The lipid raft microdomain-associated protein reggie-1/flotillin-2 is expressed in human B cells and localized at the plasma membrane and centrosome in PBMCs
- Reggie-1/flotillin-2 is a plasma membrane-associated cytoplasmic protein, which defines non-caveolar raft microdomains. Reggie-1/flotillin-2 is enriched in detergent insoluble (TX100) membrane fractions (DIG), co-localizes with activated GPI-linked proteins and the fyn-kinase in neurons and T cells, and thus apparently participates in the assembly of protein complexes essential for signal transduction. In T cells activated by crosslinking the GPI-linked protein Thy-1 or by crosslinking the ganglioside GM1, reggie-1/flotillin-2 co-localizes with the T cell receptor. To determine whether reggie-1/flotillin-2 is also expressed in B cells, primary B cells from human blood and cell lines representing the developmental stages of pro, pre, mature and plasma B cells were analyzed by Western blotting, RT-PCR and immunofluorescence. Here, we show that reggie-1/flotillin-2 is expressed throughout B cell development, as well as in primary B cells, purified by cell sorting. On non-activated mature B cell Raji cell line we found reggie-1/flotillin-2 are exclusively in the detergent (TX100) insoluble membrane fractions that are staining positive for the raft marker GM1. Immunofluorescence microscopy showed that reggie-1/flotillin-2 is localized at the plasma membrane and marks intracellular spots in PBMCs. Confocal co-localization studies showed that reggie-1/flotillin-2 is associated with the plasma membrane, and the centrosomes (microtubule organizing centers) in these PBMCs. Comparison of reggie-1/flotillin-2 cDNA sequences with the genomic sequence database allowed us to determine the exon/intron structures in mouse and human. The gene organizations are highly conserved suggesting an important function of reggie-1/flotillin-2. Since reggie/flotillin proteins co-cluster with the T cell receptor and fyn kinases upon T cell stimulation, our findings of reggie-1/flotillin-2 in B cells suggest a similar role in B cell function.
Document Type: | Article |
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Language: | English |
Author: | Samuel Solomon, Madhan Masilamani, Lawrence Rajendran, Martin Bastmeyer, Claudia A. O. Stuermer, Harald Illges |
Parent Title (English): | Immunobiology |
Volume: | 205 |
Issue: | 1 |
First Page: | 108 |
Last Page: | 119 |
ISSN: | 0171-2985 |
DOI: | https://doi.org/10.1078/0171-2985-00114 |
PMID: | https://pubmed.ncbi.nlm.nih.gov/11999340 |
Publisher: | Urban & Fischer |
Publication year: | 2002 |
Departments, institutes and facilities: | Institut für funktionale Gen-Analytik (IFGA) |
Dewey Decimal Classification (DDC): | 6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit |
Entry in this database: | 2018/07/25 |