Ribosome hibernation factor; regulates ribosome homeostasis, coupling biosynthesis and degradation in response to nutrient availability; nucleolar role promoting ribosome biogenesis during exponential growth, distinct from a cytosolic role forming dormant 80S ribosomes protected from proteasomal degradation during starvation; influences binding of eEF3 (Yef3p) with ribosomes; inhibits translation after 80S complex formation; binds G4 quadruplex and triplex DNA; role in telomere maintenance