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Epidermal growth factor receptor or EGFR or Erb-1 is a membranal protein that acts as a receptor for the extracellular EGF proteins family. This protein is a part of a family of receptors called ErbB family which are all tyrosine kinases receptors. Mutations in the gene of this receptors can cause cancer.

ENO1 is a homodimeric soluble protein that encodes a smaller monomeric structural lens protein, tau-crystallin. ENO1 is a glycolytic enzyme expressed in mainly all tissues. ENO1 isoenzyme full length protein is found in the cytoplasm. The shorter protein is formed from another translation start that is restricted to the nucleus, and binds to a component in the c-myc promoter. ENO1 is involved in anaerobic metabolism under hypoxic conditions and plays a role as a cell surface plasminogen receptor during tissue invasion. Irregular expression of Enolase-1 is linked with tumor progression in several cases of breast and lung cancer. Enolase-1 is as an auto antigen associated with Hashimoto's encephalopathy and severe asthma. ENO1 is the target protein of serum anti-endothelial antibody in Behcet's disease.

PDCD12 (AVEN) represents a new class of cell death regulator. PDCD12 is a conserved intracellular membrane protein which blocks apoptosis impeded by Apaf-1 mediated caspase activation. BAD and Bcl-2 also interact with PDCD12 to prevent apoptosis. PDCD12 is expressed in a wide variety of normal tissues including the heart, skeletal muscle, kidney, liver, testis, and also in diseases such as cancer.

The scaffolding protein encoded by the CAV1 gene is the key component of the caveolae plasma membranes found in most cell types. Cholesterol is vital for caveolae formation and maintenance, and caveolae structure is highly sensitive to cholesterol depletion or treatment with cholesterol binding drugs. CAV1 can tightly and specifically bind free cholesterol and artificial cholesterol containing vesicles. Caveolin 1 links integrin subunits to the tyrosine kinase FYN, which is an initiating step in coupling integrins to the Ras-ERK pathway and promoting cell cycle progression. CAV1 is a tumor suppressor gene candidate and a negative regulator of the Ras-p42/44 mitogen-activated kinase. Caveolin 1 and caveolin 2 are positioned next to each other on chromosome 7 and express co-localizing proteins which form a stable hetero-oligomeric complex cascade. Mutations in the CAV1 gene are linked to Berardinelli-Seip congenital lipodystrophy.

PPARGC1A is transcriptional coactivator for steroid receptors and nuclear receptors which increases the transcriptional activity of PPARG and thyroid hormone receptor on the uncoupling protein promoter. PPARGC1A regulates main mitochondrial genes that contribute to the program of adaptive thermogenesis and plays an important role in metabolic reprogramming in response to dietary availability through coordination of the expression of many genes participate in glucose and fatty acid metabolism. PPARGC1A induces the expression of PERM1 in the skeletal muscle and takes part in the integration of the circadian rhythms and energy metabolism.

CISD1 protein holds a CDGSH iron-sulfur domain and is known to bind a redox-active [2Fe-2S] cluster. CISD1 is restricted to the outer membrane of mitochondria and takes part in oxidation regulation.

LYVE-1 has been identified as a major receptor for HA (extracellular matrix glycosaminoglycan hyaluronan) on the lymph vessel wall. The deduced amino acid sequence of LYVE-1 predicts a 322-residue type I integral membrane polypeptide 41% similar to the CD44 HA receptor with a 212-residue extracellular domain containing a single Link module the prototypic HA binding domain of the Link protein superfamily. Like CD44, the LYVE-1 molecule binds both soluble and immobilized HA. However, unlike CD44, the LYVE-1 molecule colocalizes with HA on the luminal face of the lymph vessel wall and is completely absent from blood vessels. Hence, LYVE-1 is the first lymph-specific HA receptor to be characterized and is a uniquely powerful marker for lymph vessels themselves.

CRABP1 is a member of special carrier proteins for members of the vitamin A family. It is believed that CRABP1 has an essential role in retinoic acid-mediated differentiation and proliferation processes. Though, CRABP1 is structurally similar to the cellular retinol-binding proteins, it binds only retinoic acid at specific sites within the nucleus, which may contribute to vitamin A-directed differentiation in epithelial tissue. CRABP1 is constitutively expressed and is thought to have different functions in the cell than the related CRABP2. CRABP1 forms a beta-barrel structure which accommodates hydrophobic ligands in its interior. Loss of CRABP1 function as a result of hypermethylation of its promoter leads to pathogenesis of papillary thyroid carcinoma. Furthermore, frequent methylation-associated silencing of CRABP1 is linked to esophageal squamous-cell carcinoma.

