Involved in branched RNA metabolism, modulating the turnover of lariat-intron pre-mRNAs by the lariat-debranching enzyme DBR1. Enhances the debranching activity of DBR1 in vitro. Interacts with DBR1. Interacts with SYF1, a component of the NTC complex. Interacts with lariat-introns and lariat-intermediates. Relocalizes to the cytoplasm in response to hypoxia. Accumulates pre-mRNA splicing intermediates. Present with 1270 molecules/cell in log phase SD medium. Belongs to the CWF19 family.