Characterization of physiological and pathophysiological N-Ank proteins in membrane shaping and cellular morphogenesis

多细胞生物的细胞需要采用特定的形态。多细胞生物的大多数细胞在发育过程中经历复杂的形状调节。神经元在神经网络形成过程中表现出广泛的形态变化。然而，引起膜拓扑变化的分子机制还远未被理解，主要是因为对能促进局部膜曲率的膜形成蛋白的了解仍然有限。我们最近的分析揭示了一个以前未被识别的大蛋白质家族的几个成员，我们称之为N-Ank蛋白质，使用特定的分子特性来结合和塑造膜。与此一致的是，功能分析显示N-Ank蛋白在神经元早期形态发生中进一步发挥重要作用。本文提出的对迄今为止仅预测的与几种人类疾病和病理生理相关的N-Ank家族成员及其在生理和疾病中的细胞作用的分子机制特性的综合表征，有望在一方面证明N-Ank模块的普遍性，并进一步定义和解释N-Ank蛋白的不同细胞功能。我们计划研究以下关键机制的重要性和贡献：1)n端两亲性α-螺旋的膜插入；2)锚蛋白重复序列的弯曲阵列的曲率感应；3)在不同的N-Ank蛋白的野生型和疾病相关版本的膜结合和形成中，螺旋介导的自结合在质膜上形成纳米结构域。此外，我们将继续研究现有的工作假设，即不同膜拓扑识别和调节蛋白（即N-Ank和F-BAR蛋白家族成员）在形成膜和整个细胞中的物理和潜在的功能合作。在分析了这些膜形成器的合作、冗余和独特功能之后，我们将研究它们在神经形态发生中的功能合作。综上所述，我们在这里提出了生理和病理生理N-Ank蛋白的分子特征，这是一类新的强大的膜塑造器，从而赋予N-Ank蛋白超家族机制和细胞生物学功能。

Cells of multicellular organisms need to adopt specific morphologies. Most cells of multicellular organisms undergo sophisticated shape modulations during development. Neurons show extensive morphology changes during neuronal network formation. However, the molecular mechanisms bringing about membrane topology changes are far from understood – mainly because knowledge of membrane-shaping proteins that can promote local membrane curvatures is still limited. Our analyses recently unveiled that several members of a large, previously unrecognised protein family, which we termed N-Ank proteins, use specific molecular properties to bind and shape membranes. Consistently, functional analyses revealed that the N-Ank protein ankycorbin exemplarily characterized further plays an important role in early morphogenesis of neurons. The here proposed comprehensive characterization of the molecular mechanistic properties of so far only predicted members of the N-Ank family that have been associated with several human diseases and pathophysiologies and of their cellular role in physiology and disease is expected to prove the universality of the N-Ank module on one side and to furthermore define and explain distinct cellular functions of N-Ank proteins. We plan to investigate the importance and the contribution of the following crucial mechanisms i) membrane insertion by an N-terminal amphipathic α-helix, ii) curvature sensing by the curved array of ankyrin repeats and iii) coiled coil-mediated self-association to form nanodomains in the plasma membrane in membrane binding and shaping of wild-type and disease-associated version of distinct N-Ank proteins. Furthermore, we will pursue the exiting working hypothesis of a physical and potentially also functional cooperation of different membrane topology recognizing and modulating proteins, i.e. of N-Ank and F-BAR protein family members in shaping membranes and entire cells. Following analyses of putative cooperation, redundancy and distinct function of these membrane shapers we will investigate their putative functional cooperation in neuromorphogenesis.In summary, we here propose to molecularly characterize physiological and pathophysiological N-Ank proteins, a new class of powerful membrane shapers, and thereby assign mechanistic and cell biological functions to the N-Ank protein superfamily.