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GrpE , co-chaperone of E.coli, participates actively in the response to hyperosomotic and heat shock by preventing the aggregation of stress-denatured proteins in association with DnaK. This protein is the nucleotide exchange factor for DnaK and may function as a thermosensor. Several rounds of ATP-dependent interactions between DnaJ, DnaK and GrpE are required for fully efficient folding.

XRCC2 belongs to the RecA/Rad51-related protein family which takes part in homologous recombination to repair DNA damage and preserve chromosome stability. XRCC2 gene participates in the mending of DNA double-strand disruptions by homologous recombination. Additionally, XRCC2 functionally complements Chinese hamster irs1, a repair-deficient mutant which displays hypersensitivity to diverse DNA-damaging agents.

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.

CHMP2B is a member of the vacuolar sorting protein family. CHMP2B is a component of the ESCRT-III complex which is essential for sorting endosomal articles into multivesicular bodies (MVBs), and are also obligatory for the formation of these bodies. CHMP2B is usually found in brain, heart, skeletal muscle, small intestine, pancreas, lung, placenta and leukocytes.

DsbE is a reducing Dsb protein involved in electron transfer for cytochrome c maturation in the periplasm of Escherichia coli. DsbE is one of 12 proteins required for their assembly in the periplasm. DsbE functions is to decrease disulphide bonds formed among correctly paired cysteine residues in the cytochrome c apoproteins prior to haem attachment by CcmF and CcmH.

HNRNPC is a member of the subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs) which are related to pre mRNAs in the nucleus and effect pre mRNA processing and other aspects of mRNA metabolism and transport. Although all of the hnRNPs are present in the nucleus, several hnRNPs travel between the nucleus and the cytoplasm. The hnRNP proteins have specific nucleic acid binding properties.

Chemokine (C-X-C motif) ligand (CXCL7) is a small cytokine belonging to the CXC chemokine family. It is a protein that is released in large amounts from platelets following their activation. It stimulates various processes including mitogenesis, synthesis of extracellular matrix, glucose metabolism and synthesis of plasminogen activator.

SLAMF1 is a member of the immunoglobulin gene superfamily and is involved in T-cell stimulation. The SLAMF1 protein is constitutively expressed on peripheral blood memory T cells, T-cell clones, immature thymocytes, and a fraction of B cells, and is swiftly induced on naive T cells after activation. There are probably 2 modes of SLAM signaling: one in which the inhibitor SH2D1A serves as a negative regulator and another in which protein-tyrosine phosphatase 2C (PTPN11)-dependent signal transduction functions.

The protein encoded by this gene is a member of the bone morphogenetic protein family which is part of the transforming growth factor-beta superfamily. The superfamily includes large families of growth and differentiation factors. Bone morphogenetic proteins were originally identified by an ability of demineralized bone extract to induce endochondral osteogenesis in vivo in an extraskeletal site. This particular family member plays an important role in the onset of endochondral bone formation in humans, and a reduction in expression has been associated with a variety of bone diseases, including the heritable disorder Fibrodysplasia Ossificans Progressiva. Alternative splicing in the 5' untranslated region of this gene has been described and three variants are described, all encoding an identical protein.

43 kDa receptor-associated protein of the synapse (RAPSN), is expressed in the postsynaptic membrane of skeletal muscle. RAPSN is essential for the clustering of nicotinic acetylcholine receptors (nAChR). In addition RAPSN self-associates via at least two of its seven tetra-tricopeptide repeats (TPRs). RAPSN interacts with the large intracellular domain of the nAChR a subunit all the way through the hydrophobic surface of the coiled-coil domain. RAPSN modifies trafficking of AChR within the cell. Overexpression inhibits agrin-induced AChR clustering pathway. RAPSN also plays a role in postsynaptic congenital myasthenic syndromes.

SMNDC1 is a vital splicing factor obligatory for spliceosome assembly which is a part of the SMN family. SMNDC1 has one Tudor domain with significant similarity to Survival Motor Neuron (SMN) and is expressed in heart, pancreas and skeletal muscle, localizing to Cajal bodies and nuclear speckles. Mutations in SMNDC1 are cause of autosomal recessive proximal spinal muscular atrophy.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is widely used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin-streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH.

SH3 domain-binding glutamic acid-rich-like protein (SH3BGRL) belongs to the human SH3BGR family. SH3BGRL gene which is located to chromosome Xq13.3, encodes a small protein of 114 amino acids that is extensively expressed in various tissues including liver and blood. SH3BGRL protein contains a prolinerich sequence (PLPPQIF), which is comprsed of both the SH3 binding (PXXP)3 and the Homer EVH1 binding (PPXXF)4 motif.

Listeriolysin O (aka LLO) is a hemolysin produced by Listeria monocytogenes bacteria, the pathogen responsible for causing listeriosis. The toxin may be regarded as a virulence factor, since it is crucial for the virulence of L. monocytogenes. LLO is a single polypeptide protein encoded by the hlyA gene and composed of 529 residues. LLO is a thiol-activated cholesterol-dependent pore forming toxin protein; therefore, it is activated by reducing agents and inhibited by oxidizing agents. Still, LLO differs from other thiol-activated toxins, as its cytolytic activity is maximized at a pH of 5.5. Inside the acidic phagosomes (average pH ~ 5.9) of cells that have phagocytosed L. monocytogenes, LLO is selectively activated by maximizing activity at a pH of 5.5. Following the phagosome lysis by LLO, the bacterium breaks out into the cytosol, where it is able to grow intracellularly, and the toxin has reduced activity in the more basic cytosol. Thus, LLO permits L. monocytogenes to break out from the phagosomes into the cytosol without harming the plasma membrane of the infected cell, which allows the bacteria to live intracellularly, where they are sheltered from extracellular immune system factors such as the complement system and antibodies. LLO also brings about dephosphorylation of histone H3 and deacetylation of histone H4 in the early phases of infection, before entry of L. monocytogenes into the host cell. The pore-forming activity is not implicated in causing the histone modifications. The modifications of the histones affect the down regulation of genes encoding proteins involved in the inflammatory response. Therefore, LLO may be significant in subverting the host immune response to L. monocytogenes. At its NH2-terminus it possesses a 25 residues long typical signal sequence excited during the secretion process. Moreover, in its NH2-terminus there is also a 19 amino acids PEST- like sequence that may target this toxin for degradation. The PEST-like sequence found in LLO and is considered crucial for virulence, given that mutants lacking the sequence lysed the host cell. Nevertheless, contrary to PEST's supposed role in protein degradation, evidence implies that the PEST-like sequence may control LLO production in the cytosol rather than increase degradation of LLO.

