SSU72 RNA Polymerase II CTD Phosphatase Homolog (SSU72)

Ssu72, a component of the yeast cleavage/polyadenylation factor (CPF) complex, is a CTD phosphatase with specificity for S5-P. Ssu72 Is an RNA polymerase II CTD phosphatase.

Ssu72 catalyzes CTD S5-P dephosphorylation in association with the Pta1 component of the CPF complex, although its essential role in 3' end processing is independent of catalytic activity. Depletion of Ssu72 impairs transcription in vitro, and this defect can be rescued by recombinant, catalytically active Ssu72. Ssu72 has a dual role in transcription, one as a CTD S5-P phosphatase that regenerates the initiation-competent, hypophosphorylated form of RNAP II and the other as a factor necessary for cleavage of pre-mRNA and efficient transcription termination.