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Pleiotrophin (Osteoblast-Specific Factor-1, OSF-1) contains 136 amino acid residues. The sequence is very rich in cationic amino acids (24% of the residues); lysine cluster sequences are found in the N-terminal and C-terminal ends of the structure.
The OSF-1 gene was shown by Northern blotting analysis to be expressed in mouse calvarial osteoblast-enriched cells and in mouse brain tissues, but not in thymus, spleen, kidney, liver, lung, testis or heart. Pleiotrophin has the ability to promote adhesion, migration, expansion, and differentiation of human osteoprogenitor cells. In addition to certain types of cancer, the embryonic growth and differentiation factor pleiotrophin is found also in adults in inflammatory diseases. In osteoarthritis, pleiotrophin is especially expressed in early stages, and its concentrations in the synovial fluid could serve as a marker for the progress of the disease. Pleitrophin might be involved in cartilage repair in osteoarthritis, in particular, in earlier stages.

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.

VAMP4 belongs to the synaptobrevin family who are involved in docking and/or fusion of vesicles with cell membrane. VAMP4 is enriched in the trans-Golgi network and may be a factor in the trans-Golgi network-to-endosome transport. VAMP4 is involved in the pathway which functions to eliminate an inhibitor (most likely synaptotagmin-4) of calcium-triggered exocytosis during the maturation of secretory granules. Synaptobrevins, syntaxins, and SNAP25 are the chief components of a protein complex involved in the docking and/or fusion of synaptic vesicles with the presynaptic membrane.

AMTN is a member of the amelotin family. AMTN is a lately discovered secreted enamel protein. AMTN mainly expressed during the maturation stage of enamel formation. AMTN gathers in a basal lamina-like structure at the interface between ameloblasts and enamel mineral and it co-localizes with one more lately described enamel protein, odontogenic ameloblast- related protein (ODAM(.

BTLA, also known as B & T Lymphocyte Associated, is an inhibitory molecule which is part of the Ig superfamily. BTLA is a type 1 transmembrane glycoprotein in the CD28 family of T cell costimulatory molecules. BTLA is a 3rd inhibitory receptor on T lymphocytes with resemblances to CTLA-4 & PD-1. Moreover, BTLA is a ligand for TNF (receptor) superfamily, TNFRSF14, and HVEM. BTLA-HVEM complexes negatively regulate T-cell immune responses.

C3b is derived from native C3 upon cleavage with the alternative pathway C3 convertase and release of C3a. C3b is essential to the function of all 3complement pathways. Initiation of each pathway generates proteolytic enzyme complexes (C3 convertases) which binds the target surface. These enzymes cleave a peptide bond in C3 releasing the anaphylatoxin C3a and activating C3b. Most of the C3b created during complement activation. Surface-bound C3b is needed in all 3 pathways for effective activation of C5 and formation of C5b-9 complexes which lyse the target cell membrane. Surface-bound C3b and its breakdown products iC3b and C3d are identifyid by various receptors on lymphoid and phagocytic cells which use the C3b ligand to stimulate antigen presentation to cells of the adaptive immune system. It results in an expansion of target-specific B-cell and T-cell populations.

Gametocyte Specific Factor 1 (GTSF1) is a member of the UPF0224 (FAM112) family and contains 1 CHHC-type zinc finger. A key paralog of the GTSF1 gene is GTSF1L.

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.

TRAPPC3 is a part of the TRAPP complex that takes part in connection of transport vesicles to the cis-Golgi membrane. Additionally, TRAPPC3 is involved in vesicular transport from endoplasmic reticulum to Golgi.

S100A6 is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. S100 proteins are involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21.
S100A6 may function in stimulation of Ca2+-dependent insulin release, stimulation of prolactin secretion, and exocytosis. Chromosomal rearrangements and altered expression of the S100A6 gene are implicated in melanoma.

EPH Receptor A2 (EPHA2) is a member of the ephrin receptor subfamily of the protein-tyrosine kinase family. EPHA2 is a protein which binds ephrin-A ligands. EPH and EPH-related receptors are associated with mediating developmental events, particularly in the nervous system. Receptors in the EPH subfamily normally have a single kinase domain and an extracellular region containing a Cys-rich domain and 2 fibronectin type III repeats. The ephrin receptors are divided into two groups based on the similarity of their extracellular domain sequences and their affinities for binding ephrin-A and ephrin-B ligands. EPHA2 gene mutations are the cause of certain genetically-related cataract disorders.

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.

The Sec61 complex is the key component of the protein translocation apparatus of the ER (endoplasmic reticulum) membrane. Oligomers of the Sec61 complex construct a transmembrane channel where proteins are translocated across and incorporated into the ER membrane. This complex consists of 3 membrane proteins- alpha, beta, and gamma. The SEC61B gene encodes the beta-subunit protein. The Sec61 subunits are also detected in the post-ER compartment, suggesting that these proteins can get out of the ER and recycle back.

Macrophage Inflammatory Proteins (MIP) 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 officially named CCL3 and CCL4 respectively. Both are major factors produced by macrophages after they are stimulated with bacterial endotoxins. They activate human granulocytes (neutrophils, eosinophilsand basophils) which can lead to acute neutrophilic inflammation. They also induce the synthesis and release of other pro-inflammatory cytokines such as interleukin 1 (IL-1), IL-6 and TNF-a from fibroblasts and macrophages. The genes for CCL3 and CCL4 are both located on human chromosome 17.

