• Purity

  >95%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to inhibit proliferation of mIMCD‑3 mouse epithelial cells. The ED    ₅₀ for this effect is 1.0-4.0 μg/mL.

• Source

  Chinese Hamster Ovary cell line, CHO-derived

  Human Collectrin (Glu15-Pro141) Accession # Q9HBJ8	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Glu15

• Structure / Form

  Disulfide-linked homodimer

• Predicted Molecular Mass

  41 kDa (monomer)

• SDS-PAGE

  54-64 kDa, reducing conditions

Background: Collectrin

Collectrin, also known as TMEM27 and NX‑17, is a 35‑45 kDa transmembrane protein that shows structural similarity to the C‑terminal region of Angiotensin Converting Enzyme 2 (ACE‑2) but lacks peptidase activity (1, 2). Mature human Collectrin consists of a 127 amino acid (aa) extracellular domain (ECD), a 21 aa transmembrane segment, and a 60 aa cytoplasmic domain (3). Within the ECD, human Collectrin shares 87% and 89% aa sequence identity with mouse and rat Collectrin, respectively. Collectrin is expressed as a disulfide‑linked homodimer of variably glycosylated subunits (4‑6). It is highly expressed in the proximal convoluted tubules of renal collecting ducts and inhibits the proliferation of tubule epithelial cells (3, 6‑8). It associates with several amino acid transporters on the luminal surface of these cells, where it is required for the reabsorption of multiple amino acids (7‑9). Collectrin is also expressed in pancreatic islet beta cells and enhances glucose‑stimulated insulin secretion as well as insulin resistance (4, 5, 9, 10). In both the kidney and pancreas, cytoplasmic Collectrin interacts with multiple components of the SNARE complex and other vesicle trafficking proteins (5, 6). A 25 kDa glycosylated fragment of the ECD can be shed from both renal tubule cells and pancreatic beta cells (4, 10). In beta cells, shedding is mediated by BACE2, and the portion left in the membrane can be subsequently cleaved by gamma‑Secretase, releasing the intracellular domain into the cytosol (11). Inhibition of Collectrin shedding from beta cells results in increased beta cell mass and insulin secretion (11).

• References:

1. Lambert, D.W. et al. (2010) Cell. Mol. Life Sci. 67:89.

2. Zhang, Y. and J. Wada (2007) Biochem. Biophys. Res. Commun. 363:1.

3. Zhang, H. et al. (2001) J. Biol. Chem. 276:17132.

4. Akpinar, P. et al. (2005) Cell Metab. 2:385.

5. Fukui, K. et al. (2005) Cell Metab. 2:373.

6. Zhang, Y. et al. (2007) PLoS ONE 5:e414.

7. Danilczyk, U. et al. (2006) Nature 444:1088.

8. Malakauskas, S.M. et al. (2007) Am. J. Physiol. Renal Physiol. 292:F533.

9. Malakauskas, S.M. et al. (2009) Mol. Endocrinol. 23:881.

10. Altirriba, J. et al. (2010) Diabetologia 53:1406.

11. Esterhazy, D. et al. (2011) Cell Metab. 14:365.

• Entrez Gene IDs:

  57393 (Human); 57394 (Mouse); 57395 (Rat)

• Alternate Names:

  Collectrin; kidney-specific membrane protein; NX17; NX-17; TMEM27; transmembrane protein 27NX170610008J07Rik