Interaction of protein phosphatase type 1 with a splicing factor

Area of Science:

• Molecular Biology
• RNA Splicing
• Protein Interactions

Background:

• Protein phosphatase 1 (PP1) is a crucial enzyme involved in various cellular processes.
• The delta isoform of PP1 (PP1delta) has specific cellular roles, including potential involvement in RNA processing.
• The polypyrimidine tract-binding protein-associated splicing factor (PSF) is known to participate in RNA splicing.

Purpose of the Study:

• To identify proteins that interact with the delta isoform of protein phosphatase 1 (PP1delta).
• To investigate the potential role of identified interacting proteins in cellular functions, specifically RNA splicing.

Main Methods:

• Screening of a gizzard cDNA library using a yeast two-hybrid system with PP1delta as bait.
• Confirmation of protein-protein interactions using phosphatase activity inhibition assays.
• Employing an overlay technique to validate binding between PP1delta and the identified splicing factor.

Main Results:

• A fragment of the polypyrimidine tract-binding protein-associated splicing factor (PSF) was identified as interacting with PP1delta.
• The identified PSF fragment showed high sequence identity (97.1%) to human isoforms.
• The binding site for PP1delta was localized to the N-terminal 82 residues of the PSF fragment.

Conclusions:

• PSF directly binds to PP1delta, suggesting a functional interaction.
• The spliceosome is a potential cellular location for this interaction.
• PSF may function as a target molecule for PP1delta within the spliceosome, influencing RNA splicing regulation.