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Thyroglobulin (TG) represents one of the main autoantigenic targets in autoimmune thyroid disease of humans. TG is a large globular dimeric glycoprotein with a total molecular weight of 660 kDa, which occupies a key precursor role in the biosynthesis of the thyroid hormones. Approximately 75% of the total protein content of the thyroid follicle consists of TG. The thyroid gland uses the Thyroglobulin in order to produce the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroglobulin is produced by the thyroid epithelial cells (thyrocytes) which form spherical follicles. Thyroglobulin is subsequently secreted and stored in the follicular lumen.
Patients with Hashimoto's thyroiditis or Graves' disease, frequently develop antibodies against Thyroglobulin. Tg-specific antibodies help in the diagnosis of the above diseases, however they also may be present in apparently healthy euthyroid individuals. Blood Thyroglobulin levels can be used as a tumor marker for certain kinds of thyroid cancer, and the may also be elevated in cases of Graves' disease.

Plasminogen Activator Inhibitor-2 (Serpine2) which inhibits thrombin, plasmin and plasminogen activators is a part of the Serpin superfamily of the serine protease inhibitors. Serpine2 is able to transform human embryonic kidney cells into neuron-like cells. Furthermore, Serpine2's over expression in mice leads to progressive neuronal and motor dysfunction.

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.

KPNA2 belongs to the karyopherin alpha family. KPNA2 has a vital part in the nuclear import of proteins with a conventional nuclear localization signal (NLS).
In vitro, KPNA2 bound specifically and directly to substrates having a simple or bipartite NLS motif. KPNA2 stimulated docking of import substrates to the nuclear envelope and together with Ran reconstituted complete nuclear protein import.

Synaptojanin 2 Binding Protein (SYNJ2BP) contains 1 PDZ (DHR) domain which binds to isoform 2A of SYNJ2 (through the unique motif in the C-terminus) and interacts with MAPK12.

PFN4 is a small actin-binding protein that participates in the dynamic turnover and restructuring of the actin cytoskeleton. PFN4 is localized in all eukaryotic organisms in the majority of cells. PFN4 is crucial for spatially and temporally controlled growth of actin microfilaments, which is a necessary process in cellular locomotion and cell shape changes.

Thiamin pyrophosphokinase 1 (TPK1) is a homodimer which catalyzes the phosphorylation of thiamine to thiamine pyrophosphate. TPK1 is found in the heart, kidney, testis, small intestine and peripheral blood leukocytes, and at very low levels in a variety of tissues. TPK1 gene defects cause the thiamine metabolism dysfunction syndrome type 5, episodic encephalopathy type (THMD5), which is an autosomal recessive metabolic disorder due to an inborn error of thiamine metabolism.

PTHrP is a powerful and discriminating agonist of PTH2R which takes part in adenyl cyclase activation and intracellular calcium levels elevation. PTHrP encourages protein kinase C beta activation, recruitment of beta-arrestin and PTH2R internalization. Additionally, PTHrP inhibits cell proliferation through its contribution to PTH2R activation, activates nociceptors and nociceptive circuits and acts as a neuropeptide in spermatogenesis.

Meteorin (METRN) is involved in both glial cell differentiation and axonal network formation during neurogenesis. METRN promotes astrocyte differentiation and transforms cerebellar astrocytes into radial glia. Moreover, the METRN protein stimulates axonal extension in small and intermediate neurons of sensory ganglia by activating nearby satellite glia.

Inositol monophosphatase 3 (IMPAD1) belongs to the inositol monophosphatase family. IMPAD1 is restricted to the Golgi apparatus and catalyzes the hydrolysis of phosphoadenosine phosphate (PAP) to adenosine monophosphate (AMP). IMPAD1 gene mutations cause the GRAPP type chondrodysplasia with joint dislocations, and a pseudogene of the IMPAD1 gene is located on the long arm of chromosome 1.

Small nuclear ribonucleoprotein complexes (abbreviated as U-snRNP) are essential for splicing of precursor mRNA molecules. U1-snRNP is the most abundant RNP particle in the nucleus and consists of one small uridylate-rich RNA (U1 RNA) complexed with several proteins: the three 68/70 kDa, A, C polypeptides are unique to the U1-snRNP particle, whereas 7 so-called Sm proteins (B/B', D1, D2, D3, E, F, G) form a core subparticle that is common to all U-snRNP complexes.
Both the U1-specific proteins and the Sm core particle are targets of autoantibodies which classically have been called the RNP and RNP-Sm specificities, respectively. A clean diagnostic distinction of these specificities has been complicated by the biochemical difficulties of producing clean subparticle fractions from native sources. The use of single recombinant proteins as antigenic targets guarantees a much higher sensitivity and specificity and is the only way to determine RNP antibodies sensu stricto without the disturbing influence of Sm antigens; also with single U1 proteins antibodies will be detected which can be missed because of steric hindrance when using the RNP-Sm complex in an assay.
Autoantibodies to U1-snRNP are present in 95% of patients with Mixed Connective Tissue Disease (MCTD) and 30% of patients with SLE. Antibodies against the 68/70 kDa protein are known to have a high clinical significance in MCTD patients. The 68/70 kDa nomenclature of this protein refers to the fact that different splice variants of the protein are found in human cells.

