The role of paxillin superfamily members- Hic-5 and leupaxin in B cell antigen receptor signaling

Abstract

In our current studies, we showed a novel negative regulatory role of paxillin superfamily members, Hic-5 and leupaxin in BCR signaling pathways. Both Hic-5 and leupaxin are recruited to the B cell membrane and tyrosine phosphorylated upon BCR ligation. We also demonstrated their interaction with Lyn in BCR induced manner which we now believe is the important kinase that phosphorylates both Hic-5 and leupaxin following their recruitment to the B cell membrane upon BCR ligation. Over-expression of either Hic-5 or leupaxin in A20 B cells showed inhibition in BCR signaling pathways specifically in the BCR-induced phosphorylation of JNK and p38 MAPKs but not Erk. With leupaxin overexpression in A20 B cells we also observed inhibition in BCR-induced Akt phosphorylation as well as IL-2 production. In conclusion, we presented a novel inhibitory role of paxillin superfamily members, Hic-5 and leupaxin in BCR signaling pathways.