interleukin-1 (IL-1), IL-6 and TNF-alpha from fibroblasts and macrophages. CCL3 and CCL4 genes are both located on human chromosome 17.

Neuregulin/Heregulin is a family of structurally related polypeptide growth factors which are stemmed from alternatively spliced genes (NRG1, NRG2, NRG3 and NRG4). Thus far, there are more than 14 soluble and transmembrane proteins derived from the NRG1 gene. Proteolytic processing of the extracellular domain of the transmembrane NRG1 isoforms release soluble growth factors. These isoforms contain the heregulins (HRGs), glial growth factors (GGFs) and sensory and motor neuron-derived factor (SMDF). All these factors have the Ig and EGF-like domain, and are able to bind to ErbB3 and ErbB4 receptor tyrosin kinases. This binding stimulates erb3 and erb4 heterodimerization with erb2, promoting intrinsic kinase activity, which results in tyrosine phosphorylation. NRG1 isoforms act to induce the growth and differentiation of epithelial, neuronal, glial, and other types of cells.

Myoglobin is a member of the globin superfamily and can be found in skeletal and cardiac muscles. It is a haemoprotein that contributs to intracellular oxygen storage and transcellular facilitated diffusion of oxygen. Myoglobin has a single-chain globular structure of 153 amino acids, containing a heme prosthetic group (iron-containing porphyrin) in the core around which the remaining apoprotein folds. Myoglobin has 8 alpha helices and a hydrophobic core. Myoglobin’s molecular weight is 16.7 kDa, and it is the primary oxygen-carrying pigment of muscle tissues. The binding of oxygen in myoglobin is different from the cooperative oxygen binding in hemoglobin, since positive collaboration is a property of multimeric/oligomeric proteins only. Instead, the binding of oxygen by myoglobin is uninfluenced by the oxygen pressure in the surrounding tissue. Myoglobin is frequently referred to as having an "instant binding tenacity" to oxygen given its hyperbolic oxygen dissociation curve. Different organisms are able to hold their breaths longer due to high concentrations of myoglobin in their muscle cells. Myoglobin is responsible for the pigments that make meat red. The color of the meat is partly determined by the charge of the iron atom in myoglobin and the oxygen attached to it. Myoglobin is found in Type I muscle, Type II A and Type II B, but it is mostly deemed that myoglobin is not found in smooth muscle. Myoglobin is discharged from damaged muscle tissue (rhabdomyolysis), which contains very high concentrations of myoglobin. Even though the released myoglobin is filtered by the kidneys, it is toxic to the renal tubular epithelium and thus may cause acute renal failure.

Human immunodeficiency virus (HIV) is a retrovirusthat can lead to a condition in which the immune systembegins to fail, leading to opportunistic infections. HIV primarily infects vital cells in the humanimmune systemsuch as helper T cells(specifically CD4+ T cells), macrophagesand dendritic cells. HIV infection leads to low levels of CD4+ T cells through three main mechanisms: firstly, direct viral killing of infected cells; secondly, increased rates of apoptosisin infected cells; and thirdly, killing of infected CD4+ T cells by CD8 cytotoxic lymphocytesthat recognize infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunityis lost, and the body becomes progressively more susceptible to opportunistic infections. HIV was classified as a member of the genus Lentivirus, part of the family of Retroviridae. Lentiviruses have many common morphologies and biological properties. Many species are infected by lentiviruses, which are characteristically responsible for long-duration illnesses with a long incubation period. Lentiviruses are transmitted as single-stranded, positive-sense, enveloped RNA viruses. Upon entry of the target cell, the viral RNA genomeis converted to double-stranded DNAby a virally encoded reverse transcriptasethat is present in the virus particle. This viral DNA is then integrated into the cellular DNA by a virally encoded integraseso that the genome can be transcribed. Once the virus has infected the cell, two pathways are possible: either the virus becomes latentand the infected cell continues to function, or the virus becomes active and replicates, and a large number of virus particles are liberated that can then infect other cells.

