The B cell antigen receptor (BCR) includes an Igα/Igβ heterodimer non-covalently associated with surface immunoglobulin. Recently, variant Igα and Igβ transcripts, arising from alternative mRNA splicing, have been reported. The present study examined the function of the potential products of these transcripts, by utilizing cDNA expression plasmids to reconstitute human BCR expression in transfected 293T cells. Spliced transcripts produced truncated proteins (Δlgα and Δlgβ), that failed to form heterodimers with their full-length counterparts, and did not mediate transport of IgM to the cell surface. When overexpressed, both Δlgα and Δlgβ acted as competitors of Igα and Igβ, leading to down-modulated surface IgM expression, and retention of IgM in the endoplasmic reticulum. These findings document a possible novel mechanism for controlling BCR expression in B cells, based on up-regulated synthesis of components devoid of transport function.
|Number of pages||11|
|Journal||European Journal of Immunology|
|Publication status||Published - 2002|
- B cell receptor
ASJC Scopus subject areas