Murata Yasunobu, Doi Tomoko, Taniguchi Hisaaki, Fujiyoshi Yoshinori
Department of Biophysics, Graduate School of Science, Kyoto University, Oiwake, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.
Biochem Biophys Res Commun. 2005 Feb 4;327(1):183-91. doi: 10.1016/j.bbrc.2004.11.154.
Proteomic analyses have revealed a novel synaptic proline-rich membrane protein: PRR7 (proline rich 7), in the postsynaptic density (PSD) fraction of rat forebrain. PRR7 is 269 amino acid residues long, and displays a unique architecture, composed of a very short N-terminal extracellular region, a single membrane spanning domain, and a cytoplasmic domain possessing a proline-rich sequence and a C-terminal type-1 PDZ binding motif. A fraction of PRR7 accumulates in spines along with synapse maturation, and colocalizes with PSD-95 in a punctate pattern in rat hippocampal neural cultures. Immunoprecipitation and GST pull-down assays demonstrated that PRR7 binds to the third PDZ domain of PSD-95. In addition, the NMDA receptor subunits, NR1 and NR2B, specifically co-immunoprecipitated with PRR7. These results suggest that PRR7 is involved in modulating neural activities via interactions with the NMDA receptor and PSD-95, and PSD core formation.
PRR7（富含脯氨酸7），存在于大鼠前脑的突触后致密物（PSD）组分中。PRR7由269个氨基酸残基组成，具有独特的结构，由一个非常短的N端细胞外区域、一个单跨膜结构域和一个具有富含脯氨酸序列的胞质结构域以及一个C端1型PDZ结合基序组成。随着突触成熟，一部分PRR7在棘突中积累，并在大鼠海马神经培养物中与PSD-95以点状模式共定位。免疫沉淀和GST下拉实验表明PRR7与PSD-95的第三个PDZ结构域结合。此外，NMDA受体亚基NR1和NR2B与PRR7特异性共免疫沉淀。这些结果表明PRR7通过与NMDA受体和PSD-95相互作用以及PSD核心形成参与调节神经活动。
