Uncharacterized protein YNL124W; RNA-binding protein required for the maturation of box H/ACA snoRNPs complex and ribosome biogenesis. During assembly of the H/ACA snoRNPs complex, it associates with the complex and disapears during maturation of the complex and is replaced by GAR1 to yield mature H/ACA snoRNPs complex. Acts as a competitive binder for CBF5 probably required to prevent non-cognate RNAs from being loaded during transport of the particle by inducing a non- productive conformation of CBF5 (By similarity) (492 aa)