• Purity

  >90%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

  <1.0 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to enhance neurite outgrowth of dissociated E13 chick embryonic dorsal root ganglia (DRG) neurons. Able to significantly enhance neurite outgrowth when immobilized as a 3 µL droplet containing 100 ng on a nitrocellulose-coated microplate.

• Source

  Mouse myeloma cell line, NS0-derived Phe29-Cys807, with a C-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Phe29

• Predicted Molecular Mass

  88.9 kDa

• SDS-PAGE

  110-115 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: F-Spondin/SPON1

F-Spondin (floor plate and thrombospondin homology), also called Spondin-1, SPON1 or VSGP (vascular smooth muscle growth-promoting factor), is an approximately 110 kDa secreted glycoprotein that is a member of a subgroup of TSR (thrombospondin) molecules that are either membrane-bound or associated with the extracellular matrix (ECM) (1-3). Human F-Spondin is synthesized as an 807 amino acid (aa) precursor with a 779 aa mature region that includes an N-terminal reelin‑like domain, an F-spondin (FS) domain, and six C‑terminal thrombospondin (TSP) type I repeats (1-3). Mature human F-Spondin shares 97%, 97%, 98% and 99% aa sequence identity with mouse, rat, bovine and canine F-Spondin, respectively.  TSP 5 and 6 bind ECM, while TSP 1-4 plus the FS domain may mediate repulsive activity on motor neurons and outgrowth promoting activity on sensory neurons during development or after injury (2-5). Crystal structure indicates that the reelin-like domain binds heparin and may mediate weak dimerization (6). Plasmin cleavage generates a diffusible 95 kDa, 656 aa F-spondin that lacks TSP 5 and 6, while non‑plasmin cleavage between the FS segment and the first TSP repeat generates 60 kDa and 50 kDa fragments (3, 4, 7). F-Spondin shows unusual C‑mannosylation and O-fucosylation within the TSP repeats (3). Mammalian cells expressing F-spondin include floor plate epithelium, ventral motor neurons, Schwann cells, fibroblasts, hippocampal pyramidal cells, endothelial cells, vascular smooth muscle cells and some tumor cells (2-5, 8). F-Spondin can either tether cells to the ECM or interfere with integrin adhesion, thus either blocking or allowing nerve or vascular endothelial cell migration (3, 9). It binds beta -amyloid fibrils and inhibits beta ‑secretase cleavage, thus reducing A beta plaque deposition associated with Alzheimer’s disease (10, 11). F-Spondin is also reported to inhibit differentiation or migration during angiogenesis (affecting endothelial cells) and bone development (affecting osteoclast and chondrocyte precursors) (3, 9, 12, 13).

• References:

1. Miyamoto, K. et al. (2001) Arch. Biochem. Biophys. 390:93.

2. Klar, A. et al. (1992) Cell 69:95.

3. Feinstein, Y. and A. Klar (2004) Int. J. Biochem. Cell Biol. 36:975.

4. Burstyn-Cohen, T. et al. (1998) J. Neurosci. 18:8875.

5. Feinstein, Y. et al. (1999) Development 126:3637.

6. Tan, K. et al. (2008) J. Mol. Biol. 381:1213.

7. Tzarfaty-Majar, V. et al. (2001) J. Biol. Chem. 276:28233.

8. Pyle-Chenault, R.A. et al. (2005) Tumor Biol. 26:245.

9. Terai, Y. et al. (2001) J. Cell Physiol. 188:394.

10. Ho, A. and T.C. Sudhof (2004) Proc. Natl. Acad. Sci. USA 101:2548.

11. Hafez, D.M. et al. (2012) Neuroscience 223:465.

12. Palmer, G.D. et al. (2010) J. Orthop. Res. 28:1323.

13. Oka, H. et al. (2011) J. Periodontol. 82:1776.

• Entrez Gene IDs:

  10418 (Human); 233744 (Mouse); 64456 (Rat)

• Alternate Names:

  FSpondin; F-Spondin; KIAA0762VSGP/F-spondin; MGC10724; SPON1; spondin 1, (f-spondin) extracellular matrix protein; spondin 1, extracellular matrix protein; spondin-1; Vascular smooth muscle cell growth-promoting factor; VSGP