You searched for: Proteins and Peptides

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Transforming growth factor-alpha (TGF-α) a member of the epidermal growth factor (EGF) family that is expressed in normal epithelial cells, monocytes, macrophages, brain cells, keratinocytes, and cancer cells. TGF-α binds EGF receptor (EGFR) and activates tyrosine kinase signaling. In epidermal and epithelial cells, this results in proliferation and differentiation. TGF-α is not structurally or genetically related to TGF-β, and the two ligands act through different signaling pathways. In vitro, TGF-α was shown to stimulate anchorage-independent growth (Singh and Coffey).

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Noggin binds to and antagonizes bone morphogenetic protein (BMP) ligands of the transforming growth factor beta (TGF-β) family. Noggin supports maintenance of undifferentiated human embryonic stem cells in vitro, and can be used to prevent spontaneous differentiation in the short term (Chaturvedi et al.). Noggin is essential for development of structures derived from ectoderm embryonic somite, skeletal patterning, and neurogenesis in vivo. It also influences chondrogenesis, osteogenesis, and joint formation (Krause et al.), and promotes dopaminergic differentiation of embryonic stem cells and subsequent survival of dopamine neurons (Chiba et al.).

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Stimulating T cells with CMV (HLA Class I Control) Peptide pool releases downstream cytokines and upregulates activation markers, enabling antigen-specific T cells to be detected or isolated for analysis. CMV Peptide pool is a lyophilised mixture of 14 peptides from the human cytomegalovirus (CMV) and consists of defined HLA class I-restricted T cell epitopes. Viral peptide pools are useful for a broad range of applications, including vaccine development, immunological research, and diagnostic assay development. For consistency and reproducibility across your applications, CMV Peptide pools from STEMCELL are formulated as lyophilised trifluoroacetate salts, with a purity ≥95%.

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Epidermal growth factor (EGF) is characterized by high affinity binding to various EGF receptors (EGFRs) and the production of mitogenic responses (Carpenter and Cohen). EGF promotes EGFR dimerization, resulting in activation of downstream pathways including PI3K, ERK1/2, JAK/STAT, β-catenin, and calcium signaling. EGF is secreted by the gut-associated salivary and Brunner’s glands, is found in a variety of body fluids, and stimulates cell proliferation and differentiation in rodent and neonatal human intestine (Wright et al.). Central nervous system stem cells also proliferate in response to the EGF stimulus (Reynolds and Weiss).

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Dickkopf-related protein 1 (DKK-1) is a member of the Dickkopf family and is a secreted protein that inhibits the canonical WNT pathway by competitive binding to low-density lipoprotein receptors (LRP)-5 and 6 with high affinity, thereby decreasing β-catenin protein stability (Niehrs). DKK-1 regulates embryonic development and contains two conserved cysteine-rich domains separated by a linker region and an N-terminal signal peptide (Krupnik et al.; Lieven et al.). A family of human DKK-related genes composed of DKK-1, DKK-2, DKK-3, and DKK-4 have been characterized together with a unique DKK-3 related protein termed Soggy (Krupnik et al.). DKK-1 has been shown to support the generation of myeloid-derived suppressor cells (MDSCs) and thus is a negative regulator of antitumor immune responses (D’Amico et al.). DKK-1 from thrombocytes is an important regulator of leukocyte infiltration and induces Th2 cell polarization and potentiates Th2 cell cytokine expression (Chae et al.). DKK-1 has also been shown to drive cardiac and retinal differentiation from induced pluripotent stem (iPS) cells (Lian et al.). Protein contains a His-residue tag at the carboxyl end of the polypeptide chain.

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Vascular endothelial growth factor (VEGF-121) is a naturally-occurring VEGF-A splice variant involved in embryonic vasculogenesis and angiogenesis. VEGF binds to VEGFR-1 and VEGFR-2, and activates Raf/MEK/ERK and PI3K/AKT pathways. VEGF-121 is released as a freely diffusible protein by a variety of normal and transformed cells. It plays an important role in neurogenesis both in vitro and in vivo (Storkebaum et al.). It has neurotrophic effects on neurons of the central nervous system and promotes growth and survival of dopaminergic neurons and astrocytes. VEGF also promotes growth and survival of vascular endothelial cells, monocyte chemotaxis, and colony formation by granulocyte-macrophage progenitor cells (Ferrara et al.).

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Stimulating T cells with VZV (IE63) peptide pool releases downstream cytokines and upregulates activation markers, enabling antigen-specific T cells to be detected or isolated for analysis. VZV (IE63) peptide pool is a lyophilised mixture of 67 peptides from the transcriptional regulator ICP22 homolog (IE63) of Varicella-zoster virus (VZV; strain Oka vaccine), and consists of 15-mer peptides with 11-amino-acid overlaps that cover amino acids 1 to 278 on IE63. Expressed during VZV latency and reactivation (Lungu et al.), IE63 demonstrates repressive activity in both the cytoplasm and nucleus of infected cells (Bontems et al.). Host interferon alpha (IFN-α) activity is inhibited by VZV IE63, which likely contributes to VZV pathogenesis (Ambagala and Cohen). Viral peptide pools are useful for a broad range of applications, including vaccine development, immunological research, and diagnostic assay development.

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Stimulating T cells with EBV (EBNA-3A) Peptide pool releases downstream cytokines and upregulates activation markers, enabling antigen-specific T cells to be detected or isolated for analysis. EBV (EBNA-3A) Peptide pool is a lyophilised mixture of 234 peptides from Epstein-Barr nuclear antigen 3 (EBNA-3A) of Epstein-Barr virus (EBV; strain B95-8) and consists of 15-mer peptides with 11-amino-acid overlaps that cover amino acids 1 to 944 on EBNA-3A. EBNA-3A contributes to B cell growth transformation (Hertle et al.; Tomkinson et al.) and has been found to interact with host cell proteins, where it activates (Young et al.) or represses (Cludts and Farrell; Hickabottom et al.) transcription of specific cellular genes. Viral peptide pools are useful for a broad range of applications, including vaccine development, immunological research, and diagnostic assay development.

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Stimulating T cells with CMV (UL44) peptide pool releases downstream cytokines and upregulates activation markers, enabling antigen-specific T cells to be detected or isolated for analysis. CMV (UL44) peptide pool is a lyophilised mixture of 106 peptides from DNA polymerase processivity factor UL44 of human cytomegalovirus (CMV; strain AD169), and consists of 15-mer peptides with 11-amino-acid overlaps that cover amino acids 1 to 433 on UL44. UL44 contains a nuclear localization signal (Alvisi et al.) and may bind DNA directly, or form a C clamp partially surrounding it, similar to proliferation cell nuclear antigen (PCNA) (Appleton et al.). UL44 has also been found to interact with viral (Kim and Ahn) and host (Strang et al.) proteins that contribute to viral DNA replication and efficient viral growth. Viral peptide pools are useful for a broad range of applications, including vaccine development, immunological research, and diagnostic assay development.

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SARS-CoV-2 Recombinant Nucleocapsid Protein, aa1-419 is expressed in HEK293 cells and is one of four structural proteins encoded by the SARS-CoV-2 genome. The Nucleocapsid Protein is transcribed from the viral “N” gene and is the protein that interacts with RNA to form the nucleocapsid. The protein forms a homo-oligomer, and both the monomer and the oligomer can interact with RNA. This protein also interacts with the membrane protein (protein M) after infection of the host cell during packaging of the positive-strand viral genome RNA into the ribonucleocapsid during virion assembly.

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Follistatin, a glycosylated monomeric protein, is a modulator of transforming growth factor beta (TGF-β) superfamily signaling. It binds to and inhibits the function of activin, myostatin, growth differentiation factors, and bone morphogenetic proteins (BMP) (Hansen and Plomgaard). Follistatin inhibits mesoderm induction, suppresses synthesis and secretion of pituitary follicle-stimulating hormone, regulates liver regeneration, and causes infertility (Guo et al.; Iemura et al.). Follistatin exhibits anti-inflammatory effects, and it could be used as a biomarker in cancer (Hansen and Plomgaard).

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Amphiregulin is a member of the epidermal growth factor (EGF) family. It binds to several receptors including EGFR/ErbB1, HER2/ErbB2, HER3/ErbB3, and HER4/ErbB4, which activates Ras/Raf/MAPK and PI3K/AKT pathways. This results in cell proliferation, apoptosis resistance, and invasive behaviour (Normanno et al.). The expression of amphiregulin is induced by tissue injury and inflammation. Amphiregulin promotes mammary development, trophoblast growth, lung and kidney branching morphogenesis, and keratinocyte proliferation. It stimulates the growth of most cell types, including normal and transformed mammary epithelial cells, and malignant cells of the colon, prostate, cervix, and pancreas (Berasain and Avila).

