FMRP, PS1 And PS2 Interacting Proteins

Learning and memory are important necessarily functions of human brain. Our study focus on studying interacting proteins of FMRP (Fragile X mental retardation protein) and PS1 & PS2 (which linked with familial Alzheimer's disease), both of which can cause mental retardation in neural system, further elucidating their functions and possible signal pathways, then providing some clues for mechanism of the diseases.1. Study of the interaction between FMRP and NM23 H2Fragile X syndrome is the most common inherided form of human mental retardation, its disease gene FMR1 codes FMRP protein. By now ten interacting proteins of FMRP have been found. It shows that FMRP involves in transporting specific mRNAs and regulating its translation, also it can modulate dendrite postsynaptic proteins synthesis and dendrite spines maturation. By screening human fetal hippocampus cDNA library, We further try to find interacting protein of FMRP and study its function and possible cell process it involves in.Using FMRP isoform 1.1 with mutant NES inside exon 14 to screen cDNA library. We obtained a positive colony and the result showed it was NDK/NM23 H2. We confirmed their interaction using bi-directional yeast two-hybrid system. By constructing ten FMRP isoforms and using bi-directional yeast two-hybrid assay, we found the interaction site between NM23 H2 and FMRP located at FMRP exon 1-11, having no relation with FMRP exon 12-17; FMRP exon 1-6 and 2-7 couldn't interact with NM23 H2 solely. To further verify their interaction, we used cell co-immunoprecipitation technique. The result showed in vivo that FMRP could co-immunoprecipitate with NM23 H2, and NM23 could co-immunoprecipitate with FMRP too. So we verified that FMRP can interact directly with NM23 H2 and this interaction is specific. Now we are using cell immunofluorescence and co-focusing experiment to observe their co-location inside the cell and to find their related signal pathways.NM23 H2 is a tumor metastasis suppressor, activates trascription of c-myc and involves in cell growth and differentiation. It catalyses and synthesizes NTPs which are the substrate of DNA/RNA synthesis. Recently it shows NM23 can interact with Rad and involves in Ras signal pathway. FMRP might involve in Ras-related signal pathways by...