Identification of a pre-BCR lacking surrogate light chain.
SLP-65-/- pre-B cells show a high proliferation rate in vitro. We have shown previously that lambda5 expression and consequently a conventional pre-B cell receptor (pre-BCR) are essential for this proliferation. Here, we show that pre-B cells express a novel receptor complex that contains a micro heavy chain (microHC) but lacks any surrogate (SL) or conventional light chain (LC). This SL-deficient pre-BCR (SL-pre-BCR) requires Ig-alpha for expression on the cell surface. Anti-micro treatment of pre-B cells expressing the SL-pre-BCR induces tyrosine phosphorylation of substrate proteins and a strong calcium (Ca2+) release. Further, the expression of the SL-pre-BCR is associated with a high differentiation rate toward kappaLC-positive cells. Given that B cell development is only partially blocked and allelic exclusion is unaffected in SL-deficient mice, we propose that the SL-pre-BCR is involved in these processes and therefore shares important functions with the conventional pre-BCR.
Su
Yu-Wen
YW
Institute for Biology III, Albert-Ludwigs University of Freiburg, Max Planck Institute for Immunobiology, Freiburg, Germany.
Flemming
Alexandra
A
Wossning
Thomas
T
Hobeika
Elias
E
Reth
Michael
M
Jumaa
Hassan
H
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation; D007070:Immunoglobulin A / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D011947:Receptors, Antigen, B-Cell / Q000737:chemistry*; D014443:Tyrosine / Q000378:metabolism
D007070:Immunoglobulin A; D011947:Receptors, Antigen, B-Cell; D014443:Tyrosine; D002118:Calcium