{"product_id":"recombinant-human-cd81-antigen-cd81-partial-bhp10510139","title":"Recombinant Human CD81 antigen (CD81), partial","description":"\u003ch2\u003eOverview\u003c\/h2\u003e \u003cp\u003eRecombinant Human CD81 antigen (CD81), partial is a recombinant protein reagent derived from Homo sapiens (Human) and produced in E.coli. It is commonly used to support Immunology research by enabling binding assays, assay development and protein–protein interaction studies in controlled in vitro settings.\u003c\/p\u003e \u003ch2\u003eKey elements and design rationale\u003c\/h2\u003e\u003cul\u003e \u003cli\u003e\n\u003cstrong\u003eExpressed region:\u003c\/strong\u003e 113-201aa. Region selection can focus on functional domains, improve solubility, or isolate interaction surfaces for targeted studies.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eExpression system:\u003c\/strong\u003e E.coli. Expression host can influence folding and the presence\/absence of post-translational modifications.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eTag \/ fusion:\u003c\/strong\u003e N-terminal 10xHis-tagged and C-terminal Myc-tagged. Tags can support purification and detection; evaluate potential tag effects when studying sensitive interactions.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eMolecular weight (reported):\u003c\/strong\u003e 17.2 kDa. Apparent size may vary with tags, processing, and gel conditions.\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003eWhen comparing results across batches or platforms, interpret signals in the context of construct design (region, tags) and expression host, especially for modification-dependent interactions.\u003c\/p\u003e \u003ch2\u003eBiological background\u003c\/h2\u003e \u003cp\u003eThe gene commonly associated with this target is \u003cstrong\u003eCD81\u003c\/strong\u003e. CD81 refers to a protein target that is studied across multiple biological contexts; annotations and nomenclature can vary by species and isoform. This product corresponds to the Homo sapiens (Human) sequence context, which can be important when comparing homologs or orthologs across model systems. For curated functional annotations, domains, and sequence features, consult primary databases (e.g., UniProt\/NCBI) and the recent literature for the specific organism and isoform.\u003c\/p\u003e \u003ch2\u003eResearch relevance and current trends\u003c\/h2\u003e\u003cul\u003e \u003cli\u003eProfiling immune signaling nodes and cytokine pathways across cell types and activation states.\u003c\/li\u003e \u003cli\u003eStudying ligand–receptor interactions that shape immune cell communication and effector function.\u003c\/li\u003e \u003cli\u003eBuilding quantitative assays to compare pathway modulation by genetic or pharmacologic perturbations.\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003e\u003cstrong\u003eRelevance:\u003c\/strong\u003e Structural component of specialized membrane microdomains known as tetraspanin-enriched microdomains, which act as platforms for receptor clustering and signaling. Essential for trafficking and compartmentalization of CD19 receptor on the surface of activated B cells. Upon initial encounter with microbial pathogens, enables the assembly of CD19-CR2\/CD21 and B cell receptor (BCR) complexes at signaling TERMs, lowering the threshold dose of antigen required to trigger B cell clonal expansion and antibody production. In T cells, facilitates the localization of CD247\/CD3 zeta at antigen-induced synapses with B cells, providing for costimulation and polarization toward T helper type 2 phenotype. Present in MHC class II compartments, may also play a role in antigen presentation. Can act both as positive and negative regulator of homotypic or heterotypic cell-cell fusion processes. Positively regulates sperm-egg fusion and may be involved in acrosome reaction. In myoblasts, associates with CD9 and PTGFRN and inhibits myotube fusion during muscle regeneration. In macrophages, associates with CD9 and beta-1 and beta-2 integrins, and prevents macrophage fusion into multinucleated giant cells specialized in ingesting complement-opsonized large particles. Also prevents the fusion of mononuclear cell progenitors into osteoclasts in charge of bone resorption. May regulate the compartmentalization of enzymatic activities. In T cells, defines the subcellular localization of dNTPase SAMHD1 and permits its degradation by the proteasome, thereby controlling intracellular dNTP levels. Also involved in cell adhesion and motility. Positively regulates integrin-mediated adhesion of macrophages, particularly relevant for the inflammatory response in the lung.\u003c\/p\u003e \u003ch2\u003eCommon research applications\u003c\/h2\u003e\u003cul\u003e \u003cli\u003eAssay and standard development for immunoassays or binding-based detection methods.\u003c\/li\u003e \u003cli\u003eProtein–protein interaction studies (e.g., receptor–ligand or complex assembly) using purified components.\u003c\/li\u003e \u003cli\u003eStructure–function analysis, including domain mapping or evaluation of sequence variants.\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003eIn quantitative assay development, changes in binding or activity readouts are typically interpreted relative to appropriate negative\/positive controls and, where possible, orthogonal assay formats that support the same conclusion.\u003c\/p\u003e \u003ch2\u003eNotes for experimental interpretation\u003c\/h2\u003e\u003cul\u003e \u003cli\u003eRecombinant constructs may represent a defined region (domain) rather than the full-length protein; interpret results in the context of the expressed region.\u003c\/li\u003e \u003cli\u003eTag or fusion elements can aid purification and detection but may influence binding surfaces or oligomerization; consider tag controls when relevant.\u003c\/li\u003e \u003cli\u003eSpecies and isoform differences can affect interaction partners and post-translational modifications; align experimental controls to the intended biological context.\u003c\/li\u003e \u003cli\u003eE. coli expression can limit eukaryotic post-translational modifications; for modification-dependent biology, interpret results accordingly.\u003c\/li\u003e \u003c\/ul\u003e \u003c!-- Sources (internal): - UniProtKB entry for P60033 — UniProt — https:\/\/www.uniprot.org\/uniprotkb\/P60033\/entry - NCBI Gene search (CD81) — NCBI — https:\/\/www.ncbi.nlm.nih.gov\/gene\/?term=CD81 - PubMed search (CD81) — NCBI — https:\/\/pubmed.ncbi.nlm.nih.gov\/?term=CD81 - RCSB PDB search (CD81) — RCSB PDB — https:\/\/www.rcsb.org\/search?query=CD81 - Reactome Pathway Browser — Reactome — https:\/\/reactome.org\/ --\u003e","brand":"CUSABIO TECHNOLOGY LLC","offers":[{"title":"1 mg","offer_id":53065311715693,"sku":"CSB-EP004960HUb1-1MG","price":1812.0,"currency_code":"USD","in_stock":true},{"title":"100 ug","offer_id":53065473917293,"sku":"CSB-EP004960HUb1-100UG","price":419.0,"currency_code":"USD","in_stock":true},{"title":"20 ug","offer_id":53065473950061,"sku":"CSB-EP004960HUb1-20UG","price":224.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0949\/7424\/7277\/files\/CSB-EP004960HUb1-SDS.jpg?v=1772476551","url":"https:\/\/www.ebiohippo.com\/products\/recombinant-human-cd81-antigen-cd81-partial-bhp10510139","provider":"BioHippo","version":"1.0","type":"link"}