A MademoiseLLE domain binding platform links the key RNA transporter to endosomes.
Devan, S.K., Schott-Verdugo, S., Muntjes, K., Bismar, L., Reiners, J., Hachani, E., Schmitt, L., Hoppner, A., Smits, S.H., Gohlke, H., Feldbrugge, M.(2022) PLoS Genet 18: e1010269-e1010269
- PubMed: 35727840 
- DOI: https://doi.org/10.1371/journal.pgen.1010269
- Primary Citation of Related Structures:  
7PZE - PubMed Abstract: 
Spatiotemporal expression can be achieved by transport and translation of mRNAs at defined subcellular sites. An emerging mechanism mediating mRNA trafficking is microtubule-dependent co-transport on shuttling endosomes. Although progress has been made in identifying various components of the endosomal mRNA transport machinery, a mechanistic understanding of how these RNA-binding proteins are connected to endosomes is still lacking. Here, we demonstrate that a flexible MademoiseLLE (MLLE) domain platform within RNA-binding protein Rrm4 of Ustilago maydis is crucial for endosomal attachment. Our structure/function analysis uncovered three MLLE domains at the C-terminus of Rrm4 with a functionally defined hierarchy. MLLE3 recognises two PAM2-like sequences of the adaptor protein Upa1 and is essential for endosomal shuttling of Rrm4. MLLE1 and MLLE2 are most likely accessory domains exhibiting a variable binding mode for interaction with currently unknown partners. Thus, endosomal attachment of the mRNA transporter is orchestrated by a sophisticated MLLE domain binding platform.
Organizational Affiliation: 
Institute of Microbiology, Heinrich Heine University Düsseldorf, Cluster of Excellence on Plant Sciences, Düsseldorf, Germany.