IGLL5

IGLL5 (Immunoglobulin Lambda Like Polypeptide 5), also known as lambda5, is a core component of the surrogate light chain (SLC) in the pre-B cell receptor (pre-BCR). It pairs with VpreB to form the SLC, which associates with mu heavy chains and Igα/Igβ subunits to enable pre-BCR assembly. This complex is critical for early B cell development, triggering proliferation and differentiation from pro-B to pre-B cells in the bone marrow.
IGLL5 mediates B cell receptor signaling, activating downstream pathways like PI3K-AKT and MAPK. Mutations in IGLL5 are linked to agammaglobulinemia, a primary immunodeficiency characterized by reduced B cells and antibodies. While direct therapeutic targeting of IGLL5 is still emerging, its role in pre-BCR signaling supports research into treatments for B cell malignancies or immunodeficiencies by regulating early B cell maturation.