ATF1, a cyclic-AMP dependent transcription factor, is expressed in a large selection of cell types and can dimerize with CREB. MSK1 and MSK2 protein kinases are essential for the stress-induced phosphorylation of transcription factors CREB and ATF1 in primary embryonic fibroblasts. Epidermal growth factor induction of c-jun expression needs ATF1 and MEF2 sites in the c-jun promoter.

PLAUR is one of 2 activators which convert the extracellular zymogen plasminogen to plasmin, a serine protease involved in a various normal and pathological processes that require cell migration and/or tissue destruction. PLAUR protein is synthesized and released from cells as a single-chain proenzyme with narrow enzymatic activity and is converted to an active two-chain disulfide-linked active enzyme by plasmin and other specific proteinases.

Resistin, a product of the RSTN gene, is a peptide hormone belongs to the class of cysteine-rich secreted proteins (monomeric peptide contains 11 cysteine residues) referred to as the RELM family, and is also described as ADSF (Adipose Tissue-Specific Secretory Factor) or FIZZ3 (Found in Inflammatory Zone 3). Resistin may be an important link between obesity. Mouse resistin, specifically produced and secreted by adipocyte, acts on skeletal muscle myocytes, hepatocytes and adipocytes themselves so that it reduces their sensitivity. Steppan et al. have suggested that resistin suppressed the ability to stimulate glucose uptake. They have also suggested that resistin was present at elevated levels in blood of obese mice, and was down regulated by fasting and by antidiabetic drugs. Way et al., on the other hand, have found that resistin expression is severely suppressed in obesity.
Other studies have shown that mouse resistin increases during the differentiation of adipocytes, but it also seems to inhibit adipogenesis. In contrast, the human adipogenic differentiation is likely to be associated with a down regulation of resistin gene expression.

Von Willebrand Factor A Domain Containing 2 (VWA2) is an extracellular matrix protein containing vWA-like domains. VWA2 contains a signal peptide sequence, an N-terminal VWA domain connected to 2 additional tandem vWA domains by a cysteine-rich sequence and an EGF-like domain. Also, another EGF-like domain is located at the C-terminus. Expression of VWA2 is induced in stage II, III and IV colon cancers and colon adenomas and is considered a novel serum marker for the diagnosis of early-stage colon cancer.

ACOT11 is a protein with acyl-CoA thioesterase activity towards medium (C12) and long-chain (C18) fatty acyl-CoA substrates. Expression of a similar murine protein in brown adipose tissue is induced by cold exposure and repressed by warmth. Expression of the mouse ACOT11 has been linked to obesity, with higher expression found in obesity-resistant mice compared with obesity-prone mice.

AICDA is an RNA-editing deaminase which belongs to the cytidine deaminase family. AICDA is involved in somatic hypermutation, gene conversion, and class-switch recombination of immunoglobulin genes. Defects in the AICDA gene are the cause of autosomal recessive hyper-IgM immunodeficiency syndrome type 2 (HIGM2).

Lanreotide is a peptide inhibitor of a number of endocrine, neuroendocrine, exocrine and paracrine functions. It shows good affinity for peripheral somatostatin receptors (anterior pituitary and pancreatic). In contrast, its affinity for central receptors is much lower. This profile confers a good specificity of action at the level of growth hormone and digestive hormone secretion. Lanreotide shows a much longer duration of action than natural somatostatin. In addition, its marked selectivity for the secretion of growth hormone, compared to that of insulin, makes it a suitable candidate for the treatment of acromegaly. By inhibiting the synthesis of thyroid stimulating hormone (TSH), lanreotide also normalised thyroid function of patients with thyrotrophin secreting adenomas in 50% (8/16) of the per-protocol population treated for 6 months. There was no significant reduction in the size of the adenoma. Furthermore, the inhibitory action of lanreotide on intestinal exocrine secretion, d

PC4 and SFRS1 Interacting Protein 1 (PSIP1) is a transcriptional coactivator involved in neuroepithelial stem cell differentiation and neurogenesis. PSIP1 is also involved particularly in lens epithelial cell gene regulation and stress responses. PSIP1 has a significant role in lens epithelial to fiber cell terminal differentiation. In addition, PSIP1 plays a protective role during stress-induced apoptosis. Furthermore, PSIP1 is a cellular cofactor for lentiviral integration.