Structural basis for the synergistic assembly of the snRNA export complex.

ABSTRACT: The nuclear cap-binding complex (CBC) and its partner Arsenite-Resistance Protein 2 (ARS2) regulate the fate of RNA polymerase II transcripts via mutually exclusive interactions with RNA effectors. One such effector is PHAX, which mediates the nuclear export of U-rich small nuclear RNAs (snRNAs). Here we present the cryo-electron microscopy structure of the human snRNA export complex comprising phosphorylated PHAX, CBC, CRM1-RanGTP and capped RNA. The central region of PHAX bridges CBC to the export factor CRM1-RanGTP, while also reinforcing cap dinucleotide binding. Additionally, PHAX interacts with a distant region of CRM1, facilitating contacts of the essential phosphorylated region of PHAX with the prominent basic surface of RanGTP. CBC engagement within the snRNA export complex is inc

SUBMITTER: Dubiez E 

PROVIDER: S-EPMC12350170 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature