Myo1e modulates the recruitment of activated B cells to inguinal lymph nodes

Abstract

The inclusion of lymphocytes in high endothelium venules and their migration to the lymph nodes are critical steps in immune response. Cell migration is regulated by actin cytoskeleton and myosins. Myo1e is a long-tailed class I myosin and is highly expressed in B cells that have not been studied in the context of cell migration. By using intravital microscopy in an in vivo model and performing in vitro experiments, we studied the relevance of Myo1e for the adhesion and inclusion of activated B cells in high endothelial venules. We observed a reduced expression of integrins and F-actin in the membrane protrusions of B lymphocytes, which might be explained by deficiencies in vesicular trafficking. Interestingly, the lack of Myo1e reduced the phosphorylation of focal adhesion kinase (FAK), AKT, and RAC-1, disturbing the FAK/PI3K/RAC-1 signaling pathway. Taken together, our results indicate critical role of Myo1e in the mechanism of B cell adhesion and migration.