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A 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.

The conserved 76 amino acid protein ubiquitin (Ub) regulates a host of intracellular processes through its enzymatic conjugation to other cellular proteins.
Ubiquitination occurs through sequential steps catalyzed by activating (E1), conjugating (E2), and ligase (E3) enzymes. The final step results in the formation of an isopeptide bond between Ub’s C-terminal glycine residue (G76) and a lysine residue of the target protein, although N-terminal ubiquitination is also known.
Outcomes of this modification include destabilization of the conjugated protein, altered protein trafficking and functional modulation.
After targeting the protein for specific localizations, ubiquitin is released from the substrate by deubiquitinating enzymes.
A mutant ubiquitin, having a Gly to Ala substitution at the C-terminus (G76A ubiquitin) supported several downstream reactions of the proteolytic pathway but inhibits the deubiquitination process.
As consequence, the Ub derivative becomes irreversibly conjugated to protein, shifting the equilibrium between the bound and unbound form in the direction of conjugation, at the expense of the free form.

The Argonaute protein is part of the RISC or RNA-induced silencing complex, as so, the protein has a key part in the slicing processes of RNA. The RNA interference (RNAi) is being held by RISC. Small non-coding RNA fragments bond to the Argonaute proteins, through base pairing, eventually leads to the cleavage of messenger RNA or translation suppression.

Decorin (DCN) is a small cellular or pericellular matrix proteoglycan which is closely related in structure to biglycan protein. Decorin is a secreted protein which binds to collagen and fibronectin in extracellular matrix. Decorin appears in different glycoforms, substituted with chondroitin sulfate or dermatan sulfate consistent with the original tissue. DCN contains one attached glycosaminoglycan chain. Decorin influences the rate of fibril formation. Decorin is capable of suppressing the growth of various tumor cell lines. DCN gene defects cause corneal dystrophy. The DCN gene is a candidate gene for Marfan syndrome.

BCL2 gene encodes an integral outer mitochondrial membrane protein that blocks the apoptotic death of some cells such as lymphocytes. Constitutive expression of BCL2, such as in the case of translocation of BCL2 to Ig heavy chain locus, is thought to be the cause of follicular lymphoma. Two transcript variants, produced by alternate splicing, differ in their C-terminal ends.

Thioredoxins are small disulphide-containing redox proteins (within the conserved Cys-Gly-Pro-Cys active site) that have been found in all the kingdoms of living organisms. Thioredoxin contains a single disulfide active site and serves as a general protein disulphide oxidoreductase. Thioredoxins are involved in the first unique step in DNA synthesis. It interacts with a broad range of proteins by a redox mechanism based on reversible oxidation of two cysteine thiol groups to a disulphide, accompanied by the transfer of two electrons and two protons. The net result is the covalent interconversion of a disulphide and a dithiol. Trx also provides control over a number of transcription factors affecting cell proliferation and death through a mechanism referred to as redox regulation. It has been suggested that thioredoxin may catalyze the formation of correct disulfides during protein folding because of its ability to act as an efficient oxidoreductant. This could be especially useful in

Caseine Kinase 1 alpha belongs is a member of the protein kinase superfamily, CK1 Ser/Thr protein kinase family, Casein kinase I subfamily. The CK1 isoforms - alpha, beta, gamma, delta, epsilon and their splice variants are involved in diverse cellular processes including membrane trafficking, circadian rhythm, cell cycle progression, chromosome segregation, apoptosis and cellular differentiation. Possibly CSNK1A1 can phosphorylate a large number of proteins and is involved in Wnt signaling where it phosphorylates CTNNB1 on Ser45. CSNK1A1 also interacts with the Axin complex.

Guanosine-3',5'-bis(diphosphate)-pyrophosphohydrolase MESH1 (HDDC3) contains an active site for ppGpp hydrolysis and a conserved His-Asp-box motif for Mn(2+) binding. In accordance with its structure, HDDC3 effectively catalyzes the hydrolysis of guanosine 3',5'-diphosphate (ppGpp) both in vitro and in vivo. In addition, HDDC3 suppresses SpoT-deficient lethality and RelA-induced delayed cell growth in bacteria.

