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Peptidyl-prolyl cis-trans isomerase FKBP1B (FKBP1B) belongs to the immunophilin protein family which has a role in immunoregulation and basic cellular processes involving protein folding and trafficking. FKBP1B is a cis-trans prolyl isomerase which binds the immunosuppressants FK506 and rapamycin. FKBP1B is extremely similar to the FK506-binding protein 1A. The physiological role of FKBP1B is thought to be in excitation-contraction coupling in cardiac muscle.

CHD4 is a member of a family of alleged chromodomain helicase-DNA-binding proteins. Biochemically, CHD4 is a component of the nucleosome transformation and deacetylase (NuRD) complex that takes part in transcription regulation. Autoantibodies targeting the CHD4 are a serologic feature of idiopathic inflammatory myopathies (IIM). In IIM Mi-2 antibodies are characterized by diagnostic sensitivity and specificity of approximately 4-18% and 98-100%, respectively. Moreover, anti-CHD4 antibodies are related to dermatomyositis (frequency up to 31%) and have a great positive predictive value for this type of disease subset. Anti-CHD4 are the only defined myositis-specific autoantibodies clearly focused to a nuclear target. An additional slightly outstanding feature of Mi-2 antibodies relates to their frequency in children, which is similar to that in adults.

Rab GDP dissociation inhibitor beta isoform 1 (GDI2) is a member of the GDP dissociation inhibitors (GDIs) family. GDI proteins can bind and release GDP-bound Rab proteins from membranes. GDI1 interacts with virtually all of the Rab proteins, whereas GDI2 interacts with Rabll but not Rab3A. GDI2 distributes ubiquitously, presenting a membrane bound location in perinuclear regions of cells.

Protein A is a cell wall component produced by several strains of Staphylococcus aureus. The recombinant Protein A is genetically engineered protein and holds 5 IgG-binding regions of protein A. Recombinant Protein A functions basically the same as native Protein A and is perfect for purification of polyclonal or monoclonal IgG antibodies. Protein A binds to human IgG1, IgG2 and IgG4, mouse IgG2a, IgG2b and IgG3 and rat IgG2c. Protein A also binds to total IgG from rabbit, pig, dog, cat, and guinea pig.

Crystallin, Mu (CRYM) is a taxon-specific crystallin protein which binds NADPH and has sequence similarity to bacterial ornithine cyclodeaminases. CRYM doesn’t perform a structural role in lens tissue; instead CRYM binds thyroid hormone for possible regulatory or developmental roles. CRYM gene mutations are linked with autosomal dominant non-syndromic deafness. CRYM specifically catalyzes the reduction of imine bonds in brain substrates which may include cystathionine ketamine and lanthionine ketamine.

CIB2 is a member of the calcium and integrin-binding family.CIB2 is possibly a Ca2+-binding regulatory protein which interacts with DNA-dependent protein kinase catalytic subunit (DNA-PKcs). In the skeletal muscle, CIB2 co-localizes with the integrin alpha7B subunit at the sarcolemma and at the neuromuscular and myotendinous junctions. CIB2 is closely related to CIB1.

CAMP Responsive Element Binding Protein 3-Like 2, also known as CREB3L2 belongs to the oasis bZIP transcription factor family. Members of this family are able to dimerize however from homodimers only. CREB3L2 is a transcriptional activator. Translocations between CREB3L2 on chromosome 7 and the gene fused in sarcoma on chromosome 16 can be found in some tumors. One disease which is associated with CREB3L2 is myxofibrosarcoma.

PCBP1 is a single-stranded nucleic acid binding protein that binds preferentially to oligo dC. PCBP1 plays a role in formation of a sequence-specific alpha-globin mRNP complex which is associated with alpha-globin mRNA stability. PCBP1 along with PCBP-2 and hnRNPK corresponds to the major cellular poly(rC)-binding protein. PCBP1 and PCBP-2 also functions as translational coactivators of poliovirus RNA via a sequence-specific interaction with stem-loop IV of the IRES and promotes poliovirus RNA replication by binding to its 5'-terminal cloverleaf structure.

Inhibitor of DNA Binding 2 (ID2) is a part of the inhibitor of DNA binding family, whose members are transcriptional regulators that contain a helix-loop-helix (HLH) domain but not a basic domain. Members of the ID family inhibit the functions of basic helix-loop-helix transcription factors in a dominant-negative way by suppressing their heterodimerization partners through the HLH domains. ID2 play a role in negatively regulating cell differentiation and may be an inhibitor of tissue-specific gene expression.

