Localization of a novel inositol 1,4,5-trisphosphate binding protein, p130 in rat brain.

We have isolated a novel inositol 1,4,5-trisphosphate binding protein with molecular mass of 130 kDa (p130), homologous to phospholipase C-delta1 in amino acid sequence but with no catalytic activity. Here we report the expression and localization of p130 at the mRNA level in rat brain. Northern blotting showed that gene expression encoding p130 was most abundant in brain. Brain localization of p130-mRNA using an in situ hybridization technique revealed that in the cerebellum, the mRNA was detected in the granular cell and Purkinje cell layers, and cerebellar nuclei. In the cerebrum, the mRNA was localized in hippocampal pyramidal cells, dentate granule cells and pyramidal and/or granule cells of the cerebral cortex. The brain localization of p130-mRNA was similar to that of the beta-subtype of phospholipase C, indicating that p130 may be mainly involved in phospholipase Cbeta-mediated signaling.