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The signal sequence receptor (SSR) is a glycosylated endoplasmic reticulum membrane receptor related with protein translocation across the ER membrane. The SSR consists of 2 subunits, a 34-kD glycoprotein (alpha-SSR or SSR1) and a 22-kD glycoprotein (beta-SSR or SSR2). The human beta-signal sequence receptor gene (SSR2) maps to chromosome bands 1q21-q23. Diseases correlated with SSR2 include calcaneonavicular coalition, and osteosarcoma, and among its related super-pathways are Viral mRNA Translation and Generic Transcription Pathway.

The glucagon-like peptide-1 receptor, also known as GLP1R, is a receptor protein found on brain neurons and beta cells of the pancreas. GLP1R activates a signalling cascade that leads to the initiation of adenylyl cyclase and increased intracellular cAMP levels. In humans, GLP1R is synthesized by GLP1R gene, which is present on chromosome 6.
GLP1R takes part in the control of blood sugar level by enhancing insulin secretion. GLP1R is a part of the glucagon receptor family of G protein-coupled receptors. GLP1R consists of two domains, one transmembrane (TMD) domain, that binds the N-terminal region of GLP-1. And one extracellular (ECD) which binds the C-terminal helix of GLP-1. The TMD domain contains a fulcrum of polar residues that controls the biased signaling of the receptor, while the transmembrane helical boundaries and extracellular surface are a trigger for biased agonism.

The signal sequence receptor (SSR) is a glycosylated endoplasmic reticulum membrane receptor related with protein translocation across the ER membrane. The SSR consists of 2 subunits, a 34-kD glycoprotein (alpha-SSR or SSR1) and a 22-kD glycoprotein (beta-SSR or SSR2). The human beta-signal sequence receptor gene (SSR2) maps to chromosome bands 1q21-q23. Diseases correlated with SSR2 include calcaneonavicular coalition, and osteosarcoma, and among its related super-pathways are Viral mRNA Translation and Generic Transcription Pathway.

Eukaryotic translation initiation factor 3, subunit I (EIF3I) is part of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is essential for numerous steps in the initiation of protein synthesis. The eIF-3 complex links with the 40S ribosome and facilitates the recruitment of eIF-1, eIF-1A, eIF-2: GTP: methionyl-tRNAi and eIF-5 to form the 43S pre-initiation complex (43S PIC). The eIF-3 complex stimulates mRNA recruitment to the 43S PIC and scanning of the mRNA for AUG recognition. The eIF-3 complex is also essential for disassembly and recycling of post-termination ribosomal complexes and subsequently prevents premature joining of the 40S and 60S ribosomal subunits prior to initiation. Among the diseases associated with EIF3I are clonorchiasis, and tonsillitis.

EPHA2 is a member of the ephrin receptor subfamily of the protein-tyrosine kinase family. EPH and EPH-related receptors are implicated in mediating developmental events, particularly in the nervous system. Receptors in the EPH subfamily typically 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. The EPHA2 gene encodes a protein that binds ephrin-A ligands. Mutations in the EPHA2 gene are the origin of certain genetically-related cataract disorders.

Eukaryotic translation initiation factor 3, subunit I (EIF3I) is part of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is essential for numerous steps in the initiation of protein synthesis. The eIF-3 complex links with the 40S ribosome and facilitates the recruitment of eIF-1, eIF-1A, eIF-2: GTP: methionyl-tRNAi and eIF-5 to form the 43S pre-initiation complex (43S PIC). The eIF-3 complex stimulates mRNA recruitment to the 43S PIC and scanning of the mRNA for AUG recognition. The eIF-3 complex is also essential for disassembly and recycling of post-termination ribosomal complexes and subsequently prevents premature joining of the 40S and 60S ribosomal subunits prior to initiation. Among the diseases associated with EIF3I are clonorchiasis, and tonsillitis.

PDGFRa is a cell surface tyrosine kinase receptor for PDGF family members. PDGFRa binds to both A and B subunits of PDGF. It is known that PDGFRa is vital for kidney development since mice heterozygous for the receptor display defective kidney phenotypes.

