Ribosome-binding protein involved in ribosome hibernation, a process during which ribosomes are stabilized in an inactive state and preserved from proteasomal degradation. Acts via its association with eiF5a (eif5a and eif5a2) at the polypeptide exit tunnel of the ribosome, preventing mRNA translation. Involved in ribosome hibernation in the mature egg by preventing mRNA translation, leading to ribosome inactivation. Ribosomes, which are produced in large quantities during oogenesis, are stored and translationally repressed in the egg and early embryo. Compared to dap1b, binds and inactivates ribosomes less efficiently