NMD3 Homolog (NMD3)

Treatment of transfected HeLa cells with leptomycin B, an inhibitor of CRM1-mediated nuclear export, strongly increased accumulation of NMD3 in nuclei and nucleoli, suggesting that NMD3 shuttles between the cytoplasm and nucleus in a CRM1-dependent manner.

Mutant forms of NMD3 containing substitutions in the NES domain showed reduced export to the cytoplasm in Xenopus oocytes. Depletion of the nuclear RAN-GTP pool also reduced export of NMD3 to the cytoplasm, indicating that NMD3 export is RAN-GTP dependent. NMD3 associated with 60S subunits in both nuclear and cytoplasmic extracts of Xenopus oocytes, but not with 40S or 80S subunits. NES-defective NMD3 mutants acted as dominant-negative inhibitors of 60S subunit export.