Shows growth cone collapsing activity on dorsal root ganglion (DRG) neurons in vitro. May be a stop signal for the DRG neurons in their target areas, and possibly also for other neurons. May also be involved in the maintenance and remodeling of neuronal connections. Ligand of TREM2 with PLXNA1 as coreceptor in dendritic cells, plays a role in the generation of immune responses and skeletal homeostasis (By similarity). . This is the function of Ensembl gene identifier ENSG00000137872 (SEMA6D, semaphorin 6D).