Fibroblast Growth Factors (FGFs) comprise a family of at least eighteen structurally realted proteins that are involved in a multitude of physiological and pathological cellular processes, including cell growth, differentation, angiogenesis, wound healing and tumorgenesis. The biological activities of the FGFs are mediated by a family if type I transmembrane tyrosine kinases which undergo dimerization and autophosphorylation after ligand binding. Four distinct genes encoding closely related FGF receptors, FGFR-1to -4 are known. Multiple forms of FGFR-1 to -3 are generated by alternative splicing of the mRNAs. A frequent splicing event involving FGFR-1 and -2 results in receptors containing all three Ig domains, referred to as the alpha isoform, or only IgII and IgIII, referred to as the ? isoform. Only the alpha isoform has been identified for FGFR-3 and FGFR-4. Additional splicing events for FGFR-1 to -3, involving the C-terminal half of the IgIII domain encoded by two mutually exclusive alternative exons, generate FGF receptors with alternative IgIII domains (IIIb and IIIc). A IIIa isoform which is a secreted FGF binding protein containing only the N-terminal half of the IgIII domain plus some intron sequences has also been reported for FGFR-1. Mutations in FGFR-1 to -3 have been found in patients with birth defects involving craniosynostosis.

Fibroblast Growth Factors (FGFs) comprise a family of at least eighteen structurally realted proteins that are involved in a multitude of physiological and pathological cellular processes, including cell growth, differentation, angiogenesis, wound healing and tumorgenesis. The biological activities of the FGFs are mediated by a family if type I transmembrane tyrosine kinases which undergo dimerization and autophosphorylation after ligand binding. Four distinct genes encoding closely related FGF receptors, FGFR-1to -4 are known. Multiple forms of FGFR-1 to -3 are generated by alternative splicing of the mRNAs. A frequent splicing event involving FGFR-1 and -2 results in receptors containing all three Ig domains, referred to as the alpha isoform, or only IgII and IgIII, referred to as the ? isoform. Only the alpha isoform has been identified for FGFR-3 and FGFR-4. Additional splicing events for FGFR-1 to -3, involving the C-terminal half of the IgIII domain encoded by two mutually exclusive alternative exons, generate FGF receptors with alternative IgIII domains (IIIb and IIIc). A IIIa isoform which is a secreted FGF binding protein containing only the N-terminal half of the IgIII domain plus some intron sequences has also been reported for FGFR-1. Mutations in FGFR-1 to -3 have been found in patients with birth defects involving craniosynostosis.

Fibroblast Growth Factors (FGFs) comprise a family of at least eighteen structurally realted proteins that are involved in a multitude of physiological and pathological cellular processes, including cell growth, differentation, angiogenesis, wound healing and tumorgenesis. The biological activities of the FGFs are mediated by a family if type I transmembrane tyrosine kinases which undergo dimerization and autophosphorylation after ligand binding. Four distinct genes encoding closely related FGF receptors, FGFR-1to -4 are known. Multiple forms of FGFR-1 to -3 are generated by alternative splicing of the mRNAs. A frequent splicing event involving FGFR-1 and -2 results in receptors containing all three Ig domains, referred to as the alpha isoform, or only IgII and IgIII, referred to as the ? isoform. Only the alpha isoform has been identified for FGFR-3 and FGFR-4. Additional splicing events for FGFR-1 to -3, involving the C-terminal half of the IgIII domain encoded by two mutually exclusive alternative exons, generate FGF receptors with alternative IgIII domains (IIIb and IIIc). A IIIa isoform which is a secreted FGF binding protein containing only the N-terminal half of the IgIII domain plus some intron sequences has also been reported for FGFR-1. Mutations in FGFR-1 to -3 have been found in patients with birth defects involving craniosynostosis.

MCSFR which is also familiar as CSF1R, is part of the type3 subfamily of receptor tyrosine kinases. MCSFR is expressed mainly on cells of the monocyte and macrophage lineage, stem cells, and in the growing placenta. Most of the biological effects of this cytokine are mediated by MCSFR. MCSFR contains an extracellular ligand-binding domain, a single membrane-spanning segment, and an intracellular tyrosine kinase domain. Originally CSF1 and this receptor were implicated as vital for normal trophoblastic implantation as well as monocyte development. The role of CSF1/CSF1R in normal mammary gland development is actually very interesting since this connection has also been discovered in the biology of breast cancer with the results of abnormal expression of CSF1 and its receptor. Likewise, in Alzheimer's disease and after brain injuries an increased level of CSF1R was found in the microglia, which causes the microglia to become more active.

