Structure-function analysis of PMCA-Neuroplastin/Basigin complexes, the native Ca2+ pump(s) of the plasma membrane

PMCA-Neuroplastin/Basigin 复合物（质膜的天然 Ca2 泵）的结构功能分析

• 批准号: 446245862
• 负责人: Professor Dr. Bernd Fakler
• 金额: --
• 依托单位: Lehrstuhl für Physiologie II - Molecular Physiology
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/446245862?language=en
• 关键词: Structure; function; analysis; PMCA; Neuroplastin

Calcium (Ca2+) signaling controls a broad variety of cellular processes and reaction pathways ranging from transmitter release and contraction to regulation of enzymatic activities and/or cell motility: These processes are switched on by influx of Ca2+ into the cytosol, and they are switched off by the concerted action of various Ca2+ transporters, most importantly Ca2+-ATPases (or pumps) that are located in the sarco/endoplasmic reticulum (SERCA) or the plasma membrane (PMCA). We have recently identified PMCAs in any type of cell as bimolecular complexes assembled from two ATPase subunits (PMCAs1-4) and two single-span membrane proteins neuroplastin or basigin. Co-assembly of the latter with the PMCA proteins is obligatory for both stabilization and trafficking of the complexes, as well as for their substrate transport. In fact, binding of neuroplastin or basigin increases the rates of Ca2+-transport by more than two orders of magnitude, thus promoting Ca2+-clearing within 10s of milliseconds rather than seconds, as previously assumed. The structural and functional basis of this profoundly increased transport activity, as well as the role of the two auxiliary subunits for the cell-physiology of native PMCAs are currently unknown. This proposal aims at a comprehensive understanding of the structural and functional basis for the formation and operation of PMCA-neuroplastin/basigin complexes. For this purpose we will pursue the following closely interrelated aims and experimental approaches/steps: (1) Elucidate 3D-structures of PMCA2-neuroplastin and PMCA4-basigin complexes, and of PMCA2 in auxiliary subunit-free ‘apo’ state by cryo-EM, (2) Perform structure-function analyses of the Ca2+-transport in PMCA-neuroplastin/basigin complexes, (3) Unravel the interactome of native PMCAs with emphasis on interactions via the Ig-domains of neuroplastin and basigin.

钙（Ca2+）信号传导控制了各种细胞过程和反应途径，从释放和/或细胞运动范围从发射器释放和收缩。 Ca2+转运蛋白，最重要的是局部（SERCA）或质膜（PMCA）的Ca2+ -Atpass（或泵）。单跨膜神经塑料或basigin蛋白质的稳定和运输是强制性的，就像其底物运输一样因此，正如先前假定的那样，促进Ca2+hin 10s的毫秒而不是秒为此目的，对PMCA-神经素/Basigin compplexess的形成和运行的结构和功能基础的全面理解我们将紧密相互关联的目的和实验方法：（1）阐明欧洲类蛋白和PMCA4-BASIGIN复合物的3D结构，以及Cryo-em的无辅助亚基'状态的PMCA2，（2）在PMCA-NEUROPLASTIN/BASIGIN复合体中执行Ca2+ - 传输的结构功能，（3）PM CAS，强调通过Neuroplastin of Neuroplastin of Ig-domomain的相互作用和Basigin。