SCG3 belongs to the chromogranin/secretogranin family of neuroendocrine secretory proteins. Though, the function of SCG3 is unknown, Granins operate as precursors for biologically active peptides. Several granins are known to serve as helper proteins in sorting and proteolytic processing of prohormones.

Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. Mitochondrial Ribosomal Protein S28, also known as MRPS28, is a protein coding gene which encodes a 28S subunit protein which is known as mitochondrial ribosomal protein S35.

N-acylneuraminate-9-phosphatase (NANP) belongs to the haloacid dehalogenase (HAD) family and is responsible for dephosphorylating N-acylneuraminate 9-phosphate to form N-acylneuraminate (N-acylneuraminate 9-phosphate + H2O = N-acylneuraminate + phosphate). The catalytic activity of NANP is relies on the presence of magnesium and is inhibited by vanadate and calcium, which is typical of the HAD phosphatase family.

Single-strand-selective monofunctional uracil-DNA glycosylase (SMUG1) is an enzyme responsible for recognizing base lesions in the genome and initiating base excision DNA repair. SMUG1 participates in base excision repair by removing uracil from single- and double-stranded DNA. SMUG1 serves as a monofunctional DNA glycosylase specific for uracil (U) residues in DNA and has inclination for single-stranded DNA substrates. SMUG1 activity is greater against mismatches (U/G) than against matches (U/A).

ATOX1 is a metal transport protein that is part of the ATX1 family. ATOX1 is a copper chaperone that takes part in cellular antioxidant defense and can bind and deliver cytosolic copper to the copper ATPase proteins in the trans-Golgi network for later incorporation to the ceruloplasmin. ATOX1 plays a role as an antioxidant against superoxide and hydrogen peroxide, and consequently, takes an important part in cancer carcinogenesis. Because of ATOX1 cytogenetic location, the gene can be a good a candidate gene for 5q-syndrome.

Bcl2 modifying factor, is a member of the Bcl2 protein family of apoptosis mediators. Bcl2 modifying factor is widely expressed in many tissues.
Bcl2 modifying factor contains a single Bcl2 homology domain 3 (BH3), and binds Bcl2 proteins and functions as an apoptotic activator. Also, Bcl2 modifying factor is important for histone deacetylase (HDAC) inhibitors which alters the balance between acetylation and deacetylation, significantly increasing histone acetylation, while strongly inducing apoptosis in a variety of cancer cell types. Bcl2 modifying factor supports Bim in regulating cell death processes in response to many stimuli. A synergistic role for bim and Bcl2 modifying factor in an apoptotic pathway leading to the clearance of Neisseria gonorrhoeae -infected cells.

ERGIC And Golgi 3, also known as ERGIC3 is a member of the ERGIC family and interacts with ERGIC1/ERGIC32. ERGIC3 takes part in the transport between endoplasmic reticulum and Golgi. One of the diseases which is associated with ERGIC3 is Breast Cancer.

PINK1 is a serine/threonine protein kinase which is found in the mitochondria. PINK1 shields cells from stress-induced mitochondrial dysfunction. Mutations results in one form of autosomal recessive early-onset Parkinson disease.

PRDX3 is part of the peroxiredoxin family of antioxidant enzymes, that reduces hydrogen peroxide and alkyl hydroperoxides. PRDX3 is particularly located in the mitochondria and involved in the regulation of cellular redox status by serving as a primary line of defense against H2O2 produced during respiration. PRDX3 is a significant regulator of the abundance of mitochondrial H(2)O(2), which itself promotes apoptosis in cooperation with other mediators of apoptotic signaling. PRDX3 mitochondrial protein is significantly decreased in Alzheimer Disease and Down Syndrome.

GIMAP6 is a member of the GTPases of immunity-associated proteins (GIMAP) family. GIMAP proteins contain GTP-binding and coiled-coil motifs, and may play roles in the regulation of cell survival. Decreased expression of this gene may play a role in non-small cell lung cancer. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene, which is found in a cluster with seven additional GIMAP genes on the long arm of chromosome 7.

