Interaction between the photoreceptor-specific tubby-like protein 1 and the neuronal-specific GTPase Dynamin-1
Interaction between the photoreceptor-specific tubby-like protein 1 and the neuronal-specific GTPase Dynamin-1
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DOI：
10.1167/iovs.06-0059
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发表时间：
2007-06-01
影响因子：
4.4
通讯作者：
Hagstrom, Stephanie A.
中科院分区：
文献类型：
--
作者：
Xi, Quansheng;Pauer, Gayle J. T.;Hagstrom, Stephanie A.
目的。Tubby-like Proteins(TULP)是一个由四种蛋白质组成的家族，其中两种与神经感觉性疾病表型有关。TULP1是一种光感受器特异性蛋白，在视网膜色素变性中发生突变，视网膜色素变性是一种遗传性视网膜疾病，其特征是视杆细胞和视锥细胞退化。为了研究TULP1在维持光感受器健康中的作用，作者寻求相互作用蛋白的鉴定方法。方法从视网膜裂解物中免疫沉淀，然后用液相色谱-串联质谱仪和体外结合分析来鉴定TULP1的结合伙伴。对野生型小鼠视网膜的总RNA进行RT-PCR，以确定Dynamin-1亚型在视网膜中的表达。免疫细胞化学方法检测TULP1和Dynamin-1在光感受器细胞中的定位。结果视网膜裂解液免疫沉淀鉴定Dynamin-1为可能的TULP1结合伙伴。GST下拉分析进一步支持TULP1和Dynamin-1之间的相互作用。在光感受器细胞中，Dynamin-1和TULP1主要共定位于外丛状层，在那里光感受器终末与二级神经元突触，并在较小程度上与发生极化蛋白转位的内节突触。对幼龄Tulp1(-/-)小鼠的ERG分析表明，当视网膜保留完整的光感受器细胞时，b波降低。结论这些数据表明TULP1与Dynamin-1相互作用，提示TULP1参与了光感受器蛋白的囊泡运输，无论是在突触传递的神经末梢，还是在蛋白质移位到外段的内段。这些结果也提出了正常的突触功能需要TULP1的可能性，它们促使人们更仔细地观察发育中的W401(-/-)视网膜的突触结构。
PURPOSE. Tubby-like proteins (TULPs) are a family of four proteins, two of which have been linked to neurosensory disease phenotypes. TULP1 is a photoreceptor-specific protein that is mutated in retinitis pigmentosa, an inherited retinal disease characterized by the degeneration of rod and cone photoreceptor cells. To investigate the function of TULP1 in maintaining the health of photoreceptors, the authors sought the identification of interacting proteins.METHODS. Immunoprecipitation from retinal lysates, followed by liquid chromatography tandem mass spectrometry and in vitro binding assays, were used to identify TULP1 binding partners. RT-PCR was performed on total RNA from wild-type mouse retina to identify the Dynamin-1 isoform expressed in the retina. Immunocytochemistry was used to determine the localization of TULP1 and Dynamin-1 in photoreceptor cells. Electroretinography (ERG) and light microscopy were used to phenotype tulp1(-/-) mice at a young age.RESULTS. Immunoprecipitation from retinal lysate identified Dynamin-1 as a possible TULP1 binding partner. GST pull-down assays further supported an interaction between TULP1 and Dynamin-1. In photoreceptor cells, Dynamin-1 and TULP1 colocalized primarily to the outer plexiform layer, where photoreceptor terminals synapse on second-order neurons and, to a lesser extent, to the inner segments, where polarized protein translocation occurs. ERG analyses in young tulp1(-/-) mice indicated a decreased b-wave at ages when the retina retained a full complement of photoreceptor cells.CONCLUSIONS. These data indicated that TULP1 interacts with Dynamin-1 and suggested that TULP1 is involved in the vesicular trafficking of photoreceptor proteins, both at the nerve terminal during synaptic transmission and at the inner segment during protein translocation to the outer segment. These results also raised the possibility that normal synaptic function requires TULP1, and they motivate a closer look at synaptic architecture in the developing W401(-/-) retina.