| First Author | Mielenz D | Year | 2005 |
| Journal | J Immunol | Volume | 174 |
| Issue | 6 | Pages | 3508-17 |
| PubMed ID | 15749887 | Mgi Jnum | J:97708 |
| Mgi Id | MGI:3576160 | Doi | 10.4049/jimmunol.174.6.3508 |
| Citation | Mielenz D, et al. (2005) Lipid rafts associate with intracellular B cell receptors and exhibit a B cell stage-specific protein composition. J Immunol 174(6):3508-17 |
| abstractText | Lipid rafts serve as platforms for BCR signal transduction. To better define the molecular basis of these membrane microdomains, we used two-dimensional gel electrophoresis and mass spectrometry to characterize lipid raft proteins from mature as well as immature B cell lines. Of 51 specific raft proteins, we identified a total of 18 proteins by peptide mass fingerprinting. Among them, we found vacuolar ATPase subunits alpha-1 and beta-2, vimentin, gamma-actin, mitofilin, and prohibitin. None of these has previously been reported in lipid rafts of B cells. The differential raft association of three proteins, including a novel potential signaling molecule designated swiprosin-1, correlated with the stage-specific sensitivity of B cells to BCR-induced apoptosis. In addition, MHC class II molecules were detected in lipid rafts of mature, but not immature B cells. This intriguing finding points to a role for lipid rafts in regulating Ag presentation during B cell maturation. Finally, a fraction of the BCR in the B cell line CH27 was constitutively present in lipid rafts. Surprisingly, this fraction was neither expressed at the cell surface nor fully O-glycosylated. Thus, we conclude that partitioning the BCR into lipid rafts occurs in the endoplasmic reticulum/cis-Golgi compartment and may represent a control mechanism for surface transport. |
