Chini B, Clementi F, Hukovic N, Sher E
Department of Medical Pharmacology, University of Milan, Italy.
Proc Natl Acad Sci U S A. 1992 Mar 1;89(5):1572-6. doi: 10.1073/pnas.89.5.1572.
alpha-Bungarotoxin (alpha Bgtx) is a toxin known to interact with muscle nicotinic receptors and with some neuronal nicotinic receptors. We show that alpha Bgtx binding sites are also expressed in nonmuscle and nonneuronal human cells, including small cell lung carcinoma and several epithelial cell lines. These receptors are immunologically related to the alpha Bgtx receptors of unknown function described in the nervous system and in the IMR32 neuroblastoma cell line and are distinct from muscle nicotinic receptors. We have also cloned from IMR32 cells the human alpha 5-nicotinic receptor subunit, which is supposed to participate in the formation of alpha Bgtx receptors. Transcripts corresponding to the alpha 5-subunit gene were found not only in neuroblastoma cells but also in all the cell lines expressing alpha Bgtx receptors, with the exception of the TE671 cell line, whose nicotinic receptor subunits are of the muscle type. We conclude that both alpha Bgtx receptors and the alpha 5-nicotinic subunit gene are not neuron-specific, as previously thought, but are expressed in a number of human cell lines of various origin.
α-银环蛇毒素（αBgtx）是一种已知可与肌肉烟碱型受体及某些神经元烟碱型受体相互作用的毒素。我们发现αBgtx结合位点也在非肌肉和非神经元的人类细胞中表达，包括小细胞肺癌细胞和几种上皮细胞系。这些受体在免疫学上与神经系统及IMR32神经母细胞瘤细胞系中描述的功能未知的αBgtx受体相关，且与肌肉烟碱型受体不同。我们还从IMR32细胞中克隆出了人类α5-烟碱型受体亚基，该亚基被认为参与αBgtx受体的形成。不仅在神经母细胞瘤细胞中，而且在所有表达αBgtx受体的细胞系中都发现了与α5-亚基基因对应的转录本，但TE671细胞系除外，其烟碱型受体亚基属于肌肉型。我们得出结论，αBgtx受体和α5-烟碱型亚基基因并非如先前认为的那样具有神经元特异性，而是在多种来源的许多人类细胞系中表达。