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Prolactin is a peptide hormone of pituitary origin and is well known for the stimulation, initiation, and maintenance of lactation. Prolactin is also known to regulate mammary gland development and immune system, and has an essential role in metabolism and behavioral modification (Bernichtein et al.). Prolactin actions are mediated by the prolactin receptor (PRLR), which is a single-chain transmembrane protein composed of an extracellular, transmembrane, and intracellular domain. It has also been indicated that high to normal circulating levels of prolactin increase breast cancer risk, and dopamine agonists have been suggested to be effective for treatment (Bernichtein et al.). Prolactin levels have been reported to be higher in multiple sclerosis patients, which promotes B cell autoreactivity (Correale et al.). It has been shown that administration of recombinant prolactin after bone marrow transplantation in mice promotes immune and myeloid reconstitution (Sun et al.).

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Insulin-like growth factor 1 (IGF-I) is a polypeptide that belongs to the family of insulin-like growth factors that are similar in molecular structure to proinsulin. IGF-I binds to the IGF-I receptor and is a potent activator of the PI3K/AKT pathway and also activates ERK1/2 signaling. IGF-I is required for embryonic development, and it is produced mainly in the liver in response to a hepatocyte growth hormone. In the absence of insulin, IGF-I is necessary for the maintenance of human pluripotent stem cells (Wang et al.). Together with IL-3, IGF-I stimulates differentiation and proliferation of myeloid cells and has been shown to regulate lymphopoiesis by stimulating proliferation and differentiation of T and B cells in lymphoid organs (Heemskerk et al.).

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Neurotrophin-4 (NT-4) is a member of the nerve growth factor family which includes neurotrophin-3 (NT-3), brain-derived neurotrophic factor (BDNF), and nerve growth factor (NGF), all of which promote the differentiation, growth, and survival of peripheral and central nervous system neurons (Eide et al.). NT-4 binds and activates tropomyosin receptor kinase B (TrkB) at the cell surface; in doing so, it acts as a survival factor for certain populations of sensory neurons (Berkemeier et al.; Skaper). It has been shown that NT-4, together with BDNF, promotes neurite extension and maturation, as well as maintenance of differentiated cerebellar granule cells (Gao et al.).

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Chemokine ligand 19 (CCL19), also known as macrophage inflammatory protein-3 beta (MIP-3β), is a member of the CC chemokine family, which plays key roles in inflammatory responses, T cell activation, homeostasis, and development (Yan et al.). CCL19 is expressed in lymph nodes, thymus, and activated bone marrow stromal cells; it binds to C-C motif chemokine receptor 7 (CCR7) to induce migration of macrophages, T cells, and B cells (Gibejova et al.). Clinically, the expression of CCL19 is correlated to autoimmune diseases such as rheumatoid arthritis and cancer (Pickens et al.; Zhang et al.).

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Growth differentiation factor 5 (GDF-5) is a member of the bone morphogenetic protein (BMP) subclass of the transforming growth factor beta (TGF-β) superfamily. It binds a receptor complex comprising BMPR1B and BMPR2, which then activates the SMAD signaling pathway (Carreira et al.; Nishitoh et al.; Osório et al.). GDF-5 enhances chondrogenic differentiation of mesenchymal stem cells, skeletogenesis, and dendrite growth during development (Coleman et al.; Francis-West et al.). Studies in rat demonstrated that GDF-5 regulates patterning, neurogenesis, astrogliogenesis, and neuronal specification (Gajavelli et al.; Krieglstein et al.; O’Keeffe et al.).

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Transforming growth factor (TGF) beta 2 is a member of the TGF-β superfamily and regulates diverse cellular phenotypes. Similar to TGF-β1 and -β3, TGF-β2 signals via serine-threonine kinase type I and II receptors and activates signal transduction via SMAD family proteins, regulating a variety of functions such as cell proliferation, differentiation, wound healing, apoptosis, and metabolism (de Caestecker; Massague; Zuniga et al.). TGF-β2 is important in many developmental processes; for example, mice with TGF-β2 deletions show defects in the development of cardiac, lung, craniofacial, limb, eye, ear, and urogenital systems (Dunker and Kreiglstein).

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SARS-CoV-2 Recombinant Spike Protein, aa16-685 is expressed in HEK293 cells and is one of four structural proteins encoded by the SARS-CoV-2 genome. The Spike Protein plays a key role in attachment to host cells, allowing invasion through clathrin-mediated endocytosis. The Spike Protein can be cleaved by host cell proteases after aa685 to yield the N-terminal S1 subunit and C-terminal S2 region. The S1 subunit is responsible for interacting with the host cell receptor (angiotensin-converting enzyme II) through a receptor-binding domain that is highly conserved with SARS-CoV. The S1 subunit has two conformations: a ‘down’ conformation in which the receptor is inaccessible, and an ‘up’ conformation in which the receptor is accessible. These conformational changes are key for monoclonal antibody drugs and vaccine development. SARS-CoV-2 Recombinant Spike Protein contains a polyhistidine tag at the amino terminus; it also contains a FLAG tag at the carboxy terminus.

