Binds to the 60S ribosomal subunit and prevents its association with the 40S ribosomal subunit to form the 80S initiation complex in the cytoplasm. May also be involved in ribosome biogenesis. Monomer. Associates with the 60S ribosomal subunit. Shuttles between cytoplasm and nucleus/nucleolus. Belongs to the eIF-6 family. Extended N-terminus.