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Lymphokine-activated killer T-cell-originated protein kinase (PBK) is a serine/threonine kinase related to the dual specific mitogen-activated protein kinase (MAPKK) family. PBK is abundant in placenta (is also found in the testis’ outer cell layer of seminiferous tubules) and absent from adult brain tissue. PBK is involved in the activation of lymphoid cells and supports testicular functions, with a possible role in the process of spermatogenesis. Mitotic phosphorylation is required for PBK’s catalytic activity. Once phosphorylated,PBK forms a complex with TP53, leading to TP53 destabilization and weakening of G2/M checkpoint during some kind of DNA damage. PBK is active only during mitosis. In addition, a PDZ domain in the tumor suppressor protein Dlg can coordinate with the T/SXV motif of PBK. PBK also phosphorylates MAP kinase p38, and may have a role in the activation of lymphoid cells.

Polymerase (DNA Directed), Epsilon 3, also know as POLE3, is a histone-fold protein which interacts with other histone-fold proteins to bind DNA in a sequence-independent manner. These histone-fold protein dimers merge into larger enzymatic complexes for DNA transcription, replication, and packaging.

Intracisternal A particle-promoted polypeptide (IPP) is a 66kDa protein (584 amino acids), which contains an N-terminal POZ protein-protein interaction domain and a C-terminal kelch repeat domain consisting of six tandem arranged repeats. The POZ domain (also called BTB domain) is present near the N-terminus of a fraction of zinc finger proteins and in protein that contain the pfam01344 motif such as kelch and pox virus proteins. The BTB/POZ domain mediates homomeric dimerization and in some instances heteromeric dimerization. POZ domains from several zinc finger proteins have been shown to mediate transcriptional repression and to interact with components of histone deacetylase co-repressor complexes including N-coR and SMRT.

ERP44 is an endoplasmic reticulum chaperone that takes part in thiol-dependent retention of the primary secretory pathway, forming mixed disulfides with substrate proteins through its conserved CRFS motif. ERP44 inhibits the calcium channel activity of ITPR1. ERP44 is involved in the control of oxidative protein folding in the endoplasmic reticulum.

GNB3 belongs to the WD repeat G protein beta family. GNB3 is an important regulator of alpha subunit, as well as of certain signal transduction receptor and effector. A single-nucleotide polymorphism (C825T) in GNB3 is linked with essential hypertension and obesity. In addition, this polymorphism is also linked with the occurrence of the splice variant GNB3-s, which seems to have increased activity. GNB3-s is an example of alternative splicing caused by a nucleotide change outside of the splice donor and acceptor sites. Further splice variants may exist for GNB3, however they have not been fully described. Among the diseases associated with GNB3 are syncope, and aortic coarctation.

Gamma-SNAP (NAPG) is a cytoplasmic protein which binds to a membrane receptor complex composed of VAMP, SNAP25 and syntaxin. NAPG mediates the membrane binding of NSF, which is crucial for membrane fusion reactions. NSF and SNAPs seem to be general components of the intracellular membrane fusion system, and their action at specific sites of fusion needs be controlled by SNAP receptors specific to the membranes being fused. NAPG mediates platelet exocytosis and controls the membrane fusion events of this process.

Signal-Regulatory Protein Alpha, SIRPA belongs to the signal-regulatory-protein (SIRP) family, as well as the immunoglobulin super family. The members of the SIRP family are receptor-type transmembrane glycoproteins which are involved in the negative regulation of receptor tyrosine kinase-coupled signaling processes.
SIRPA can be phosphorylated by tyrosine kinases. The phospho-tyrosine residues of this PTP have been shown to recruit SH2 domain containing tyrosine phosphatases (PTP), and perform as substrates of PTPs. SIRPA take part in signal transduction mediated by a variety of growth factor receptors. CD47 has been shown to be a ligand for SIRPA.

CHMP4A is a member of the SNF7 family and operates as chromatin-modifying protein. CHMP4A is a key component of the endosomal sorting vital for transport complex III (ESCRT-III) which takes part in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. Additionally, during HIV-1 infection, the virus utilizes the ESCRT-III complex to facilitate budding and exocytosis of viral proteins through the connection of CHMP4 and a protein engaged by HIV-1 p6, which exists in viral Gag assembly and budding. CHMP4A is expressed in higher quantities in skeletal muscle, kidney, liver and heart.

a-Synuclein (amino acids 1-140), an acidic neuronal protein of 140 amino acids, is extremely heat-resistant and is natively unfolded with an extended structure primarily composed of random coils. a-synuclein has been suggested to be implicated in the pathogenesis of Parkinson’s disease and related neurodegenerative disorders, and more recently, to be an important regulatory component of vesicular transport in neuronal cells. Moreover, recent studies have shown that a-synuclein has chaperone activity and that this activity is lost upon removing its C-terminal acidic tail (amino acids 96-140).

ARL15 is a member of the ARF family which are essential in eukaryotic vesicular trafficking pathways and have a vital part in the activation of phospholipase D. ARL15 variants influence levels of Acrp30, an adipocyte-derived protein that is extremely genetic and inversely related to the prospect of type 2 diabetes mellitus and coronary heart disease.

GABARAPL1 [Gamma-aminobutyric acid (GABA) receptor-associated protein-like 1] is a member of the MAP1 LC3 family. GABARAPL1 increases cell surface expression of kappa type opioid receptor through facilitating anterograde intracellular trafficking of the receptor.

