Immunohistochemical Study on the Localization of Amphiphysin Ir, Novel Retina-Specific Variants of Amphiphysin I, in the Rat Retina

点击翻译按钮获取中文摘要

Amphiphysin I (amph I) is an SH3 domain-containing protein that has been implicated in synaptic vesicle recycling through clathrin-mediated endocytosis. We have recently cloned novel splice variants of amph I, amph Ir, that are specifically expressed in retina. To provide insight into the function of amph Ir, we examined its precise localization by immunocytochemistry at light and electron microscopic levels. We found that amph Ir is specifically localized at ribbon synapses of photoreceptor and bipolar cells. In addition, immunoprecipitation experiments revealed that amph Ir is bound to the amph I isoform, amph II, an endocytic protein, clathrin, and a cytoskeletal protein, actin. The colocalization of amph Ir and these proteins in retinal sections was confirmed by double-labeling immunofluorescence. These findings suggest that amph Ir plays distinctive roles in retinal ribbon synapses via the interaction with amph II, clathrin, and actin.