自噬-溶酶体途径调控核仁小核糖核蛋白 RRP9 的蛋白质降解

目的 研究核仁小核糖核蛋白 RRP9 的蛋白降解机制。 方法 组织表达谱分析 RRP9 在小鼠和人 类正常组织中的种属特异性和在不同组织中的特异性表达, 并分析 RRP9 在人的正常结直肠组织和结直肠 癌组织中的表达差异; 使用放线菌酮 (cycloheximide, CHX) 抑制结直肠癌细胞蛋白合成来检测 RRP9 蛋白 半衰期; 抑制自噬-溶酶体途径后检测 RRP9 蛋白含量变化以明确自噬-溶酶体途径对 RRP9 蛋白水平的影 响; 最后通过免疫荧光和免疫共沉淀检测 LC3b 与 RRP9 之间的相互作用。 结果 RRP9 为长寿命蛋白; 抑 制自噬-溶酶体途径使 RRP9 蛋白水平升高; RRP9 与 LC3b 之间存在相互作用。 结论 自噬-溶酶体途径调 控 RRP9 蛋白的降解。

Autophagy-lysosomal Pathway Regulates the Protein Degradation of the Small Nucleolar Ribonucleoprotein RRP9

Objective To study the protein degradation mechanism of the small nucleolar ribo-nucleoprotein RRP9.Methods Tissue expression profiling was used to analyze the species-specific and tissue-specific expression of RRP9 in normal tissues of mice and humans,and the differential expression of RRP9 in normal colorectal tissues and colorectal cancer tissues.Cycloheximide(CHX),a protein synthesis inhibitor,was used to detect the half-life of RRP9 in colorectal cancer cells.After inhibiting the autophagy-lysosome pathway,the expression of RRP9 was detected to un-derstand the effect of autophagy-lysosomal pathway on RRP9.Finally,immunofluorescence and co-immunoprecipitation were used to detect the interaction between LC3b and RRP9.Results RRP9 is a long-lived protein.Inhibition of autophagy-lysosomal pathway increased the level of RRP9.There was an interaction between RRP9 protein and LC3b in colorectal cancer cells.Conclusion The au-tophagy-lysosomal pathway regulates the degradation of RRP9 protein.