• Species Reactivity

  Human

• Specificity

  Detects human SR‑AI/MSR in direct ELISAs and Western blots. In direct ELISAs and Western blots, no cross-reactivity with recombinant mouse SR-AI is observed.

• Source

  Monoclonal Mouse IgG2b Clone # 351615

• Immunogen

  Mouse myeloma cell line NS0-derived recombinant human SR‑AI/MSR    
  Lys77-Leu451    
  Accession # P21757

• Formulation

  Supplied 0.2 mg/mL in a saline solution containing BSA and Sodium Azide.

• Label

  Alexa Fluor 405

Applications

• 
  

  Recommended    
  Concentration

  Sample

• Flow Cytometry

  0.25-1 µg/10    ⁶ cells

  THP‑1 human acute monocytic leukemia cell line treated with PMA and Ca    ²⁺ ionomycin

• 
  

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

Preparation and Storage

• Shipping

  The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.

• Stability & Storage

  Store the unopened product at 2 - 8 °C. Do not use past expiration date.

Background: SR-AI/MSR

The type I class A macrophage scavenger receptor (SR-AI; also MSR-AI) is a 70-80 kDa protein that belongs to the scavenger receptor superfamily (1‑3). Receptors of this family contain characteristic extracellular domains and bind to a series of generally unrelated, but negatively-charged/polyanionic ligands (1, 3). Human SR-AI is a type II transmembrane glycoprotein that is 451 amino acids (aa) in length. It contains a 50 aa cytoplasmic tail, a 26 aa transmembrane segment and a 375 aa extracellular region (4, 5). The extracellular region contains four definitive domains, with a membrane proximal spacer of 33 aa, an alpha -helical coiled-coil domain of 163 aa, a collagen-like domain of 69 aa, and a cysteine-rich C-terminus of 110 aa (4, 6). The cysteine-rich domain (CRD) forms three intrachain disulfide bonds (7). The functional form of the molecule is a 220‑230 kDa membrane-associated trimer that, in human, apparently has two disulfide bonded chains and a third noncovalently associated subunit (8, 9). Human extracellular region is 73% and 72% aa identical to bovine and mouse SR-AI extracellular region, respectively. The human gene for SR-A gives rise to three isoforms; the I isoform of 451 aa, the II isoform of 358 aa, and the III isoform of 388 aa (4, 5, 10). All are identical through the first 344 aa which includes the cytoplasmic tail through the collagenous domain. Isoform II (SR-AII) shows a severe truncation of the CRD, but is expressed on the cell surface. Isoform III (SR-AIII) has a modest truncation of the CRD, and cannot be expressed on the cell surface. However, relative to SR-AI, SR-AII is known to show differential sensitivity to LPS and receptor binding to gram‑negative bacteria (9, 11), while SR-AIII is known to be a dominant-negative isoform (10). SR-AIII may achieve this by either heterotrimerizing with SR-AI, or simply eliminating the production of SR-AI mRNA.

• References:

1. Platt, N. and S. Gordon (2001) J. Clin. Invest. 108:649.

2. Linton, M.F. and S. Fazio (2001) Curr. Opin. Lipidol. 12:489.

3. Platt, N. and S. Gordon (1998) Chem. Biol. 5:R193.

4. Matsumoto, A. et al. (1990) Proc. Natl. Acad. Sci. USA 87:9133.

5. Emi, M. et al. (1993) J. Biol. Chem. 268:2120.

6. Naito, M. et al. (1992) Am. J. Pathol. 141:591.

7. Resnick, D. et al. (1996) J. Biol. Chem. 271:26924.

8. Ashkenas, J. et al. (1993) J. Lipid Res. 34:983.

9. Penman, M. et al. (1991) J. Biol. Chem. 266:23985.

10. Gough, P.J. et al. (1998) J. Lipid Res. 39:531.

11. Peiser, L. et al. (2000) Inf. Immun. 68:1953.

• Long Name:

  Macrophage Scavenger Receptor Types I and II

• Entrez Gene IDs:

  4481 (Human); 20288 (Mouse); 25073 (Rat)

• Alternate Names:

  CD204 antigen; CD204; Macrophage acetylated LDL receptor I and II; macrophage scavenger receptor 1; macrophage scavenger receptor type III; MSR1; phSR1; phSR2; SCARA1; SCARA1macrophage scavenger receptor types I and II; Scavenger receptor class A member 1; scavenger receptor class A, member 1; SR-A; SRAI; SR-AI