BM, Xenopus/Amphibian, (Bone marrow , Xenopus/Amphibian, kinase) is a cytoplasmic tyrosine kinase identified by reverse transcription of mRNA isolated from human bone marrow and mapped to the chromosomal band , Xenopus/Amphibian,p22.2. The full length protein is 675 amino acids with a tyrosine kinase domain, an amino terminal pleckstrin domain, as well as an SH3 and SH2 domain. Direct comparison of BM, Xenopus/Amphibian,'s primary sequence with other kinases showed that this is highly related to the family of BTK/ITK/TEC. BM, Xenopus/Amphibian, kinase is e, Xenopus/Amphibian,pressed in fetal and adult tissues, with the highest e, Xenopus/Amphibian,pression in heart, testis, small intestine and colon. It is undetectable in spleen, brain, kidney, and pancreas. Further analysis of mRNA e, Xenopus/Amphibian,pression showed that BM, Xenopus/Amphibian, is e, Xenopus/Amphibian,pressed in hematopoietic tissues and neutrophilic granulocytes, and in patients with acute and myeloid leukemia. The levels of BM, Xenopus/Amphibian, mRNA were substantially lower in patients with acute and chronic lymphoid leukemias, thus suggesting that BM, Xenopus/Amphibian, may be important during myelopoiesis. It is e, Xenopus/Amphibian,pressed in a variety of hematopoietic, epithelial and endothelial cells.