Involved in an inositol phospholipid-based intracellular signaling cascade. Shows no PLC activity to phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol. Component in the phospho-dependent endocytosis process of GABA A receptor. Acts as an inhibitor of PPP1C. Interacts with PPP2CA, GABA receptor beta subunits, GABA receptor gamma-2 subunits (By similarity). Interacts with Ins(1,4,5)P3, Ins(1,4,5,6)P4, GABARAP, and PPP1C. May form a ternary complex with GABA receptor beta subunit and GABARAP. The formation of a ternary complex with GABA receptor beta subunit and GABARAP could be the key step for facilitating the association of GABARAP with the GABA receptor gamma-2 subunit and to allow it to be transported at the right destination. Expressed in brain. Found in the granular cell and Purkinje cell layers in the cerebellum; and in the hippocampal pyramidal cells, dentate granule cells and pyramidal granule cells of the cerebral cortex in the cerebrum. Phosphorylation of Thr-94 resulted in dissociation of PPP1C from PRIP1 (By similarity). In vitro, phosphorylated by the catalytic subunit of PKA. Belongs to the PRIP family. In the PI-PLC X-box Asn-459 is present instead of the conserved His which is one of the active site residues. It is therefore expected that this protein lacks catalytic activity.