Inter-action of protein phosphatase type 1 with a splicing factor

A gizzard cDNA Library was screened by the two-hybrid system using as bait the delta isoform of the catalytic subunit of protein phosphatase 1 (PP1 delta). Among the proteins identified was a fragment of the polypyrimidine tract-binding protein-associated splicing factor (PSF) and for 242 residues was 97.1% identical to the human isoforms. Binding of PSF and PP1 delta was confirmed by inhibition of phosphatase activity and by an overlay technique. The PP1 delta binding site was contained in the N-terminal 82 residues of the PSF fragment. PSF may therefore act as a PP1 target molecule in the spliceosome.