Stimulates the proliferation of mast cells. Able to augment the proliferation of both myeloid and lymphoid hematopoietic progenitors in bone marrow culture. Mediates also cell-cell adhesion. Acts synergistically with other cytokines, probably interleukins (By similarity). Homodimer, non-covalently linked. Also exists as a secreted soluble form (isoform 1 only). A soluble form is produced by proteolytic processing of isoform 1 in the extracellular domain. Belongs to the SCF family.