The La protein is a 47 kDa polypeptide that frequently acts as an autoantigen in systemic lupus erythematosus and Sjogren's syndrome patients. La is involved in various aspects of RNA metabolism, including binding and protecting 3-prime UUU(OH) elements of newly RNA polymerase III - transcribed RNA, processing 5-prime and 3-prime ends of pre-tRNA precursors, acting as an RNA chaperone, and binding viral RNAs linked to hepatitis C virus. It occurs in both the nucleus and the cytoplasm, where it assumes different roles. In the nucleus, La protein facilitates the production of tRNAs, acting as an RNA polymerase III (RNAP III) transcription factor by attaching to the U-rich 3'UTR of nascent transcripts, aiding in their folding and maturation. In the cytoplasm, La protein facilitates the translation of specific mRNAs, acting as a translation factor. As an RNA binding protein (RBP), La protein associates with subsets of mRNAs which contain a 5'-terminal oligopyrimidine (5'TOP) motif known to direct protein synthesis. The binding of La protein to particular classes of RNA molecules regulates their downstream processing, guards them from endonuclease digestion, and organizes their export from the nucleus. La/SS-B appears to be readily disposed to proteolysis, which results in many smaller (42kD, 320, and 270) nevertheless still immunoreactive polypeptides. La/SS-B antigen is strongly conserved across species. Anti-La/SS-B autoantibodies were originally found as precipitating autoantibodies in sera of Sjogren's Syndrome patients and referred to as SjT. Anti-La/SS-B precipitins are most frequently found in Sjogren's Syndrome, Systemic Lupus Erythematosus (SLE) and Subacute Cutaneous Lupus. Also, there seems to be a correlation between anti-La/SS-B and the absence of nephritis in SLE patients.

DnaK, originally identified for its DNA replication by bacteriophage l in E. coli is the bacterial hsp70 chaperone. This protein is involved in the folding and assembly of newly synthesized polypeptide chains and in preventing the aggregation of stress-denatured proteins.The protein coding region of the substrate binding domain of DnaK (amino acids 385-638) was amplified by PCR and cloned into an E. coli expression vector. The substrate binding domain of DNAK was purified to apparent homogeneity by using conventional column chromatography techniques. Additional amino acid (Met) is attached at N- terminus.

S100A8 is a part of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 proteins are localized in the cytoplasm and/or nucleus of a broad range of cells, and participate in the regulation of cellular processes such as cell cycle progression and differentiation. S100A8 plays a role in the inhibition of casein kinase and as a cytokine. S100A8 altered expression is related with cystic fibrosis disease. S100A8 is a calcium-binding protein that has antimicrobial activity against bacteria and fungi.S100A8 is crucial for resistance towards invasion by pathogenic bacteria. S100A8 up-regulates transcription of genes that are under the control of NF-kappa-B. S100A8 plays a role in the development of endotoxic shock in response to bacterial lipopolysaccharide. S100A8 endorses tubulin polymerization and promotes phagocyte migration and infiltration of granulocytes at sites of wounding. S100A8 takes part as a pro-inflammatory mediator in acute and chronic inflammation and up-regulates the release of IL8 and cell-surface expression of ICAM1.

CtBP was initially known as a cellular protein which cooperates with a C-terminal motif of adenovirus E1A oncoproteins. C-terminal-binding protein is extremely conserved in higher eukaryotes. Vertebrates hold two highly homologous CtBP proteins (CtBP1 and CtBP2) while invertebrates h a single CtBP. CtBP family proteins has a significant sequence homology with D-2-hydroxy acid dehydrogenases. In addition, CtBP proteins cooperates with numerous proteins and functions as a co-repressor of transcription.

EIF4EBP1 (eukaryotic translation initiation factor 4E-binding protein 1) belongs to a family of translation repressor proteins. EIF4EBP1 regulates eIF4E (eukaryotic translation initiation factor 4E) activity by preventing its assembly into the eIF4F complex and mediates the regulation of protein translation by hormones, growth factors and other stimuli that signal through the MAP kinase and mTORC1 pathways. EIF4EBP1 is phosphorylated in response to various signals including UV irradiation, resulting in its dissociation from eIF4E and activation of mRNA translation. EIF4EBP1 C-terminus has domains which control function and phosphorylation. EIF4EBP1 has a role in progression of breast neoplasms through cell signaling.

Dysbindin domain-containing protein 1 (DBNDD1) is a member of the dysbindin family.

