LIM homeobox protein 1 is a potential transcription factor that may play a role in differentiation and development of neural and lymphoid cells. It contains 1 homeobox DNA-binding domain and 2 LIM zinc-binding domains. The latter have a negative regulatory function and disruption of the LIM domains results in an activated form. It localises to the nucleus and is expressed in the brain, thymus and tonsils. It is also expressed in samples from patients with chronic myeloid leukemia and in 58% of acute myeloid leukemia cell lines.