The HNF-1α-SNARE connection

Maturity-onset diabetes of the young (MODY) is a monogenic form of type 2 diabetes mellitus that is characterized by impairment of glucose-stimulated insulin secretion from pancreatic β-cells. We previously reported that heterozygous mutations of the hepatocyte nuclear factor (HNF)-1α gene cause a form of MODY (MODY3). We have subsequently found that collectrin, a recently cloned kidney-specific gene of unknown function, is a novel target of HNF-1α in pancreatic β-cells. In addition, we have demonstrated that collectrin forms a complex with the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex by direct interaction with snapin, a protein that is thought to be involved in neurotransmission by binding to synaptosomal-associated protein, 25 KD (SNAP25). Collectrin favours the formation of SNARE complexes and controls insulin exocytosis.     

TrkA与snapin蛋白的直接相互作用

目的确认TrkA与snapin蛋白间的直接相互作用。方法采用DNA重组技术,构建增强型荧光蛋白表达载体pECFP-TrkAICD(TrkA膜内区)和pEYFP-snapin,共转染HEK 293T细胞后以激光扫描共聚焦显微镜观察并进行荧光共振能量转移(fluorescence resonance energy transfer,FRET)分析。结果成功构建了snapin和TrkA的重组质粒,共转染细胞后激光扫描共聚焦显微镜分析表明两种蛋白分布在细胞质同一层面,荧光共振能量转移(FRET)分析表明能量转移效率>5%,与对照相比有显著区别(P<0.05)。结论激光扫描共聚焦及FRET实验结果都证明了TrkA膜内区与snapin两个蛋白之间存在着直接的相互作用。