| Modification Notes |
NPA1 (nucleolar pre-ribosomal-associated protein 1), also known as URB1, is a 2271 amino acid protein that is homologous to the S. cerevisiae protein URB1. The S. cerevisiae URB1 is a nucleolar protein involved in the normal accumulation of 25S and 5.8S rRNAs and may also play a role in the biosynthesis of the 60S ribosomal unit. Also localized to the nucleolus, NPA1 is thought to have the same functions as S. cerevisea URB1. NPA1 is expressed at highest levels in kidney, heart, brain, lung, spleen, testis, pancreas, skeletal muscle, ovary, and prostate, with lowest levels in small intestine and thymus. |