Pal Kuntal, Bandyopadhyay Abhishek, Zhou X Edward, Xu Qingping, Marciano David P, Brunzelle Joseph S, Yerrum Smitha, Griffin Patrick R, Vande Woude George, Melcher Karsten, Xu H Eric
Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, MI 49503, USA.
GMCA at Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA.
Structure. 2017 Jun 6;25(6):867-877.e3. doi: 10.1016/j.str.2017.04.015. Epub 2017 May 18.
The nuclear pore complex subunit TPR is found in at least five different oncogenic fusion kinases, including TPR-MET, yet how TPR fusions promote activation of kinases and their oncogenic activities remains poorly understood. Here we report the crystal structure of TPR(2-142), the MET fusion partner of oncogenic TPR-MET. TPR(2-142) contains a continuous 124-residue α helix that forms an antiparallel tetramer from two leucine zipper-containing parallel coiled coils. Remarkably, single mutations cause strikingly different conformations of the coiled coil, indicating its highly dynamic nature. We further show that fusion of TPR(2-142) to the MET intracellular domain strongly and selectively stabilizes the αG helix of the MET kinase domain, and mutations of only the TPR leucine zipper residues at the junction to MET, but not other leucine zipper residues, abolish kinase activation. Together, these results provide critical insight into the TPR structure and its ability to induce dimerization and activation of fusion kinases.
核孔复合体亚基TPR存在于至少五种不同的致癌融合激酶中，包括TPR-MET，但TPR融合如何促进激酶激活及其致癌活性仍知之甚少。在这里，我们报道了致癌性TPR-MET的MET融合伴侣TPR(2-142)的晶体结构。TPR(2-142)包含一个连续的124个残基的α螺旋，该螺旋由两个含亮氨酸拉链的平行卷曲螺旋形成一个反平行四聚体。值得注意的是，单个突变会导致卷曲螺旋的构象显著不同，表明其具有高度动态性。我们进一步表明，TPR(2-142)与MET细胞内结构域的融合强烈且选择性地稳定了MET激酶结构域的αG螺旋，并且仅在与MET连接处的TPR亮氨酸拉链残基发生突变，而不是其他亮氨酸拉链残基，会消除激酶激活。总之，这些结果为TPR结构及其诱导融合激酶二聚化和激活的能力提供了关键见解。
