Anti-fms related receptor tyrosine kinase 3 antibodies are used for the immunodetection of the protein encoded by the FLT3 gene. In humans, the canonical protein has a reported length of 993 amino acid residues and a mass of 112.9 kDa. Its subcellular localization is in the ER and membrane. Alternative splicing is reported to yield 2 different isoforms for this protein. It is notably expressed in bone marrow, in hematopoietic stem cells, in myeloid progenitor cells and in granulocyte/macrophage progenitor cells. A member of the Tyr protein kinase protein family, it is reported to be a tyrosine-protein kinase that acts as cell-surface receptor for the cytokine FLT3LG and regulates differentiation, proliferation and survival of hematopoietic progenitor cells and of dendritic cells. Other names for this target antigen include FLK-2, FLK2, STK1, receptor-type tyrosine-protein kinase FLT3, CD135 antigen, and CD135. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.