• Species Reactivity

  Human

• Specificity

  Detects human Klotho in direct ELISAs. In direct ELISAs, approximately 50% cross-reactivity with recombinant mouse (rm) Klotho (aa 35-982) is observed and no cross-reactivity with rmKlotho (aa 23-550), recombinant human (rh) Klotho beta (aa 53-997), or rhCytosolic beta‑Glucosidase/GBA3 is observed.

• Source

  Monoclonal Rat IgG    _2B Clone # 775340

• Purification

  Protein A or G purified from hybridoma culture supernatant

• Immunogen

  Mouse myeloma cell line NS0-derived recombinant human Klotho    
  Glu34-Ser981    
  Accession # Q9UEF7

• Formulation

  Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied as a 0.2 µm filtered solution in PBS.

• Endotoxin Level

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

• Label

  Unconjugated

Applications

• Recommended    
  Concentration

  Sample

• Neutralization

  Measured by its ability to neutralize Klotho-induced proliferation in the BaF3 mouse pro‑B cell line transfected with human FGF RIIIc. The Neutralization Dose (ND    ₅₀) is typically 0.15-0.6 ug/mL in the presence of 0.3 ug/mL Recombinant Human Klotho.

Please Note: Optimal dilutions should be determined by each laboratory for each application.  are available in the Technical Information section on our website.

Data Examples

Preparation and Storage

• Reconstitution

  Sterile PBS to a final concentration of 0.5 mg/mL.

• Shipping

  The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C

• Stability & Storage

  Use a manual defrost freezer and avoid repeated freeze-thaw cycles.    

• 12 months from date of receipt, -20 to -70 °C as supplied.

• 1 month, 2 to 8 °C under sterile conditions after reconstitution.

• 6 months, -20 to -70 °C under sterile conditions after reconstitution.

Background: Klotho

Klotho, also called Klotho-alpha, is the founding member of the Klotho family within the glycosidase-1 superfamily (1, 2). Klotho is expressed in areas concerned with calcium regulation, predominantly in the kidney distal convoluted tubules, but also in the brain choroid plexus (which produces cerebrospinal fluid) and the parathyroid (1). The 1012 amino acid (aa) type I transmembrane protein contains a 32 aa signal sequence, a 948 aa extracellular domain (ECD) containing two extracellular glycosidase-like domains, a 21 aa transmembrane domain and an 11 aa intracellular domain. Within the ECD, human Klotho shares 87%, 90%, 90% and 86% aa identity with mouse, rat, bovine and equine Klotho, respectively. Although a truncated 549 aa isoform predicts a soluble 70 kDa form, the form found in plasma and cerebrospinal fluid is a 130 kDa form produced by proteolytic cleavage of the glycosylated 135 kDa full-length Klotho (3, 4). A prominent intracellular 120 kDa form of Klotho is localized to endoplasmic reticulum and Golgi membranes (4). Klotho is named for the Greek goddess who spins the thread of life. The phenotype of Klotho‑deficient mice resembles premature aging, including arteriosclerosis, osteoporosis, skin atrophy, infertility, emphysema and premature death (2). Conversely, excess Klotho extends lifespan (5). Klotho acts as a cofactor for interaction of FGF23 with FGF R1 (6). This interaction negatively regulates 1 alpha -hydroxylase, the rate‑limiting enzyme in the synthesis of 1,25(OH)  ₂D  ₃ (vitamin D)(7). Klotho‑deficient mice show severe hyperphosphatemia and ectopic calcification of soft tissues due to excess vitamin D (2, 7). Both Klotho and Klotho-beta are cofactors for FGF19 binding (8). Klotho also shows glucuronidase activity which activates the renal ion channel TRPV5 to reabsorb urinary calcium (9). Klotho has been reported to downregulate insulin or IGF-1 signaling in adipocytes, to bind and antagonize Wnt molecules, and to facilitate release of parathyroid hormone (10-12).

• References:

1. Nabeshima, Y. (2006) Sci. Aging Knowl. Environ. 8:pe11.

2. Kuro-o, M. et al. (1997) Nature 390:45.

3. Shiraki-Iida, T. et al. (1998) FEBS Lett. 424:6.

4. Imura, A. et al. (2004) FEBS Lett. 565:143.

5. Kurosu, H. et al. (2005) Science 309:1829.

6.  Kurosu, H. et al. (2006) J. Biol. Chem. 281:6120.

7. Tsujikawa, H. et al. (2003) Mol. Endocrinol. 17:2393.

8. Wu, X. et al. (2007) J. Biol. Chem. 282:29069.

9. Chang, Q. et al. (2005) Science 310:490.

10. Yamamoto, M. et al. (2005) J. Biol. Chem. 280:38029.

11. Liu, H. et al. (2007) Science 317:803.

12. Imura, A. et al. (2007) Science 316:1615.

• Entrez Gene IDs:

  9365 (Human); 16591 (Mouse)

• Alternate Names:

  EC 3.2.1; EC 3.2.1.31; KL; Klotho