Chen Yushu, Bharill Shashank, Isacoff Ehud Y, Chalfie Martin
Department of Biological Sciences, Columbia University, New York, NY 10027;
Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720.
Proc Natl Acad Sci U S A. 2015 Sep 15;112(37):11690-5. doi: 10.1073/pnas.1515968112. Epub 2015 Aug 31.
Caenorhabditis elegans senses gentle touch in the six touch receptor neurons (TRNs) using a mechanotransduction complex that contains the pore-forming degenerin/epithelial sodium channel (DEG/ENaC) proteins MEC-4 and MEC-10. Past work has suggested these proteins interact with the paraoxonase-like MEC-6 and the cholesterol-binding stomatin-like MEC-2 proteins. Using single molecule optical imaging in Xenopus oocytes, we found that MEC-4 forms homotrimers and MEC-4 and MEC-10 form 4:4:10 heterotrimers. MEC-6 and MEC-2 do not associate tightly with these trimers and do not influence trimer stoichiometry, indicating that they are not part of the core channel transduction complex. Consistent with the in vitro data, MEC-10, but not MEC-6, formed puncta in TRN neurites that colocalize with MEC-4 when MEC-4 is overexpressed in the TRNs.
秀丽隐杆线虫利用一种机械转导复合物在六个触觉感受神经元（TRN）中感知轻柔触摸，该复合物包含形成孔道的退化蛋白/上皮钠通道（DEG/ENaC）蛋白MEC-4和MEC-10。过去的研究表明，这些蛋白与对氧磷酶样蛋白MEC-6和胆固醇结合的气孔蛋白样蛋白MEC-2相互作用。利用非洲爪蟾卵母细胞中的单分子光学成像技术，我们发现MEC-4形成同源三聚体，MEC-4和MEC-10形成4:4:10异源三聚体。MEC-6和MEC-2并不与这些三聚体紧密结合，也不影响三聚体的化学计量比，这表明它们不是核心通道转导复合物的一部分。与体外数据一致，当MEC-4在TRN中过表达时，MEC-10而非MEC-6在TRN神经突中形成斑点，且与MEC-4共定位。
