HGAL within lipid rafts enhances BCR signaling. (A) In resting B cells, HGAL is mainly located within lipid rafts together with Lyn. (B) In BCR-stimulated B cells, Lyn phosphorylates tyrosine residues within the ITAMs of CD79a/b, and this attracts and activates Syk. Coassociation of Syk with HGAL enhances Syk kinase activity and BCR signaling strength. Following BCR engagement, HGAL is shunted from lipid rafts to ultimately end up in the cell cytoplasm for destruction by the proteasome. Professional illustration by Patrick Lane, ScEYEnce Studios.