FHIT is a member of the histidine triad gene family. FHIT gene encodes a diadenosine 5',5'''-P1,P3-triphosphate hydrolase involved in purine metabolism. FHIT gene includes the common fragile site FRA3B on chromosome 3, where carcinogen-induced damage can lead to translocations and abnormal transcripts of this gene. The FHIT protein is a tumor suppressor with reduced or no expression in numerous types of cancer. FHIT may also act as a tumor suppressor in normal cells. Alterations and deletions of the FHIT (Fragile Histidine Triad) gene are strongly linked to the genesis and establishment of human tumors of the lung, cervix, breast, colon, stomach, and pancreas. The expression of FHIT is more often lost in cancers of individuals with familial mutations causing deficiency in DNA repair genes such as BRCA1, BRCA2 and MSH2. In vitro FHIT functions as a hydrolase that cleaves diadenosine triphosphate (Ap3A) to ADP and AMP. The FHIT -Ap3A enzyme-substrate complex seems to be the tumor suppressor signal. The restoration of FHIT expression in FHIT -deficient cancer cells leads to apoptosis, involving the intrinsic caspase pathway, in cancer-derived cells and in tumor xenografts.

ST13 is an adaptor protein (co-chaperone) that mediates the association of HSP70 & HSP90 and appears in early receptor complexes. ST13 plays a role in the assembly process of glucocorticoid receptor, which requires the assistance of multiple molecular chaperones. The expression of ST13 is downregulated in colorectal carcinoma tissue signifying that is candidate tumor suppressor gene. Through common binding to both Hsp70 and Hsp90, ST13 functions as an adaptor that can integrate Hsp70 and Hsp90 interactions. The expression of ST13 decreases in colorectal cancer tissue compared with that in adjacent normal tissue. ST13 is mostly expressed in colorectal epithelia and adenocarcinoma cells. ST13 functions to promote the efficiency of glucocorticoid receptor maturation in cells. The expression levels of the ST13 gene were significantly decreased in primary tumors compared with adjacent mucosa.

FABP6 also called ileal fatty acid binding protein, is part of the small family of highly conserved, cytoplasmic proteins that bind long-chain fatty acids and other hydrophobic ligands. FABP6 cytosolic protein binds bile acid. FABP6 plays a role in fatty acid uptake, transport, and metabolism. FABP6 stimulates gastric acid and pepsinogen secretion. seems to be able to bind to bile salts and bilirubins.
FABP6 expression is restricted in the small intestine to the ileum where it is involved in the enterohepatic circulation of bile acids. Alternate transcription promoters generate 2 transcript variants, encoding a 128 aa and a 177 aa residue protein. Human FABP6 isoform 2 contains 128 amino acid residues and is acetylated on Ala2. FABP6 binds together fatty acids and bile acids and is directly involved in fatty acid transport and metabolism.

JAZF zinc finger 1 (JAZF1) is a nuclear protein with 3 C2H2-type zinc fingers, which functions as a transcriptional repressor. Chromosomal anomalies involving the JAZF1 are linked with endometrial stromal tumors. Alternatively spliced variants which encode different protein isoforms have been described; though, not all variants have been fully characterized.

Dysbindin domain-containing protein 2 (DBNDD2) is a member of the dysbindin family. DBNDD2 regulates the activity of casein kinase-1 and inhibits CSNK1D autophosphorylation (in vitro). DBNDD2 also interacts with CSNK1D and CSNK1E. DBNDD2 is detected in brain.

S100A13 is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 family members are localized in the cytoplasm and/or nucleus of a wide range of cells, and are involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. S100A13 is extensively expressed in various types of tissues with an elevated expression level in the thyroid gland. In smooth muscle cells, S100A13 co-expresses with other family members in the nucleus and in stress fibers, suggesting diverse functions in signal transduction.

SCG5 also called 7B2 protein is localized in neuroendocrine tissues. SCG5 functions as a chaperone protein for the proprotein convertase PC2 and is essential for the production of an active PC2 enzyme.

FABP12 is a member of the calycin superfamily and fatty-acid binding protein (FABP) family. The FABPs are a family of carrier proteins for fatty acids and other lipophilic substances for example eicosanoids and retinoids. These proteins are believed to enable the transfer of fatty acids between extra- and intracellular membranes. FABP12 has a role in lipid transport. FABP12 is expressed in several retinoblastoma cell lines. FABP12 has not been detected in fetal tissues.

Sarcoglycan Beta, also known as SGCB, is a part of the sarcoglycan family. SGCB belongs to the sarcoglycan complex which is a subcomplex of the dystrophin-glycoprotein complex that connects between the F-actin cytoskeleton and the extracellular matrix.

Ketosamine-3-kinase (FN3KRP) catalyzes the phosphorylation of psicosamines and ribulosamines compared to the adjacent gene which encodes a highly analogous enzyme, fructosamine-3-kinase that has different substrate specificity. The activity of both enzymes may cause deglycation of proteins to reinstate their function. A high concentration of glucose can result in non-enzymatic oxidation of proteins by reaction of glucose and lysine residues (glycation). The proteins altered in this way, are less active or functional.

MALD3 (a non-specific lipid transfer protein) is a major apple allergen. LTPs are found mainly in aerial plant organs such as leaves, seeds, flowers, and fruit. MALD3 is a heat-stable protein which is characterized by having resistance to pepsin hydrolysis.

TBCB is a member of the Microtubules family. Biosynthesis of functional microtubules include the involvement of a number of chaperones, termed Tubulin folding cofactors A (TBCA), B (TBCB), C (TBCC), D (TBCD) and E (TBCE), which operate on folding intermediates downstream of the cytosolic chaperon, known as TCP. The 244 amino acid cytoplasmic protein TBCB has one CAP-Gly domain and is universally expressed. TBCB takes part in the regulation of tubulin heterodimer dissociation and operates as a negative regulator of axonal growth.