• Purity

  >97%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

  <0.01 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured in a serum-free cell proliferation assay using MCF‑7 human breast cancer cells. Karey, K.P.     et al. (1988) Cancer Research     48:4083. The ED    ₅₀ for this effect is 10‑50 ng/mL.

• Source

  E. coli-derived Ser177-Lys241

• Accession #

• N-terminal Sequence    
  Analysis

  Ser177

• Predicted Molecular Mass

  7 kDa

• SDS-PAGE

  8 kDa, reducing conditions

Carrier Free

What does CF mean?

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.

What formulation is right for me?

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: Neuregulin-1 alpha/NRG1 alpha

The neuregulin family of structurally related glycoproteins comprises products from four distinct but related genes, Nrg-1, Nrg-2, Nrg-3, and Nrg-4. Through alternative splicing or the use of alternative promoters, Nrg-1 encodes more than 14 soluble or transmembrane proteins. The extracellular domain of the transmembrane NRG1 isoforms can be proteolytically cleaved to release soluble growth factors. The alpha - or  beta -splice variants differ in their C-terminal region. All NRG1 isoforms contain an EGF-like domain that is required for their direct binding to the ErbB3 or ErbB4 receptor tyrosine kinases. The ErbB3 or ErbB4 subsequently recruits and heterodimerizes with ErbB2, resulting in tyrosine phosphorylation and NRG1 signaling. NRG1 isoforms can be classified into three major subtypes. Type I (Neu Differentiation Factor, NDF; Heregulin, HRG; Acetylcholine Receptor Inducing Activity, ARIA) and type II (Glial Growth Factor, GGF). NRG1s have an immunoglobulin (Ig)-like domain N-terminal to the EGF-like domain. Type I NRG1s differ from type II NRG1s by having a glycosylation-rich domain between the Ig-like and the EGF-like domains. Type III NRG1 (Sensory and Motor neuron-Derived Factor) lacks the Ig-like domain but has a cysteine rich domain (CRD) instead. NRG1 isoforms show distinct spatial and temporal expression patterns. These proteins play important roles during development of both the nervous system and the heart. They have been shown to regulate the selective expression of neurotransmitter receptors in neurons and at the neuromuscular junction, and to promote the differentiation and development of Schwann cells from neural crest stem cells. NRG1s have also been shown to be involved in the establishment of the oligodendroglial lineage.

• References:

1. Lemke, G. (2006) Science STKE 325:pe11.

2. Esper, R.M. et al. (2006) Brain Res. Brain Res. Rev. 51:161.

3. Tosato, S. et al. (2005) Schizophr. Bull. 31:613.

• Entrez Gene IDs:

  3084 (Human); 211323 (Mouse); 112400 (Rat)

• Alternate Names:

  ARIA; GGF2; HGL; HRG; HRG1; MST131; MSTP131; neuregulin 1; Neuregulin1 alpha; Neuregulin-1 alpha; pro-neuregulin-1, membrane-bound isoform; pro-NRG1; sensory and motor neuron derived factor; SMDF