Recombinant Human Agrin Protein, N-terminal, CF

Recombinant Human Agrin Protein, N-terminal, CF Summary

Product Specifications

Product Datasheets

Carrier Free

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

Background: Agrin

Agrin is a 400-600 kDa heparan sulfate proteoglycan component of the extracellular matrix. The N-terminal half of human Agrin, which mediates ECM interactions, contains a Laminin-binding NtA domain, nine Follistatin-like/Kazal-type protease inhibitor domains, two Laminin EGF-like domains, and one SEA domain. The C-terminal half contains four EGF-like repeats and three Laminin globular G domains. Rat Agrin lacks the NtA domain, and mouse and chick Agrin include the NtA domain only by the use of an alternate promoter. Additional isoforms are generated by alternative splicing at sites Y and Z in the C-terminal half of rat Agrin (known as A and B, respectively in chick). Agrin isoforms that contain an insert at site Z (Z⁺ forms) are known as neural Agrin and are selectively produced by motoneurons. Other isoforms are known as muscle Agrin and are additionally expressed in non-neuronal tissues, particularly in basement membranes of the lung and kidney (1-3). In addition, multiple proteolytic fragments of Agrin are produced by Neurotrypsin, MMP-1, -7, -12, and -14 (4, 5). This recombinant protein consists of the N-terminal region of human Agrin (up to the Neurotrypsin alpha -cleavage site upstream of the SEA domain) (4). It shares 80% amino acid sequence identity with comparable regions of mouse and rat Agrin. The N-terminal region binds to BMP-2, BMP-4, and TGF-beta, and it blocks BMP-induced signaling through BMPR1A (6). The C-terminal half of Z- and Z⁺ Agrin binds to alpha -Dystroglycan and mediates adhesion between motoneurons and myotubes at the neuromuscular junction (NMJ) (7-9). In contrast, only Z⁺ Agrin is effective at inducing clustering of the postsynaptic Acetylcholine Receptor (AChR) and presynaptic motoneuron differentiation (10, 11). Agrin-induced AChR clustering requires a myotube receptor complex that contains alpha -Dystroglycan, MuSK, and LRP4 (7, 12-14). Agrin exhibits many functions in addition to NMJ development. It is enriched in senile Alzheimer’s disease plaques where it binds the A beta (1-40) peptide and promotes amyloid fibril formation (15). It regulates neuronal excitability by binding and inhibiting the alpha 3 subunit of the neuronal Na/K ATPase (16). It functions as an epithelial cell attachment receptor for HIV-1 through interactions with the gp41 coat protein (17). During T cell activation, Agrin contributes to formation of the immunological synapse and regulates the threshold of T cell activation (18). Agrin is up-regulated in hepocellular carcinoma, where it enhances cell proliferation and tumor progression (19).

Related Research Areas

• Extracellular Matrix Molecules
• Proteoglycans
• Synaptic Proteins