Pirin (PIR) which belongs to the cupin superfamily, is an Fe(II)-containing nuclear protein expressed in all tissues of the body and concentrated within dot-like subnuclear structures. Pirin may function as a transcriptional cofactor and is involved in the regulation of DNA transcription and replication, as a result of interactions with nuclear factor I/CCAAT box transcription factor as well as B cell lymphoma 3-encoded oncoprotein.

RUVBL1 is part of NuA4 histone acetyltransferase complex which participates in transcriptional activation of specific genes mainly by acetylation of nucleosomal histone H4 and H2A. This complex is essential for the activation of transcriptional programs associated with oncogene and proto oncogene mediated growth induction, tumor suppressor mediated growth arrest.

LASP1 has a vital part in the regulation of dynamic actin-based, cytoskeletal activities. Agonist-dependent changes in LASP1 phosphorylation can additionally assist in regulation of actin-associated ion transport activities in the parietal cell and in several other F-actin-rich secretory epithelial cell types.

KIT, also known as KIT Proto-Oncogene Receptor Tyrosine, is a cytokine receptor which is expressed not only in hematopoietic stem cells but likewise in other cell types. KIT binds to receptor tyrosine kinase type III, which is a stem cell factor, also named a "rigid factor" or "c-kit ligand". Once this receptor binds to stem cell factor (SCF), it forms a dimer which activates intrinsic tyrosine kinase activity, which sequentially phosphorylates & activates signaling molecules which breed signals in cells. This receptor protects vascular smooth muscle cells from apoptosis in addition to restoring cardiac function after myocardial infarction.

Alpha-hemoglobin stabilizing protein (AHSP) is an erythroid-specific protein that acts as a chaperone to prevent the aggregation of A-hemoglobin during normal erythroid cell development. AHSP specifically protects free A-hemoglobin from precipitation in live cells and in solution. AHSP is expected to modulate pathological states of alpha-hemoglobin excess such as beta-thalassemia. Furthermore, AHSP promotes alpha globin chain stability in human erythropoiesis. In addition, the AHSP stabilizes the alpha-Hb chain, thus avoiding its precipitation and its ability to generate ROS, which is implicated in cell death. AHSP is expressed in blood and bone marrow. AHSP subunit is a monomer, it forms a heterodimer with free alpha-hemoglobin. On the other hand, AHSP does not bind beta-hemoglobin nor alpha2beta2 hemoglobin A. AHSP is downregulated in TSEs (transmissible spongiform encephalopathies).

Babesiosis is a disease caused by apicomplexan parasites of the Babesia genus. The Babesia microti life cycle involves 2 hosts, which include a rodent, mainly the white-footed mouse (Peromyscus leucopus) and a tick in the Ixodes genus. During a blood meal, a Babesia-infected tick introduces sporozoites into the mouse host. Sporozoites pass into the erythrocytes and undergo asexual reproduction (budding). In the blood, some parasites differentiate into male and female gametes, though these cannot be distinguished by light microscopy. The definitive host is the tick. Once ingested by an proper tick, gametes unite and undergo a sporogonic cycle resulting in sporozoites. Transovarial transmission (aka vertical or hereditary transmission) has been detected for "large" Babesia species but not for the "small" Babesia, such as B. microti. Humans enter the cycle when bitten by the infected ticks. Thus during a blood meal, a Babesia-infected tick introduces sporozoites into the human host. Sporozoites then enter erythrocytes and undergo asexual replication (budding). Multiplication of the blood-stage parasites is responsible for the clinical manifestations of the disease. Humans typically are dead-end hosts. However, human-to-human transmission is well acknowledged to occur via contaminated blood transfusions.

Cytoplasmic Polyadenylation Element Binding Protein 1 (CPEB1) belongs to the cytoplasmic polyadenylation element (CPE) binding protein family, whose members regulate translation of cyclin B1 during embryonic cell divisions. The CPEB1 is a highly conserved protein which binds to a specific RNA sequence called the CPE found in the 3' UTR of some mRNAs. Analogous proteins in Xenopus and mouse function to stimulate cytoplasmic polyadenylation of dormant mRNAs with short polyA tails, resulting in their translation.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is wilyde 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.

CRP is an acute phase protein that correlates with inflammatory disease and is synthesized by hepatocytes during the acute phase response by certain cytokines (IL-1 and TNF Alpha and Beta). CRP levels increase dramatically ( up to 1,000 fold) and serve as a useful marker of inflammation in such conditions as bacterial infection, rheumatoid arthritis, viral infections, transplantation rejection, meningitis, myocardial infarction, septicemia, osteomyelitis and others. CRP is also highly correlated to Serum Amyloid A levels.

UL16 Binding Protein 3 (ULBP3) is a ligand for the NKG2D receptor in NK cells. ULBPs activate different signaling pathways resulting in the production of cytokines and chemokines. ULBP3 is a ligand for the KLRK1/NKG2D receptor, along with at least ULBP1 and ULBP2. Binding of ULBPs ligands to KLRK1/NKG2D stimulates calcium mobilization and activation of the JAK2, STAT5, ERK and PI3K kinase/Akt signal transduction pathway. ULBP3 has lower affinity for KLRK1/NKG2D compared to ULBP1 and ULBP2 and stimulates weaker signaling responses than does ULBP2 or ULBP1.