Glutamyl endopeptidase (GLU-C) is an enzyme which cleaves peptide bonds on the carboxyl-terminal side of glutamic acid and, less frequently, aspartic acid (for example: Glu-|-Xaa, Asp-|-Xaa). GLU-C is a pathogenic factor involved in the adherence and colonization of human tissue. GLU-C preferentially cleaves peptide bonds on the carboxyl-terminal side of aspartate and glutamate. GLU-C is required for proteolytic maturation of thiol protease SspB and inactivation of SspC, an inhibitor of SspB. GLU-C is the most important protease for degradation of fibronectin-binding protein (FnBP) and surface protein A, which are involved in adherence to host cells. Furthermore, GLU-C protects bacteria against host defense mechanism by cleaving the immunoglobulin classes IgG, IgA and IgM. GLU-C may also be involved in the stability of secreted lipases.

Receptors across the cell membrane interact with some viral glycoproteins therefor enabling HSV to enter the host cell. The HSV enter through pores created by the binding of particular receptors across the cell membrane with the virus's coating envelope, following by a fusion of the HSV and the host cell. HSV enters the host cell through the same mechanism and stages as other viruses do. Initially, matching receptors across the virus's envelope and host cell's membrane interacts and bring the two together. During the transitional stage, begins fusion between the host cell and virus (hemifusion state). The closing stage happens when a steady pore was made; through these pores the virus's particles enter the cell.

Glutathione peroxidase 3 (GPX3) is a member of the glutathione peroxidase family, which acts in the detoxification of hydrogen peroxide. GPX3 shields cells and enzymes from oxidative damage, by catalyzing the reduction of hydrogen peroxide, lipid peroxides and organic hydroperoxide, by glutathione. The GPX3 protein is one of only a few proteins known in higher vertebrates to contain selenocysteine, which occurs at the active site of glutathione peroxidase and is coded by the nonsense (stop) codon TGA.

AK3L1 is an affiliate of the adenylate kinase family of enzymes. AK3L1 enzyme is restricted to the mitochondrial matrix. Adenylate kinases-3 regulates the adenine and guanine nucleotide compositions within a cell by means of catalyzing the reversible transfer of phosphate group among these nucleotides. 5 different isozymes of adenylate kinase have been identified in vertebrates. The enzyme expression of various adenylate kinase isozymes is growth regulated and tissue-specific.

GLRX2 is a multifunctional enzyme with glutathione-dependent oxidoreductase, glutathione peroxidase and glutathione S-transferase (GST) activity. The disulfide bond functions as an electron carrier in the glutathione-dependent synthesis of deoxyribonucleotides by the enzyme ribonucleotide reductase. In addition, it is also involved in reducing cytosolic protein- and non-protein-disulfides in a coupled system with glutathione reductase. Required for resistance to reactive oxygen species (ROS) by directly reducing hydroperoxides and for the detoxification of ROS-mediated damage. Glutaredoxins are a family of glutathione-dependent hydrogen donors that participate in a variety of cellular redox reactions.

