The multi PAM2 protein Upa2 functions as novel core component of endosomal mRNA transport
The multi PAM2 protein Upa2 functions as novel core component of endosomal mRNA transport
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DOI：
10.15252/embr.201847381
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发表时间：
2019-07-24
期刊：
影响因子：
7.7
通讯作者：
Feldbruegge, Michael
中科院分区：
文献类型：
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作者：
Jankowski, Silke;Pohlmann, Thomas;Feldbruegge, Michael
mRNA转运决定了蛋白的时空表达。运输单元是含有货物mrna、rna结合蛋白和辅助蛋白的高阶核糖核蛋白复合物。真菌菌丝内体mRNA转运是目前研究最多的易位机制。虽然有几个因素是已知的，但还缺少其他核心组件。在这里，我们将含有多个PAM2基序（poly[A]-binding protein [Pab1]-associated motif 2）的232 kDa蛋白Upa2描述为一个新的核心成分。Upa2的缺失扰乱了货物mrna和相关Pab1的运输。Upa2以mrna依赖的方式存在于几乎所有转运核内体中。令人惊讶的是，所有四个PAM2基序在单极菌丝生长过程中都是必不可少的。相反，Upa2含有一个新的n端效应域，作为重要的功能决定因素，以及一个c端GWW基序，用于特定的内体定位。本质上，Upa2符合内体mRNA运输的新核心成分的所有标准，并似乎执行关键的支架功能。
mRNA transport determines spatiotemporal protein expression. Transport units are higher-order ribonucleoprotein complexes containing cargo mRNAs, RNA-binding proteins and accessory proteins. Endosomal mRNA transport in fungal hyphae belongs to the best-studied translocation mechanisms. Although several factors are known, additional core components are missing. Here, we describe the 232 kDa protein Upa2 containing multiple PAM2 motifs (poly[A]-binding protein [Pab1]-associated motif 2) as a novel core component. Loss of Upa2 disturbs transport of cargo mRNAs and associated Pab1. Upa2 is present on almost all transport endosomes in an mRNA-dependent manner. Surprisingly, all four PAM2 motifs are dispensable for function during unipolar hyphal growth. Instead, Upa2 harbours a novel N-terminal effector domain as important functional determinant as well as a C-terminal GWW motif for specific endosomal localisation. In essence, Upa2 meets all the criteria of a novel core component of endosomal mRNA transport and appears to carry out crucial scaffolding functions.