Biolegend, 561014, Biotinylated Recombinant Human SIRPα-Fc Chimera (carrier-free), 25μg

Signal Regulatory Proteins (SIRPs) are a family of transmembrane glycoproteins with extracellular IgG domains. SIRPα is an inhibitory receptor expressed on neurons and myeloid cells, including macrophages, granulocytes, myeloid dendritic cells, mast cells, and their precursors (including hematopoietic stem cells). The extracellular regions of the SIRPs are comprised of three Ig-like loops; the proximal loops contain IgC domains, whereas the distal membrane loop contains an IgV domain. While these extracellular domains are similar to SIRPs, their transmembrane and cytoplasmic domains differentiate them from one another. The C-terminal intracellular domains of the SIRPα subfamily contain a relatively long amino acid sequence that includes four tyrosine residues to form two immunoreceptor tyrosine-based inhibition motifs (ITIM). SIRPα is best known for its inhibitory role following its interaction with the widely distributed protein CD47 (on host target cells). CD47 is a “marker of self”, which upon binding to SIRPα signals against phagocytosis by macrophages expressing SIRPα. When CD47 binds the N-terminal IgG domain of SIRPα, this causes clustering and phosphorylation of SIRPα. SIRPα phosphorylation results in the recruitment and activation of the tyrosine phosphatases SHP-1 and SHP-2, which regulate cellular functions in a negative fashion, including the regulation of leukocyte adhesion and transmigration, T cell activation, macrophage fusion, and phagocytosis. In addition to its role in "self-signaling", SIRPα also functions as a scaffold for membrane-bound signaling molecules, plays a role in macrophage and osteoclast fusion, regulates T cell/DC activation, and controls myeloid cell migration.
25μg
Source: Biotinylated recombinant human SIRPA, amino acid (Glu31-Arg370) (Accession # P78324.2), with a linker, a C-terminal Human IgG (Pro100-Lys330), and an Avi-tag was site-specifically biotinylated by the enzyme BirA, was expressed in 293E.
Molecular Mass: The 592 amino acid recombinant protein has a predicted molecular mass of approximately 65.8 kD. The DTT-reduced protein migrates at approximately 75 - 115 kD, and the non-reduced protein migrates at approximately 140 – 240 kD by SDS-PAGE. The predicted N-terminal amino acid is Glu.
Purity: > 95%, as determined by Coomassie-stained SDS-PAGE.
Formulation: 0.22 µm filtered protein solution is in PBS, 5 % Glycerol, pH 7.4.
Endotoxin Level: Less than 0.1 EU per µg cytokine as determined by the LAL method
Concentration: 25 µg size is bottled at 200 µg/mL. 100 µg size and larger sizes are lot-specific and bottled at the concentration indicated on the vial. To obtain lot-specific concentration and expiration, please enter the lot number in our Certificate of Analysis online tool.
Storage & Handling: Unopened vial can be stored between 2°C and 8°C for up to 2 weeks, at -20°C for up to six months, or at -70°C or colder until the expiration date. For maximum results, quick spin vial prior to opening. The protein can be aliquoted and stored at -20°C or colder. Stock solutions can also be prepared at 50 - 100 µg/mL in appropriate sterile buffer, carrier protein such as 0.2 - 1% BSA or HSA can be added when preparing the stock solution. Aliquots can be stored between 2°C and 8°C for up to one week and stored at -20°C or colder for up to 3 months. Avoid repeated freeze/thaw cycles.
Activity: When recombinant human CD47 (Cat. No. 785406) is immobilized at 1 µg/mL, biotinylated recombinant human SIRPα binds in a dose-dependent manner with an ED50 range of 4 – 24 ng/mL. HRP-Avidin (Cat. No. 405103) was used to detect the binding.
Application: Biossay
Application Notes: BioLegend carrier-free recombinant proteins provided in liquid format are shipped on blue-ice. Our comparison testing data indicates that when handled and stored as recommended, the liquid format has equal or better stability and shelf-life compared to commercially available lyophilized proteins after reconstitution. Our liquid proteins are validated in-house to maintain activity after shipping on blue ice and are backed by our 100% satisfaction guarantee. If you have any concerns, contact us at [email protected].
Structure: Disulfide-linked homodimer
Distribution: Broadly distributed in normal adult tissues including brain, endocrine tissues, bone marrow/immune system, lung, pancreas, gastrointestinal tract, kidney, testis, and ovary
Function: An inhibitory receptor is present in myeloid cells. It interacts with the widely distributed membrane protein CD47 to prevent the phagocytosis of healthy cells.
Interaction: Interacts with CD47-expressing cells throughout the body
Ligand/Receptor: CD47
Bioactivity: Measured by immobilized recombinant human CD47 binding biotinylated recombinant human SIRPα in a dose-dependent manner.
Cell Type: Macrophages, Neurons
Biology Area: Cell Adhesion, Innate Immunity, Neuroscience
Molecular Family: Adhesion Molecules, Soluble Receptors
Antigen References: van Beek EM, et al. 2005. J Immunol. 12:7781-7. Lee WY, et al. 2007. J Immunol. 11:7741–50. Subramanian S, eet al. 2006. Blood. 107: 2548-56. Barclay AN. 2009. Current Opinion in Immunology. 21:47-52. Liu Y, et al. 2005. J Biol Chem. 43:36132-40.
Gene ID: 140885
UniProt: View information about SIRPalpha on UniProt.org
Regulatory Status: RUO
Other Names: Human SIRPa, SI, SIRPA, SIRPalpha, CD172a, BIT, MacrophageFusion Receptor, MFR, P84, MYD-1, SHP substrate 1, SHPS1, PTPNS1