Sialomucin that may play a key role in hematopoiesis. May be involved in cell adhesion. Promotes myogenesis by enhancing CXCR4-dependent cell motility. Positively regulates myoblast migration and promotes myoblast fusion into myotubes (By similarity). Interacts with CXCR4. Highly N- and O-glycosylated; contains sialic acid. Belongs to the CD164 family.