A novel scaffold protein, TANC, possibly a rat homolog of Drosophila rolling pebbles (rols), forms a multiprotein complex with various postsynaptic density proteins

We cloned from the rat brain a novel gene, tanc (GenBank™ Accession No. AB098072), which encoded a protein containing three tetratricopeptide repeats (TPRs), ten ankyrin repeats and a coiled-coil region, and is possibly a rat homolog of Drosophila rolling pebbles (rols). The fane gene was expressed widely in the adult rat brain. Subcellular distribution, immunohistochemical study of the brain and immunocytochemical studies of cultured neuronal cells indicated the postsynaptic localization of TANC protein of 200 kDa. Pull-down experiments showed that TANC protein bound PSD-95, SAP97, and Homer via its C-terminal PDZ-binding motif, -ESNV, and fodrin via both its ankyrin repeats and the TPRs together with the coiled-coil domain. TANC also bound the αsubunit of Ca²⁺/calmodulin-dependent protein kinase II. An immunoprecipitation study showed TANC association with various postsynaptic proteins, including guanylate kinase-associated protein (GKAP), α-internexin, and N-methyl-D-aspartate (NMDA)-type glutamate receptor 2B and AMPA-type glutamate receptor (GluR1) subunits. These results suggest that TANC protein may work as a postsynaptic scaffold component by forming a multiprotein complex with various postsynaptic density proteins.