Hamburg Advanced Research Centre for Bioorganic Chemistry (HARBOR) & Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
The Calcium Signaling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Protein Sci. 2022 Jun;31(6):e4320. doi: 10.1002/pro.4320.
Transient receptor potential melastatin 2 (TRPM2) is a Ca -permeable, nonselective cation channel involved in diverse physiological processes such as immune response, apoptosis, and body temperature sensing. TRPM2 is activated by ADP-ribose (ADPR) and 2'-deoxy-ADPR in a Ca -dependent manner. While two distinct binding sites exist for ADPR that exert different functions dependent on the species, the involvement of either binding site regarding the superagonistic effect of 2'-deoxy-ADPR is not clear yet. Here, we report the crystal structure of the MHR1/2 domain of TRPM2 from zebrafish (Danio rerio), and show that both ligands bind to this domain and activate the channel. We identified a so far unrecognized Zn -binding domain that was not resolved in previous cryo-EM structures and that is conserved in most TRPM channels. In combination with patch clamp experiments we comprehensively characterize the effect of the Zn -binding domain on TRPM2 activation. Our results provide insight into a conserved motif essential for structural integrity and channel activity.
瞬时受体电位 melastatin 2（TRPM2）是一种 Ca2+通透、非选择性阳离子通道，参与多种生理过程，如免疫反应、细胞凋亡和体温感应。TRPM2 可被 ADP-核糖（ADPR）和 2'-脱氧-ADPR 以 Ca2+依赖性方式激活。虽然 ADPR 有两个不同的结合位点，但它们在不同物种中发挥不同的功能，而 2'-脱氧-ADPR 的超激动效应涉及到哪个结合位点尚不清楚。在这里，我们报告了来自斑马鱼（Danio rerio）的 TRPM2 的 MHR1/2 结构域的晶体结构，并表明这两种配体都结合到该结构域并激活通道。我们鉴定了一个迄今为止未被识别的 Zn 结合域，该结构域在以前的冷冻电镜结构中没有解析，并且在大多数 TRPM 通道中保守。结合膜片钳实验，我们全面表征了 Zn 结合域对 TRPM2 激活的影响。我们的结果提供了对结构完整性和通道活性至关重要的保守基序的深入了解。