HIV-1, the causative agent of acquired immunodeficiency syndrome (AIDS), contains an RNA genome which produces a chromosomally integrated DNA during the replicative cycle. Activation of HIV-1 gene expression by the transactivator Tat is dependent on an RNA regulatory element (TAR) located downstream of the transcription initiation site. TARDBP is a transcriptional repressor which binds to chromosomally integrated TAR DNA and represses HIV-1 transcription. In addition, TARDBP regulates alternate splicing of the CFTR gene. A similar pseudogene is present on chromosome 20.

Retinol Binding Protein-4 or RBP4, is the retinol currier protein in the plasma. RBP4 takes part on the conversion of retinol to the stable and soluble retinol complex in the plasma. RBP4 carries retinol from the liver tissue where its store to peripheral tissues. RBP-retinol complex has interactions with transthyretin in the plasma, thus prevents its loss by filtration in the kidney.

Retinol binding protein 4(RBP4) belongs to the lipocalin family and is the specific carrier for retinol (vitamin A alcohol) in the blood. This protein was found to be expressed and secreted by adipose tissue, and was strongly associated with insulin resistance. It delivers retinol from the liver stores to the peripheral tissues. In plasma, the RBP-retinol complex interacts with transthyretin which prevents its loss by filtration through the kidney glomeruli.
RBP4 delivers retinol from the liver to the peripheral tissues. In plasma, the rbp-retinol complex interacts with transthyretin, this prevents its loss by filtration through the kidney glomeruli.

MAD2L1-binding protein (MAD2L1BP) is a member of the MAD2L1BP family.MAD2L1BP is a binding protein of the MAD2 mitotic arrest deficient-like 1 (MAD2/MAD2L1). MAD2 is a fundamental factor of the spindle checkpoint which delays the onset of anaphase until all the kinetochores are connected to the spindle. The MAD2L1BP protein acts to curb the spindle checkpoint and allow mitosis to proceed through anaphase by binding MAD2L1 once it dissociated from the MAD2L1-CDC20 complex. For the duration of the cell cycle, MAD2L1BP levels increase and then remain constant until late mitosis after which they drop.

Nucleotide Binding Protein 2, also known as NUBP2 is an adenosine triphosphate (ATP) as well as metal-binding protein which is essential for the assembly of cyotosolic iron-sulfur proteins. NUBP2 performs in a heterotetramer with nucleotide-binding protein 1 (NUBP1). Moreover, alternative splicing results in multiple transcript variants have been found for NUBP2.

FK506 Binding Protein 5 (FKBP5) belongs to the immunophilin protein family, which has a role in immunoregulation and basic cellular processes involving protein folding and trafficking. FKBP5 is a cis-trans prolyl isomerase, which binds to the immunosuppressants FK506 and rapamycin. FKBP5 is an immunophilin protein with PPIase and co-chaperone activities. FKBP5 is assumed to mediate calcineurin inhibition. FKBP5 is a component of unligated steroid receptors heterocomplexes through interaction with heat-shock protein 90 (HSP90). In addition, FKBP5 interacts functionally with mature hetero-oligomeric progesterone receptor complexes along with the 90 kDa heat shock protein and P23 protein.

Ras GTPase-activating protein-binding protein 2 (G3BP2) is restricted to the plasma membrane and endocytic compartments and controls a fast endocytic recycling pathway. G3BP2 may be a scaffold protein which might be involved in mRNA transport.

GPN-loop GTPase 1 (GPN1) is a member of the GPN-loop GTPase family. GPN1 is a guanosine triphosphatase enzyme which has a role in DNA repair and may function in activation of transcription. Small GTPases, which share a biochemical mechanism, act as binary molecular switches and function in the cell is nucleocytoplasmic transport of both proteins and RNA. In addition, GPN1 establishs an interface between the RNA polymerase II enzyme and chaperone/scaffolding protein, proposing that it is essential to connect RNA polymerase II to regulators of protein complex formation. GPN1 may also be involved in nuclear localization of XPA.

Retinol-binding proteins (RBP) are a family of proteins with various functions. Retinol and retinoic acid play crucial roles in the modulation of gene expression and overall development of an embryo. However, deficit or excess of either one of these substances can cause early embryo mortality or developmental malformations. Regulation of transport and metabolism of retinol necessary for a successful pregnancy is accomplished via RBP. Retinol binding proteins have been identified within the uterus, embryo, and extraembryonic tissue of the bovine, ovine, and porcine, therefore RBP takes part in proper retinol exposure to the embryo and successful transport at the maternal-fetal interface.