Estrogen receptors α (ERα, ER; NR3A1) is a member of the steroid hormone receptor family. ERα is a ligand-activated transcription factor. ERα contain DNA binding and ligand binding domains. ERα is expressed in a wide variety of tissues, including ovary, uterus, breast, prostate, testis, epididymis, bones, bladder, kidney, heart, vessel wall, pituitary gland and hypothalamus. ER plays a variety of important roles in the maintenance of the reproductive, cardiovascular, musculoskeletal and central nervous systems. The natural ligand for ER is 17β-estradiol, the classical estrogenic compound. The binding of estrogen to ER induces a conformational change and triggers a cascade of events, including dissociation from heat shock proteins, receptor dimerization, phosphorylation and the association of the hormone activated receptor with specific regulatory elements in target genes.

TNFR2 belongs to the TNF-receptor superfamily. TNFR2 is receptor with high affinity for TNFSF2/TNF-alpha and approximately 5-fold lower affinity for homotrimeric TNFSF1/lymphotoxin-alpha. TNFR2 mediates the majority of the metabolic effects of TNF-alpha. In addition, knockout studies in mice propose a role for TNFR2 in protecting neurons from apoptosis by stimulating antioxidative pathways. TNFR2 expression might have a significant role in the angiogenesis, tumor cell proliferation and metastasis of Invasive micropapillary carcinoma of the breast.
There are 2 types of soluble TNF receptors: sTNFR-I and sTNFR-II, which act to neutralize the biological activities of TNF alpha and TNF beta. The levels of these soluble receptors seem to increase as a result of shedding of the extracellular domains of the membrane bound receptors. High levels of soluble TNF receptors are found in the amniotic fluid of pregnant women. TNFR2 and TNFR1 form a heterocomplex which mediates the recruitment of 2 anti-apoptotic proteins, c-IAP1 and c-IAP2, which possess E3 ubiquitin ligase activity. IAPs’ function in TNF-receptor signaling is unknown; nevertheless, c-IAP1 is believed to potentiate TNF-induced apoptosis by the ubiquitination and degradation of TNF-receptor-associated factor 2, which mediates anti-apoptotic signals. Oxidative stress promotes TNFR1 and TNFR2 self-interaction, ligand-independent and enhanced ligand-dependent TNF signaling. TNF-a, TNFR1 and TNFR2 have roles in cellular differentiation. TNFR1 and TNFR2 function in cell type-specific renal injury.

TNFR1 belongs to the TNF-receptor superfamily. TNFR1 is a receptor for TNFSF2/TNF-alpha and homotrimeric TNFSF1/lymphotoxin-alpha.
There are 2 types of soluble TNF receptors: sTNFR-I and sTNFR-II, which act to neutralize the biological activities of TNF alpha and TNF beta. The levels of these soluble receptors seem to increase as a result of shedding of the extracellular domains of the membrane bound receptors. TNF-a, TNFR1 and TNFR2 have roles in cellular differentiation. TNFR1 and TNFR2 function in cell type-specific renal injury.
TNFR1 is capable of signaling both cell survival and apoptosis. TNFR1-induced apoptosis requires 2 sequential signaling complexes. TNFR1 is capable of activating NF-kappaB, mediate apoptosis, and function as a regulator of inflammation. Oxidative stress promotes TNFR1 and TNFR2 self-interaction, ligand-independent and enhanced ligand-dependent TNF signaling. TNFR1 contributes to the induction of non-cytocidal TNF effects including anti-viral state and activation of the acid sphingomyelinase. Human TNFR1 has a major region which controls cell surface expression. High levels of soluble TNF receptors are found in the amniotic fluid of pregnant women.
Germline mutations of the extracellular domains of TNFR1 are linked to the autosomal dominant periodic fever syndrome. The impaired receptor clearance is believed to be a mechanism of the disease. Familial hibernian fever (FHF) is caused by defects in TNFRSF1A gene.