Small VCP/p97-interacting protein (SVIP) is involved in various cellular processes, including membrane fusion and ubiquitin-dependent protein degradation. SVIP functions as an inhibitor of the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. On the other hand, SVIP overexpression increased the levels of p62 protein and enhanced starvation-activated autophagy as well as stimulated sequestration of polyubiquitinated proteins and p62 in autophagosomes.

Prefoldin subunit 2 (PFDN2) belongs to the prefoldin beta subunit family. The PFDN2 protein is one of 6 subunits of prefoldin, which is a molecular chaperone complex that binds and stabilizes newly synthesized polypeptides, thus allowing them to fold correctly. PFDN2 binds specifically to cytosolic chaperonin (c-CPN) and transfers target proteins to it. PFDN2 also binds to a nascent polypeptide chain and promotes folding in an setting in which there are many competing pathways for nonnative proteins.

Inositol monophosphatase 3 (IMPAD1) belongs to the inositol monophosphatase family. IMPAD1 is restricted to the Golgi apparatus and catalyzes the hydrolysis of phosphoadenosine phosphate (PAP) to adenosine monophosphate (AMP). IMPAD1 gene mutations cause the GRAPP type chondrodysplasia with joint dislocations, and a pseudogene of the IMPAD1 gene is located on the long arm of chromosome 1.

Protein phosphatase 1 regulatory subunit 11 (PPP1R11) is located within the major histocompatibility complex class I region on chromosome 6 and is expressed in a variety of both adult and embryonic tissues. PPP1R11 acts as an inhibitor of PP1 (protein phosphatase 1), particularly showing a sensitivity toward the metal-independent and metal-dependent forms of PP1. Deletion of a portion of the q arm of chromosome 6 is related with early onset intestinal cancer, proposing the presence of a cancer vulnerability locus.

Glycophorins A & B (GYPA &GYPB) are the main sialoglycoproteins of the human erythrocyte membrane which carry the antigenic determinants for the MN and Ss blood groups. Along with the M or N and S or s antigens which normally occur in all populations, approximately 40 related variant phenotypes were identified. These variants comprise all the variants of the Miltenberger complex and some isoforms of Sta, as well as Dantu, Sat, He, Mg, and deletion variants Ena, S-s-U- and Mk. GYPA is significant for the function of SLC4A1 and is necessary for high activity of SLC4A1. GYPA is involved in translocation of SLC4A1 to the plasma membrane. GYPA is also a receptor for: the influenza virus, Plasmodium falciparum erythrocyte-binding antigen 175 (EBA-175); binding of EBA-175 is dependent on sialic acid residues of the O-linked glycans and is also a receptor for Hepatitis A virus (HAV).

Hyaluronan And Proteoglycan Link Protein 1, which is also known as HAPLN1 is a part of the HAPLN family.HAPLN1 contains one Ig-like V-type domain and two Link domains. In the extracellular cartilage matrix, HAPLN1 stabilizes the aggregates of proteoglycan monomers by means of hyaluronic acid .

RPL22, a cytoplasmic ribosomal protein, is a member of the L22E family of ribosomal proteins and a component of the 60S subunit. RPL22 binds specifically to Epstein-Barr virus-encoded RNAs (EBERs) 1 and 2.

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 interferons.

Trypsin inhibitor SPINK1 is secreted from pancreatic acinar cells into pancreatic fluid. SPINK1 has a role in inhibition of trypsin-catalyzed premature initiation of zymogens in the pancreas and the pancreatic duct. Alterations in SPINK1 gene are the cause for tropical calcific and pancreatitis hereditary pancreatitis.

Olfactory marker protein (OMP) which is expressed in the cytoplasm of olfactory chemosensory neurons in the nasal neuroepithelium, is associated in a unique way with the mature olfactory receptor neurons in numerous vertebrate species. OMP have a modulatory part in the odor detection/signal transduction cascade ant its expression is a sign of mature vertebrate olfactory receptor neurons (ORNs). OMP is also a potent enhancer of mitosis in fetal olfactory epithelial cells and it promotes an increase in uptake of tritiated thymidine in liver.

TAGLN3 holds a putative Actin-binding domain, two potential phosphorylation sites, two EF-hand motifs and a calponin-homology (CH) domain. TAGLN3 is homologic to transgelin and calponin, two cytoskeleton-interacting proteins. TAGLN3 is a member of the calponin family, and is co-localized with Actin and tubulin, which indicates that TAGLN3 has a part in neuronal plasticity or as a signaling protein. As a result of a wide-ranging expression pattern, TAGLN3 is able to take different roles in the developing and adult brain.