| First Author | Hoefer MM | Year | 2008 |
| Journal | Mol Immunol | Volume | 45 |
| Issue | 8 | Pages | 2127-37 |
| PubMed ID | 18295335 | Mgi Jnum | J:138371 |
| Mgi Id | MGI:3805076 | Doi | 10.1016/j.molimm.2007.12.015 |
| Citation | Hoefer MM, et al. (2008) Modulation of murine complement receptor type 2 (CR2/CD21) ectodomain shedding by its cytoplasmic domain. Mol Immunol 45(8):2127-37 |
| abstractText | Ectodomain shedding is a mechanism that regulates numerous functions of cell surface proteins. The extracellular domain of the human complement receptor 2 (CR2/CD21) is released by proteolytic cleavage as a soluble protein through a variety of stimuli including the thiol antioxidants N-acetylcysteine (NAC) and glutathione (GSH), and the oxidant pervanadate (PV). In addition, PV mimics B cell antigen receptor (BCR) signaling. Here, we show that murine CD21 is shed upon those stimuli and that the cytoplasmic domain is an important modulator for CD21-shedding. B cells expressing a mutant CD21 cytoplasmic domain with only three amino acids (KHR) showed increased CD21-shedding and required lower stimuli concentrations. At lower PV concentrations, wildtype CD21 was up-regulated on the cell surface, whereas at higher PV concentrations the ectodomain was shed. These findings further indicate that GSH and NAC utilize different pathways than PV to activate CD21-shedding. Altogether, as pre-activated B cells express higher CD21 levels than resting mature B cells or fully activated and antigen-experienced B cells, we suggest CD21-shedding to be a mechanism to fine-tune B cell activation. |
