Requirement for B Cell Linker Protein (BLNK) in B Cell Development

Abstract

Linker proteins function as molecular scaffolds to localize enzymes with substrates. In B cells, B cell linker protein (BLNK) links the B cell receptor (BCR)–activated Syk kinase to the phosphoinositide and mitogen-activated kinase pathways. To examine the in vivo role of BLNK, mice deficient in BLNK were generated. B cell development in BLNK ^−/− mice was blocked at the transition from B220⁺CD43⁺ progenitor B to B220⁺CD43⁻ precursor B cells. Only a small percentage of immunoglobulin M⁺⁺ (IgM⁺⁺), but not mature IgM^loIgD^hi, B cells were detected in the periphery. Hence, BLNK is an essential component of BCR signaling pathways and is required to promote B cell development.