Department of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław, 50-383, Wrocław, Poland.
Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375, Wrocław, Poland.
Sci Rep. 2021 Jul 20;11(1):14751. doi: 10.1038/s41598-021-93982-3.
Flotillins are the major structural proteins in erythroid raft domains. We have shown previously that the dynamic nanoscale organization of raft domains in erythroid cells may depend on flotillin-MPP1 interactions. Here, by using molecular dynamic simulations and a surface plasmon resonance-based approach we determined that high-affinity complexes of MPP1 and flotillins are formed via a so far unidentified region within the D5 domain of MPP1. Significantly, this particular "flotillin binding motif" is of key physiological importance, as overexpression of peptides containing this motif inhibited endogenous MPP1-flotillin interaction in erythroid precursor cells, thereby causing lateral disorganization of raft domains. This was reflected by both reduction in the plasma membrane order and markedly decreased activation of signal transduction via the raft-dependent insulin receptor pathway. Our data highlight new molecular details concerning the mechanism whereby MPP1 functionally links flotillins to exert their physiological role in raft domain formation.
四旋蛋白是红细胞筏域的主要结构蛋白。我们之前已经表明，红细胞筏域的动态纳米级组织可能依赖于四旋蛋白-MPP1 相互作用。在这里，我们通过使用分子动力学模拟和基于表面等离子体共振的方法，确定了 MPP1 和四旋蛋白的高亲和力复合物是通过 MPP1 的 D5 结构域内的一个迄今为止尚未确定的区域形成的。重要的是，这个特定的“四旋蛋白结合基序”具有关键的生理重要性，因为含有该基序的肽的过表达抑制了红细胞前体细胞中内源性 MPP1-四旋蛋白相互作用，从而导致筏域的侧向去组织化。这反映在质膜秩序的减少和通过依赖筏的胰岛素受体途径的信号转导的显著激活减少。我们的数据突出了关于 MPP1 如何将四旋蛋白功能连接起来以发挥其在筏域形成中的生理作用的新的分子细节。
