Msi2 (musashi homolog 2), also known as MSI2H, is a 328 amino acid protein that localizes to the cytoplasm and contains two RRM (RNA recognition motif) domains. Expressed ubiquitously at low levels, Msi2 functions as an RNA binding protein that, by regulating the expression of target mRNAs, is thought to play a role in the proliferation and maintenance of stem cells within the central nervous system. Msi2 is subject to post-translational phosphorylation and is upregulated in response to brain injury, suggesting a role in healing and brain tissue regeneration. Chromosomal aberrations involving the Msi2 gene are associated with the progression of chronic myeloid leukemia. Multiple isoforms of Msi2 exist due to alternative splicing events.