Myo1e modulates the recruitment of B cells to inguinal lymph nodes

Abstract

The recruitment of leukocyte to high endothelium venules and their migration to the lymph nodes are critical steps to initiate an immune response. Cell migration is regulated by the actin cytoskeleton where myosins have a very import role. Myo1e is a long tail class I myosin highly expressed in B cells that not have been studied in the context of cell migration. By using an in vivo model, through the use of intravital microscopy, we demonstrated the relevance of Myo1e in the adhesion and the migration of B cells in high endothelial venules. These observations were confirmed by in vitro experiments. We also registered a reduction in the expression of integrins and F-actin in the protrusion of B lymphocytes membrane. Deficiencies in vesicular trafficking can explain the decrease of integrins on the surface. Interestingly, Myo1e is associated with focal adhesion kinase (FAK). The lack of Myo1e affected the phosphorylation of FAK and AKT, and the activity of RAC-1, disturbing the FAK/PI3K/RAC-1 signaling pathway. Together, our results indicate critical participation of Myo1e in the mechanism of B cell migration.\n\nSummary statementMyo1e participate in the adhesion and migration in the high endothelial venules by regulation of integrins and the PI3K/FAK/RAC-1 signaling pathway.