Tsyba Liudmyla, Gryaznova Tetyana, Dergai Oleksandr, Dergai Mykola, Skrypkina Inessa, Kropyvko Sergiy, Boldyryev Oleksiy, Nikolaienko Oleksii, Novokhatska Olga, Rynditch Alla
Institute of Molecular Biology and Genetics, 150 Zabolotnogo Street, Kyiv 03143, Ukraine.
Biochem Biophys Res Commun. 2008 Aug 8;372(4):929-34. doi: 10.1016/j.bbrc.2008.05.156. Epub 2008 Jun 6.
Intersectin 1 (ITSN1) is a conserved adaptor protein implicated in endocytosis, regulation of actin cytoskeleton rearrangements and mitogenic signaling. Its expression is characterized by multiple alternative splicing. Here we show neuron-specific expression of ITSN1 isoforms containing exon 20, which encodes five amino acid residues in the first SH3 domain (SH3A). In vitro binding experiments demonstrated that inclusion of exon 20 changes the binding properties of the SH3A domain. Endocytic proteins dynamin 1 and synaptojanin 1 as well as GTPase-activating protein CdGAP bound the neuron-specific variant of the SH3A domain with higher affinity than ubiquitously expressed SH3A. In contrast, SOS1, a guanine nucleotide exchange factor for Ras, and the ubiquitin ligase Cbl mainly interact with the ubiquitously expressed isoform. These results demonstrate that alternative splicing leads to the formation of two pools of ITSN1 with potentially different properties in neurons, affecting ITSN1 function as adaptor protein.
相交蛋白1（ITSN1）是一种保守的衔接蛋白，参与内吞作用、肌动蛋白细胞骨架重排的调节以及有丝分裂信号传导。其表达具有多种可变剪接特征。在此我们展示了包含外显子20的ITSN1亚型在神经元中的特异性表达，该外显子在第一个Src同源3结构域（SH3A）中编码五个氨基酸残基。体外结合实验表明，外显子20的包含改变了SH3A结构域的结合特性。内吞蛋白发动蛋白1和突触素1以及GTP酶激活蛋白CdGAP与SH3A结构域的神经元特异性变体结合的亲和力高于普遍表达的SH3A。相比之下，Ras的鸟嘌呤核苷酸交换因子SOS1和泛素连接酶Cbl主要与普遍表达的异构体相互作用。这些结果表明，可变剪接导致在神经元中形成具有潜在不同特性的两群ITSN1，影响ITSN1作为衔接蛋白的功能。