C1q is the first component of the classical pathway of complement activation. C1q along with the enzymatically active components C1r and C1s forms the C1 complex. When C1 binds to immunoglobulins in the form of immune complexes, it leads to activation of C1r and C1s proteases and a further activates the classical pathway of complement.
C1q is a glycoprotein that belongs to the collectin family, having a molecular weight of about 410-462 kDa. C1q is a hexamer composed of globular heads attached to collagen-like triple-helix tails. The globular heads of C1q exclusively bind to the CH2 domain of IgG molecules or the CH3 domain of IgM. Each heavy chain of the immunoglobulin molecule contains a single binding site for C1q. Given that C1q must bind to no less than two heavy chains in order to alter its conformation and activate C1r and C1s, its activation follows only after binding to immunoglobulins in the form of immune complexes bound to multivalent antigens. C1q’s main physiological role is in the clearance of immune complexes and apoptotic bodies from the organism. Interruption of this process may lead to development of autoimmunity. Individuals with genetic deficiencies of C1q or other components of the classical pathway are at risk to develop SLE. C1q specifically binds to apoptotic bodies of human keratinocytes, vascular endothelial cells and lymphocytes. Complement components C1q and bound C3 mediate the clearance of apoptotic bodies. Hence, C1q may advance the clearance of autoantigens, avoiding stimulation of the immune system. Nonetheless, an extended exposition of the immune system to the neoepitope exposed on C1q molecules bound to immune complexes or apoptotic bodies could ultimately lead to an autoimmune response against C1q itself and to an altered complement function. C1q deficiency may also lead to disruption of the negative selection of autoreactive B cells. C1q along with other specific recognition proteins bind to the highly conserved lupus antigens (dsDNA and nuclear proteins) and activate the complement system. Autoantibodies against C1q (anti-C1q) are found in a number of autoimmune and infectious diseases like glomerulonephritis (GN) and lupus erythematosus (SLE), these antibodies are significant in clinical practice due to their negative predictive value.

CKMT1A is in charge of the transfer of high energy phosphate from mitochondria to the cytosolic carrier, creatine. CKMT1A is a member of the creatine kinase isoenzyme family and exists as two isoenzymes, sarcomeric MtCK and ubiquitous MtCK, encoded by separate genes. Mitochondrial creatine kinase arises in two different oligomeric forms: dimers and octamers, unlike the exclusively dimeric cytosolic creatine kinase isoenzymes. Numerous malignant cancers with poor prognosis have displayed overexpression of ubiquitous mitochondrial creatine kinase which is linked to high energy turnover and inability to remove cancer cells through apoptosis.

AKR1C1 transfers progesterone to its inactive state or in other words catalyzes the reaction of 20-alpha-hydroxy progesterone (20-alpha-OHP). In the liver and intestine. AKR1C1 transfers bile and monitors the intrahepatic bile acid concentration though it has a low bile-binding ability. AKR1C1 participates in myelin formation. AKR1C1 is part of the aldo/keto reductase superfamily, which has over 40 known enzymes which catalyze the conversion of aldehydes and ketones to their corresponding alcohols by utilizing NADH and/or NADPH as cofactors thus display overlapping but distinct substrate specificity.

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway. HK3 encodes hexokinase 3. Similar to hexokinases 1 and 2, this allosteric enzyme is inhibited by its product glucose-6-phosphate. Hexokinase3 lacks the hydrophobic N-terminal sequence critical for targeting to mitochondria. Hexpkinase3 may have anabolic functions, providing H6P for glycogen or lipid synthesis.

GH is a member of the somatotropin/prolactin family of hormones which play an important role in growth control. The gene, along with four other related genes, is located at the growth hormone locus on chromosome 17 where they are interspersed in the same transcriptional orientation; an arrangement which is thought to have evolved by a series of gene duplications. The five genes share a remarkably high degree of sequence identity. Alternative splicing generates additional isoforms of each of the five growth hormones, leading to further diversity and potential for specialization. This particular family member is expressed in the pituitary but not in placental tissue as is the case for the other four genes in the growth hormone locus. Mutations in or deletions of the gene lead to growth hormone deficiency and short stature.

Cystatins are a superfamily of cysteine proteinase inhibitors found in both plants and animals. They comprise a group of proteinase inhibitors, widely distributed in tissues and body fluids, and form tight complexes with cysteine proteases such as cathepsin B, H, L and S. Cystatin C, a secreted molecule of this family, is of interest from biochemical, medicine and evolutionary points of view. Cystatin C, with molecular weight of 13260 Da, is composed of 120 amino acids, lacks carbohydrate and has two disulfide bridges located near the carboxyl terminus. Cystatin C is increased in patients with malignant diseases, and is related to the insufficiency of renal function and appears to be a better marker than creatinine. On the other hand, low levels of cystatin C involve cause the breakdown of the elastic laminae and, subsequently, the atherosclerosis and abdominal aortic aneurysm.

