The lack of WIP binding to actin results in impaired B cell migration and altered humoral immune responses
journal contributionposted on 20.08.2020, 16:42 by Selina Jessica Keppler, Marianne Burbage, Francesca Gasparrini, Lara Hartjes, Shweta Aggarwal, Michel J Massaad, Raif S Geha, Andreas Bruckbauer, Facundo D Batista
Wiskott-Aldrich syndrome protein (WASp) is a main cytoskeletal regulator in B cells. WASp-interacting protein (WIP) binds to and stabilizes WASp but also interacts with actin. Using mice with a mutated actin binding domain of WIP (WIPΔABD), we here investigated the role of WIP binding to actin during B cell activation. We found an altered differentiation of WIPΔABD B cells and diminished antibody affinity maturation after immunization. Mechanistically, WIPΔABD B cells showed impaired B cell receptor (BCR)-induced PI3K signaling and actin reorganization, likely caused by diminished CD81 expression and altered CD19 dynamics on the B cell surface. WIPΔABD B cells displayed reduced in vivo motility, concomitantly with impaired chemotaxis and defective F-actin polarization, HS1 phosphorylation, and polarization of HS1 to F-actin-rich structures after CXCL12 stimulation in vitro. We thus concluded that WIP binding to actin, independent of its binding to WASp, is critical for actin cytoskeleton plasticity in B cells.
B lymphocytesCXCR4HS1PI3K signalingWiskott-Aldrich syndromeactin cytoskeletonchemotaxisActinsAnimalsAntibody AffinityAntigens, CDB-LymphocytesCarrier ProteinsCell MembraneCell MovementCell PolarityChemotaxisCytoskeletal ProteinsDiffusionGerminal CenterGranulocyte Colony-Stimulating FactorImmunity, HumoralMicePhosphatidylinositol 3-KinasesProtein BindingReceptors, Antigen, B-CellSignal TransductionBatista FC001035BRF-ackFC-ack0601 Biochemistry and Cell Biology