URB1 ribosome biogenesis factor (URB1)

URB1 ribosome biogenesis factor (URB1) is a nucleolar protein essential for ribosome biogenesis, functioning as a ribosome assembly factor required for the maturation of 5.8S and large subunit (LSU) rRNAs from the tricistronic rRNA transcript[1][4]. URB1 is localized in the nucleolus's fibrillar center and exhibits RNA binding activity[1]. URB1 is upregulated by mTORC1 signaling and acts as an oncogenic driver in colorectal cancer by promoting cell proliferation, migration, and cell cycle progression, integrating signals from pathways like mTORC1 and transcriptional regulators (such as ATF4 via XBP1)[1][2][4]. There are currently no known clinically used drugs that directly target URB1. However, its inhibition (e.g., by disrupting mTORC1/URB1 signaling) impairs tumor growth, pointing to its potential as a therapeutic target, particularly in oncology[1][2][4].

Other names

C21orf108KIAA0539NOP254NPA1Nucleolar pre-ribosomal-associated protein 1Nucleolar protein 254 kDaURB1 ribosome biogenesis 1 homolog