Functions as a cell surface repellent for mossy fibers of developping neurons in the hippocampus where it plays a role in axon guidance. May function through the PLXNA4 receptor expressed by mossy cell axons. (Microbial infection) Acts as a receptor for P.sordellii toxin TcsL in the in the vascular endothelium. (Microbial infection) Interacts with P.sordellii toxin TcsL; semaphorins SEMA6A and SEMA6B constitute the major host receptors for TcsL in the vascular endothelium. Expressed in the brain in GABAergic neurons. The disease is caused by variants affecting the gene represented in this entry. Belongs to the semaphorin family. Aberrant splicing.