RNA-binding protein involved in deadenylation-dependent decapping of mRNAs, leading to the degradation of mRNAs. Acts as a scaffold protein that connects deadenylation and decapping machinery. Required for cytoplasmic mRNA processing body (P-body) assembly. Interacts (via region A) with DDX6/RCK. Interacts (via region H and region C) with LSM1 and LSM4. Interacts (via region N) with DCP1A, DCP2, EDC3, EDC4 and XRN1. Interacts with the CCR4-NOT complex. Interacts with the Lsm-containing SMN-Sm protein complex. Interacts with EIF4ENIF1/4E-T. Predominantly cytoplasmic. Shuttles between the nucleus and the cytoplasm in a CRM1-dependent manner. Enriched in splicing speckles. Localization to nuclear foci and speckles requires active transcription. Excluded from the nucleolus. The region C, also named Pat-C, is required for RNA-binding and mediates the binding with the Lsm-containing SMN-Sm protein complex and the decapping machinery. It folds into an alpha-alpha superhelix, exposing conserved and basic residues on one side of the domain. Belongs to the PAT1 family.