Adipocyte fatty acid binding protein FABP4 is a 15 kDa member of the intracellular fatty acid binding protein (FABP) family, which is known for the ability to bind fatty acids and related compounds (bile acids or retinoids) in an internal cavity. FABP4 is expressed in a differentiation-dependent fashion in adipocytes and is a critical gene in the regulation of the biological function of these cells.
In mice, targeted mutations in FABP4 provide significant protection from hyperinsulinemia and insulin resistance in the context of both dietary and genetic obesity. Adipocytes obtained from FABP4-deficient mice also have reduced efficiency of ipolysis in vitro and in vivo, and these mice exhibited moderately improved systemic dyslipidemia. Recent studies also demonstrated FABP4 expression in macrophages upon differentiation and activation. In these cells, FABP4 modulates inflammatory responses and cholesterol ester accumulation, and total or macrophage-specific FABP4 deficiency confers dramatic protection against atherosclerosis in the apoE-/- mice. These results indicate a central role for FABP4 in the development of major components of the metabolic syndrome through its distinct actions in adipocytes and macrophages.

Growth arrest and DNA Damage-Inducible Protein (GADD45A) binds both Cdks and PCNA. GADD45A is involved in DNA replication and repair. GADD45A stimulates DNA excision repair in vitro and inhibits entry of cells into S phase. GADD45A may serve as a link between p53-dependent cell cycle checkpoint and DNA repair. The GADD45A gene belongs to a group of genes whose transcript levels are increased following stressful growth arrest conditions and treatment with DNA-damaging agents. GADD45A responds to environmental stresses by mediating activation of the p38/JNK pathway via MTK1/MEKK4 kinase. GADD45A binds to proliferating cell nuclear antigen.

Bromodomain Containing 2, also known as BRD2 is a transcriptional regulator which is a member of the BET, bromodomains and extra terminaldomain, family of roteins. BRD2 links with transcription complexes and it acetylated chromatin in the course of mitosis, and it selectively binds o the acetylated lysine-12 residue of histone H4 through its two romodomains. BRD2 maps to the major histocompatability complex MHC) class II region on chromosome 6p21.3, however sequencecomparison advocate that the protein is not implicated in the immune response. BRD2 has been implicated injuvenile myoclonic epilepsy, a common form of epilepsy which grows to be visible in adolescence.

Major histocompatibility complex, class II, DR alpha (HLA-DRA) belongs to the MHC class II family. HLA-DRA binds peptides derived from antigens which access the endocytic route of antigen presenting cells (APC) and presents them on the cell surface for identification by the CD4 T-cells. The peptide binding cleft accommodates peptides of 10-30 residues. The peptides presented by MHC class II molecules are generated mainly by degradation of proteins which access the endocytic route, where they are processed by lysosomal proteases and other hydrolases.

Plasma protease C1 inhibitor (SERPING1) is a part of the serpin superfamily of serine protease inhibitors. SERPING1 plays an important role in regulating activation of both the complement and contact systems. That isdue to the fact that SERPING1 regulates the activation of complement factor C1 in addition to the activity of activated C1 by coupling with the active catalytic site at the light chains of C1r and C1s. SERPING1 insufficiency results in hereditary angioedema, which is characterized by recurrent episodes of localized angioedema of the skin, gastrointestinal mucosa or upper respiratory mucosa.

ADP-ribosylation factor 5 (ARF5) is a small guanine nucleotide-binding protein which enhances the enzymatic activities of cholera toxin. ARF-dependent regulatory mechanisms include the coordination of spectrin interactions with golgi membranes and the connection of actin to the golgi via rho family-dependent G-protein localization and WASP/Arp2/3 complexes. ARF5 is involved in vesicular transport and functioning via phospholipase D activation.

UNC-5 Netrin Receptor B or UNC5B, is part of the UNC5 family that has 4 linked receptors and act as a axon guidance molecule Netrin-1 receptor. UNC5B promotes inhibitionleukocyte migration, capillary branching and osteoclast differentiation that are Netrin-1-mediated. UNC5B is responsible for the activation of DAPK1 that can cause apoptosis. The protein takes part in tumorgenesis, development of atherosclerosis and tubular epithelial cells survival when an acute injury in the kidney occurs.

DYNLL1 is a protein that cooperates with NOS1 causing NOS1 inhibition. Binding of DYNLL1 weakens NOS1 (Neuronal nitric oxide synthase) dimer, a conformation needed for activity, and it regulates several biologic processes through its effects on nitric oxide synthase activity. DYNLL1 is a ubiquitously expressed protein that demonstrates high expression in testis and moderate expression in brain.

IGFBP6 plays a role in lipoprotein assembly and dietary cholesterol absorption. in addition to its acyltransferase activity, it may act as a ligase. may provide cholesteryl esters for lipoprotein secretion from hepatocytes and intestinal mucosa.