The pathogenesis of autoimmune illnesses involves activation and proliferation of effector memory T cells (TEM cells) [5]. Through the activation of TEM cells, the expression from the Kv1.three channel was up-regulated drastically, from about 300 molecules to about 15002000 molecules per cell [6]. Selective blockage of Kv1.3 channels was experimentally demonstrated to suppress TEM cell proliferation [7]. There is also a developing body of evidence suggesting that Kv1.three channel blockers have valuable therapeutic effect on rheumatoid arthritis [8], autoimmune encephalitis [9] as well as other autoimmune diseases [10]. With the establishment of Kv1.three channel as a fantastic drug target for autoimmune diseases, substantial efforts have already been produced to develop selective and efficientThe Author(s) 2017. This article is distributed below the terms in the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, supplied you give proper credit for the original author(s) along with the supply, deliver a hyperlink to the Creative Commons license, and indicate if modifications have been created. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies towards the data created available within this report, unless otherwise stated.Zou et al. Cell Biosci (2017) 7:Page 2 ofKv1.3 channel blockers and present lead drugs for the therapy of autoimmune illnesses. Toxin peptides from all-natural venomous animals comprise the biggest families of ion channel blockers, and they are becoming increasingly useful sources of new drugs for channelopathies. Scorpion is amongst the oldest species which have existed on earth for more than 400 million years. A sizable quantity of research have showed that scorpion venom consists of lots of brief peptides with 20-80 amino acid residues, which is a vital Methylene blue MedChemExpress supply of kv1.three channel inhibitors [11]. For scorpion species which is usually farmed on a big scale, for example Buthus martensii Karsch, higher abundance active polypeptides can be straight separated and extracted from scorpion venom. On the other hand, for low abundance scorpion toxin polypeptide or for scorpion species which cannot be cultured in big scale, it can be difficult to extract the active polypeptide directly from scorpion venom. Considering that transcriptomic method has been proved to become one of many most effective tactics for screening functional genes in the venom glands of scorpions [12, 13], the mixture of contemporary transcriptome sequencing and genetic engineering procedures can proficiently overcome this difficulty. In this study, we screened a scorpion toxin KTX-Sp4 gene by transcriptome sequencing in the venom glands of Scorpiops pococki from Xizang province. The peptides coded by KTX-Sp4 gene have a high homology with Kv1.3 channel inhibitors HLKTx4 [14], J123 [15], pMeKTx22-1 and LmKTx8 [16]. Entire cell patch-clamp experiments indicated that peptide KTX-Sp4 had potentially selective blocking effect on Kv1.three over Kv1.1 channel, and also the selective recognition of KTX-Sp4 on Kv1.3 more than Kv1.1 was determined by four different amino acid residues within the turret area between Kv1.1 and Kv1.3 channels.(Nr), Swiss-prot Apricitabine web protein (Swiss-Prot), Kyoto Encyclopedia of Gene and Genomes (KEGG), Cluster of Orthologous Group of proteins (COG) and Non-redundant nucleotide database (Nt). For prediction of unigene functions, we employed Blast2GO program to annotate unigenes and o.