GMCSF is a cytokine that controls the production, differentiation, and function of granulocytes and macrophages. The active form of the protein is found extracellularly as a homodimer. This gene has been localized to a cluster of related genes at chromosome region 5q31, which is known to be associated with interstitial deletions in the 5q- syndrome and acute myelogenous leukemia. Other genes in the cluster include those encoding interleukins 4, 5, and 13.
GM-CSF stimulates the growth and differentiation of hematopoietic precursor cells from various lineages, including granulocytes, macrophages, eosinophils and erythrocytes. Granulocyte Macrophage Colony Stimulating Factor is a potent species-specific growth factor produced by a variety of cell types including T cells, B cells, macrophages, mast cells and endothelial cells. GM-CSF is produced in response to cytokine or immune stimulation and has been shown to stimulate the proliferation, maturation and function of hematopoietic cells.

Apolipoprotein-D is mainly associated with high density lipoproteins in human plasma. Apolipoprotein-D is an atypical apolipoprotein and, based on its primary structure, Apolipoprotein-D is a member of the lipocalin family. Lipocalins adopt a beta-barrel tertiary structure and transport small hydrophobic ligands. Apolipoprotein-D binds cholesterol, progesterone, pregnenolone, bilirubin and arachidonic acid.
Apolipoprotein-D is expressed in numerous tissues having high levels of expression in spleen, testes and brain. Apolipoprotein-D is present at high concentrations in the cyst fluid of women with gross cystic disease of the breast, a condition associated with increased risk of breast cancer. Apolipoprotein-D accumulates in regenerating peripheral nerves and in the cerebrospinal fluid of patients with neurodegenerative conditions, such as Alzheimer's disease. Apolipoprotein-D participates in maintenance and repair within the central and peripheral nervous systems. Apolipoprotein-D is a multi-ligand, multi-functional transporter and transports a ligand from 1 cell to another within an organ, scavenge a ligand within an organ for transport to the blood or could transport a ligand from the circulation to specific cells within a tissue.

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.

Zinc-alpha-2-glycoprotein (ZAG) is found in body fluids such as serum, sweat, and seminal and breast cyst fluids. It is identical in amino acid sequence to tumor-derived lipid mobilizing factor (LMF), a protein associated with the dramatic loss of adipose body stores in cancer cachexia, and has been shown to stimulate lipolysis by adipocytes in vivo and in vitro. A role for ZAG has been proposed in the regulation of body weight, and age-dependent changes in genetically influenced obesity, and also it regulates melanin production by normal and malignant melanocytes. It has also recently been classified as a novel adipokine in that it is produced by both white and brown fat adipocytes and may act in a local autocrine fashion in the reduction of adiposity in cachexia. Controlling ZAG/LMF's activity could be life-saving in the management of certain cancers and other cachexiainducing conditions, and its possible normal role in body fat store homeostasis is deserving of understanding in its own right. ZAG exhibits a class I major histocompatibility complex (MHC) fold but is a soluble protein rather than being anchored to plasma membranes and does not associate with alpha-2-microglobulin in humans. Like antigen-presenting MHC class I proteins, ZAG has an open apical groove, and X-ray crystallography of human derived ZAG revealed an unidentifiable electron density in a similar position to that occupied by antigenic peptides in classical MHC proteins and glycolipids in isoforms of CD1. This presumptive ligand is not a peptide, and the groove is too small to hold a glycolipid such as is presented by CD1 isoforms. By analogy with all other MHC class I-related proteins that have an open apical groove [some do not ], occupancy by a ligand is probably crucial to ZAG's biological function. Despite all of the structural and biochemical evidence that ZAG binds a ligand, none has so far been found by extraction from protein isolated from biological fluids. This difficulty could be because the ligand is labile, heterogeneous, or readily lost during purification procedures. Knowing more about how ZAG interacts with the compounds it has been found to bind, both natural and artificial, will inform searches for the elusive ligand(s) and its/their role in ZAG's signaling function.

ST6GAL1 also known as ST6 Beta-Galactosamide Alpha-2,6-Sialyltranferase 1, is part of the glycosyltransferase family 29. ST6GAL1 is a type II membrane protein which catalyzes the transfer of sialic acid from CMP-sialic acid to galactose-containing substrates. Furthermore, ST6GAL1 is normally found in the Golgi however it can be proteolytically processed to a soluble form, ST6GAL1 is also involved in the generation of the cell-surface carbohydrate determinants as well differentiation antigens HB-6, CD75, and CD76.