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R-Spondin-3 is a member of thrombospondin type 1 repeat (TSR-1) superfamily that is involved in the canonical Wnt/β-catenin signaling pathway (de Lau et al.). R-spondin proteins are characterized by two furin-like repeats at the amino terminus and thrombospondin domain located near the carboxyl terminus (de Lau et al.). R-spondin-3 expression is associated with ovarian cancer (Gu et al.), prostate cancer (Mesci et al.), and differentiation of intestinal epithelial cells in diabetes mellitus (Shan et al.). In a transgenic mice model, the expression of R-Spondin-3 induces the expansion of Lgr5+ stem cells, Paneth cells, and Lgr4+ cells, promoting the intestinal stem cell compartment (Hilkens et al.). This protein contains a His-residue tag at the carboxyl end of the polypeptide chain.

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Bone morphogenetic protein 2 (BMP-2) is a member of the transforming growth factor beta (TGF-β) superfamily. BMP-2 is a disulfide-linked homodimer, acts as a ligand for complexes of type I and II BMP receptors, and primarily activates SMAD1/5/8 signaling (Nohe et al.). BMP-2 is a potent differentiation factor and directs human pluripotent stem cells (hPSCs) towards various cell types including extra-embryonic endoderm, mesenchymal cells, and chondrocytes (Pera et al.). Although BMP-2 expression is low in healthy cartilage, its expression is upregulated at the site of cartilage damage (Blaney Davidson et al.). BMP-2 induces bone and cartilage formation in vitro and is able to induce chondrogenesis in human mesenchymal stem cells (Schmitt et al.).

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SARS-CoV-2 Recombinant Spike Protein, aa319-541 is expressed in Pichia pastoris and is one of four structural proteins encoded by the SARS-CoV-2 genome. The Spike Protein plays a key role in attachment to host cells allowing invasion through clathrin-mediated endocytosis. The spike protein can be cleaved by host cell proteases after aa685 to yield the N-terminal S1 subunit, and C-terminal S2 region. The S1 subunit is responsible for interacting with the host cell receptor (angiotensin-converting enzyme II) through a receptor-binding domain that is highly conserved with SARS-CoV. The S1 subunit has two conformations: a ‘down’ conformation in which the receptor is inaccessible, and an ‘up’ conformation in which the receptor is accessible. These conformational changes are key for monoclonal antibody drugs and vaccine development. At the amino terminus of the polypeptide chain, SARS-CoV-2 Recombinant spike protein contains a polyhistidine tag and a SUMOstar site.

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Fibroblast growth factor 8A (FGF-8A) is a member of the fibroblast growth factor (FGF) family and is an isoform of FGF-8. FGF-8A binds the FGF receptor (FGFR) and activates Ras/MAPK signaling (Hulstrand and Houston). The FGF family possesses broad mitogenic and cell survival activities (Folkman and Klagsbrun; Kimelman and Kirschner) and is involved in a variety of biological processes, including cell proliferation, differentiation, survival, and apoptosis (Folkman and Klagsbrun; Klagsbrun; Rifkin and Moscatelli). FGF-8 RNA is spliced to produce 4 protein isoforms in humans: FGF-8A, FGF-8B, FGF-8E, and FGF-8F. The functional differences are not fully understood; however, studies in zebrafish and Xenopus show that FGF-8A is required for endoderm morphogenesis and neurogenesis (Choe and Crump; Hulstrand and Houston).

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Stimulating T cells with EBV (GP350/340) Peptide pool releases downstream cytokines and upregulates activation markers, enabling antigen-specific T cells to be detected or isolated for analysis. EBV (GP350/340) Peptide pool is a lyophilised mixture of 224 peptides from envelope glycoprotein GP350 (GP350/340) of Epstein-Barr virus (EBV; strain B95-8), and consists of 15-mer peptides with 11-amino-acid overlaps that cover amino acids 1 to 907 on GP350/340. GP350 meditates EBV attachment to B lymphocytes via binding to the cell surface receptor CR2 (also known as C3d receptor or CD21) (Nemerow et al.; Tanner et al.). Viral peptide pools are useful for a broad range of applications, including vaccine development, immunological research, and diagnostic assay development.

