Rim是囊泡分泌活性区中的重要组成蛋白,它与细胞分泌和突触可塑性相关.在秀丽隐感线虫中只存在一种编码Rim的基因即unc-10.我们的研究发现,在线虫中Rim的基因突变unc-10(md1117)会导致致密核心囊泡的分泌缺陷.在活体中,unc-10突变虫系的神经多肽分泌显著下降.此外,在主要分泌致密核心囊泡的ALA神经元内,钙光解释放促发的快相分泌也比野生型减少.运用全内反射荧光显微成像技术,我们观察在unc-10缺失的情况下ALA神经元中致密核心囊泡的锚定过程,结果显示在细胞膜附近停留的囊泡数目减少,表明囊泡锚定受到阻碍.上述试验结果表明,UNC-10能够影响致密核心囊泡的分泌过程,其机制可能是影响了囊泡的锚定过程.
Rim is an active zone protein which is suggested to be involved in the regulation of vesicle exocytosis and synaptic plasticity. The C. elegans genome encodes only one Rim gene, unc-10. In this study, we demonstrate that UNC-10 is involved in the dense core vesicle (DCV) exocytosis in C. elegans neurons. We find that unc-10 mutants exhibit reduced peptide release in vivo. In IDA-1 ::GFP labelled ALA neurons, which serve as a good model for studying DCV exocytosis, mutations of UNC-10 lead to a visible reduction of the readily released pool (RRP) size. The analysis of vesicular docking by total internal reflection fluorescence microscopy (TIRFM) reveals that the loss of function of unc-10 hinders the docking of DCVs in neurons. The above results provide evidence that UNC-10 is required for the exocytosis of DCVs and may be involved in the docking step of DCV release.