TGFBR2 is part of the Ser/Thr protein kinase family and the TGFB receptor subfamily. TGFBR2 is a transmembrane protein that has a protein kinase domain, forms a heterodimeric complex with another receptor protein, and binds TGF-beta. This receptor/ligand complex phosphorylates proteins, which then enter the nucleus and regulate the transcription of a subset of genes related to cell proliferation. Mutations in TGFBR2 gene have been associated with Marfan syndrome, Loeys-Deitz Aortic Aneurysm Syndrome, and the development of various types of tumors. TGFBR2 expression is increased in oral squamous cell carcinoma cells. TGFBR2 attenuates the biological activities of TGF-beta in colorectal cancer. TGFBR2 expression is decreased by IL-1beta while inducing Sp3 via NFkappaB. TGFB2 and TGFBR2 are involved in the antiestrogenic activity of tamoxifen metabolites in breast cancer.

Transferrin receptor protein 1 (TFRC) is required for iron delivery from transferring to cells. The TFRC protein is a transmembrane glycoprotein comprised of 2 disulfide-linked monomers joined by 2 disulfide bonds. Each monomer will bind one holo-transferrin molecule producing an iron-Tf-TfR complex which enters the cell by endocytosis.

EEF1A1 is an isoform of the alpha subunit of the elongation factor-1 complex, which is responsible forthe enzymatic release of aminoacyl tRNAs to the ribosome. EEF1A1 is expressed in brain, placenta, lung, liver, kidney, and pancreas, and the other isoform (alpha 2) is expressed in brain, heart and skeletal muscle. EEF1A1 is recognized as an autoantigen in 66% of patients with Felty syndrome. EEF1A1 has multiple copies on numerous chromosomes, part of them, if not all, symbolize different pseudogenes. Among the diseases associated with EEF1A1 are tinea nigra and andcervical cancer.

Endothelial cells express three different vascular endothelial growth factor (VEGF) receptors, belonging to the family of receptor tyrosine kinases (RTKs). They are named VEGFR-1 (Flt-1), VEGFR-2 (KDR/Flk-1), VEGFR-3 (Flt-4). Their expression is almost exclusively restricted to endothelial cells, but VEGFR-1 can also be found on monocytes, dendritic cells and on trophoblast cells. The flt-1 gene was first described in 1990. The receptor contains seven immunoglobulin-like extracellular domains, a single transmembrane region and an intracellular splited tyrosine kinase domain. Compared to VEGFR-2 the Flt-1 receptor has a higher affinity for VEGF but a weaker signaling activity. VEGFR-1 thus leads not to proliferation of endothelial cells, but mediates signals for differentiation. Interestingly a naturally occuring soluble variant of VEGFR-1 (sVEGFR-1) was found in HUVE supernatants in 1996, which is generated by alternative splicing of the flt-1 mRNA. The biological functions of sVEGFR-1 still are not clear, but it seems to be an endogenous regulator of angiogenesis, binding VEGF with the same affinity as the full-length receptor.

EPH Receptor B1 (EPHB1) is a member of the ephrin receptor subfamily of the proteintyrosine kinase family which 16 receptors are known. EPHB1 binds ephrin-B2, ephrin-B1,ephrin‑A3,ephrin-A1,ephrin-B3 and ephrin-A4. EPHB1 binds tyrosine kinase and phosphorylates syndecan-2 and thisphosphorylation is necessary for syndecan-2 clustering and spine formation. Ephrin receptors and theirligands (the ephrins) mediate several developmental processes, mainly in the nervous system.

Erythropoietin receptor, also known as EPOR arbitrates erythropoietin-induced erythroblast proliferation as well as differentiation. During EPO binding, EPOR activates Jak2 tyrosine kinase which activates various intracellular pathways including: Ras/MAP kinase, phosphatidylinositol 3-kinase and STAT transcription factors. Furthermore, stimulated EPOR has a function in erythroid cell survival. Mutations in EPOR may possibly produce erythroleukemia and familial erythrocytosis. In addition, dysregulation of EPOR can affect on the growth of selected tumors.

TRAF1 is an adapter protein and signal transducer that connects members of the TNFR family to different signaling pathways by association with the receptor cytoplasmic domain and kinases. TRAF1 mediates activation of NF-kappa-B and JNK and participates in apoptosis. The TRAF1/TRAF2 complex recruits the apoptotic suppressors BIRC2 and BIRC3 to TNFRSF1B/TNFR2.