The alteration of proteins with ubiquitin is a vital cellular mechanism for targeting atypical or short-lived proteins for degradation. Ubiquitination involves noT less than three classes of enzymes: ubiquitin-activating enzymes, or E1s, ubiquitin-conjugating enzymes, or E2s, and ubiquitin-protein ligases, or E3s. UBE2A is part of the E2 ubiquitin-conjugating enzyme family. UBE2A is necessary for post-replicative DNA damage repair. UBE2A catalyzes the covalent attachment of ubiquitin to other proteins. UBE2A is necessary for postreplication repair of UV-damaged DNA.

Protease Serine 7, also known as PRSS7, is in charge of initiating the activation of pancreatic proteolytic proenzymes such as trypsin, chymotrypsin and carboxypeptidase A. PRSS7 catalyzes the conversion of trypsinogen to trypsin which in turn activates other proenzymes including chymotrypsinogen, procarboxypeptidases, as well as proelastases.

Ubiquitin is a highly conserved 76 amino acid protein expressed in all eukariotes. Ub is found either in free form or conjugated to proteins as monomer or as chain of ubiquitin molecules. The most well characterized consequence of polyubiquitination is substrate degradation, while mono-ubiquitinated proteins are not degraded. Ubiquitin attachment to protein substrate is a complex process involving a ubiquitin activating enzyme (E1), a ubiquitin conjugating enzyme (E2) and a ubiquitin protein ligase (E3). The first ubiquitin moiety is transferred to the e-NH2 group of a Lys residue of the protein substrate to generate an isopeptide bond. In successive reactions, a poly ubiquitin chain is synthesized by processive transfer of additional activated moieties to Lys48 of the previously conjugated ubiquitin molecule. Ubiquitin K48R prevents the formation of poly ubiquitin chains via Lys48 linkages with mono ubiquitin molecules, avoiding the degradation of protein substrates.

FADD is an adaptor protein that cooperates with a variety of cell surface receptors and mediates cell apoptotic signals. Using its C-terminal death domain, FADD is recruited by TNFRSF6/Fas-receptor, tumor necrosis factor receptor, TNFRSF25, and TNFSF10/TRAIL-receptor, and consequently it take parts in the death signaling initiated by these receptors. FADD interaction with the receptors reviels the N-terminal effector domain of, which allows it to recruit caspase-8, and thus initiate the cysteine protease cascade. Knockout studies in mice furthermore propose the significance of FADD in premature T cell development. FADD plays a role in survival/proliferation and cell cycle development. FADD also takes part in cellular sublocalization, protein phosphorylation, and inhibitory molecules.

Matrix metalloproteinases are a family of zinc and calcium-dependent endopeptidases that break down extracellular matrix proteins. The MMP9 is secreted as a 92kDa zymogen. Cleavage of ProMMP-9 results in the active enzyme, having a molecular weight of approximately 82kDa. MMP9 is composed of the following domains: a gelatin-binding domain consisting of three fibronectin type II units, a catalytic domain containing the zinc-binding site, a proline-rich type V collagen-homologous domain and a hemopexin-like domain. MMP9 is produced by the several cell types: monocytes, macrophages, neutrophils, keratinocytes, fibroblasts, osteoclasts and endothelial cells. MMP9 is involved in inflammatory responses, tissue remodeling, wound healing, tumor growth and metastasis. MMP9 may also play an important part in local proteolysis of the extracellular matrix and in leukocyte migration, as well as in bone osteoclastic resorption. MMP9 cleaves type IV and type V collagens into large C-terminal three quarter fragments and shorter N-terminal one quarter fragments. MMP9 can also degrade fibronectin but not laminin or Pz-peptide.
MMP9 defects may be a cause of susceptibility to intervertebral disc disease (IDD), also known as lumbar disk herniation (LDH).

SBDS is part of an extremely preserved protein family which exists from archaea to vertebrates and plants. SBDS protein functions in RNA metabolism and has a role in the biogenesis of the 60S ribosomal subunit and translational activation of ribosomes. Shwachman-Diamond syndrome is a rare autosomal recessive disorder produced by mutations in the SBDS gene.