FBL (fibrillarin) is a catalytic subunit of a multiprotein C/D RNP complex and homologue of S. cerevisiae Nop1 protein. It requires snoRNA to identify the substrate. The core of the complex is made of 15.5kD, Nop56 and Nop58 proteins.
Human fibrillarin forms a sub-complex with splicing factor 2-associated p32, protein arginine methyltransferases, and tubulins alpha 3 and beta 1 that is independent of its association with preribosomal ribonucleoprotein complexes.
Yanagida M, Hayano T, Yamauchi Y, Shinkawa T, Natsume T, Isobe T, Takahashi N