Leptomycin B

Leptomycin B is an anti-fungal antibiotic, anti-tumor cytotoxin that inhibits CRM1-dependent, NES-dependent nucleo-cytoplasmic translocation (nuclear export inhibitor). NES containing proteins include HIV-1 REV; actin, c-Abl, cyclin B1, MDM2/p53, I?B, MPF, PKA and MEK.

Leptomycin B is an unsaturated, branched-chain fatty acid, and is an important tool in the study of nuclear export. Leptomycin B is a specific inhibitor of proteins containing nuclear export signal. Leptomycin B inhibits nucleo-cytoplasmic translocation of molecules such as the HIV-1 Rev protein and Rev-dependent export of mRNA. The addition of very small amounts to fibroblasts causes accumulation of MEK in the nucleus. Other proteins that are influenced by leptomycin B are actin, c-Abl, cyclin B1, MDM2/p53, IκB, MPF, and PKA. The suggested inhibition mechanism involves the direct binding of leptomycin B to CRM1, which blocks the binding of CRM1 to proteins containing the nuclear export signal, via the interaction with cysteine residue in CRM1 control conserved region.

Supply conditions do not apply to the regions and states of Brazil: North, Northeast, Mato Grosso do Sul, Mato Grosso, and Rio Grande do Sul.