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TRAIL (TNF-related apoptosis-inducing ligand) belongs to the tumor necrosis factor (TNF) superfamily and is associated with initiating apoptosis. TRAIL has four major receptors: two death receptors DR4 and DR5, and two decoy receptors DcR1 and DcR2. TRAIL binds to the death receptors, which recruits the Fas-associated death domain (FADD) and activates caspases 8 and 10, which eventually leads to apoptosis (Pitti et al.; Wiley et al.; Zauli and Secchiero). It has been shown that mice lacking the expression of TRAIL have defects in thymocyte apoptosis and negative selection, and these mice had increased susceptibility to autoimmune diseases (Lamhamedi-Cherradi et al.).

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Activin A is a member of the transforming growth factor beta (TGF-β) family of proteins produced by many cell types throughout development (Gurdon et al.). It is a disulfide-linked homodimer (two beta-A chains) that binds to heteromeric complexes of a type I (Act RI-A and Act RI-B) and a type II (Act RII-A and Act RII-B) serine-threonine kinase receptor (Attisano et al.). Activins primarily signal through SMAD2/3 proteins to regulate a variety of functions, including cell proliferation, differentiation, wound healing, apoptosis, and metabolism (McDowell et al.). Activin A maintains the undifferentiated state of human embryonic stem cells (James et al.; Xiao et al.) and also facilitates differentiation of human embryonic stem cells into definitive endoderm (D’Amour et al.). This product is animal component-free.

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Receptor activator of nuclear factor kappa-B ligand (RANKL) is a member of the tumor necrosis factor (TNF) superfamily (Anderson et al.). Cytokines in the TNF superfamily are involved in a variety of long-term cellular activities such as differentiation, proliferation, and cell death (MacEwan). RANKL is a type II homotrimeric transmembrane protein expressed in both a membrane-bound and secreted form (Ikeda et al.). RANKL binds to the receptor activator of nuclear factor kappa-B (RANK). Upon binding to its receptor, RANKL activates the AKT signaling pathway (Moon et al.). Osteoprotegerin (OPG) may also bind RANKL, and this binding competes with RANKL-RANK binding (Lacey et al.). RANKL is involved in osteoclastogenesis (Lacey et al.; Yasuda et al.) and T cell activation (Wong et al.).

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Human Recombinant Angiotensin-Converting Enzyme 2 (ACE2) Protein, aa18-740, is expressed in HEK293 cells. ACE2 activity results in vasodilation by degrading vasoconstrictor angiotensin II to produce vasodilator angiotensin. Decreased expression of this enzyme is associated with cardiovascular disease and possibly also glomerular injury in diabetic nephropathy. ACE2 contains a peptidase domain at the N-terminus and a single transmembrane helix. ACE2 is also the primary human receptor for the surface spike glycoprotein of SARS-CoV-2 and SARS-CoV. This receptor is expressed in human lung and small intestine epithelia as well as the heart, kidney, and testes. The peptidase domain of ACE2 binds to the protein-binding domain of the S1 protein subunit of the spike protein; this binding results in a cleavage site becoming exposed. Cleavage, or ‘protein priming’, is done by TMPRSS2, a cellular serine protease, and by cathepsins. This cleavage activates the S2 subunit of the spike protein, allowing the fusion of the viral membrane to the host cell membrane. At the carboxy terminus, Human Recombinant ACE2 Protein contains a TEV site and a human IgG1 Fc tag.

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Indian hedgehog (IHH) is one of three proteins in the hedgehog family which includes sonic hedgehog and desert hedgehog. Hedgehog proteins are important signaling molecules, acting through patched and smoothened receptors. During embryonic development, they are expressed in the fetal lung, gut, stomach, liver, kidney, and pancreas. IHH is strongly expressed in cartilage and regions of developing bone, and its signaling regulates growth and differentiation of bone tissue (Marigo et al.; Valentini et al.; St-Jacques et al.). IHH is also involved in yolk sac vasculogenesis, indicating a role in the differentiation of epiblast cells into endothelial and red blood cells (Byrd et al.). IHH induces the expression of parathyroid hormone-related peptide (PTHrP), which negatively regulates IHH during chondrocyte differentiation and proliferation (Vortkamp et al.).

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Interleukin 5 (IL-5) is a member of the short-chain 4-α-helical bundle subset of hematopoietic cytokines. It binds to a receptor consisting of IL-5Ra, which is specific for IL-5R, and common beta chain, which is shared with the receptor for IL-3 and GM-CSF (Shearer). Upon binding to its receptor, IL-5 activates the JAK/STAT and MAPK pathways. IL-5 is produced by Th2 cells, eosinophils, and activated mast cells. It functions in the recruitment, activation, proliferation, and survival of eosinophils, thus playing an important role in allergic inflammation, asthma, and parasite immunity. Stimulation of eosinophils with IL-5 leads to their activation, upregulation of CD11b expression, and inhibition of apoptosis (Shearer).