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The multi PAM 2 protein Upa2 functions as novel core component of endosomal mRNA transport
Author(s) -
Jankowski Silke,
Pohlmann Thomas,
Baumann Sebastian,
Müntjes Kira,
Devan Senthil Kumar,
Zander Sabrina,
Feldbrügge Michael
Publication year - 2019
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201847381
Subject(s) - endosome , microbiology and biotechnology , messenger rna , chemistry , component (thermodynamics) , biology , biochemistry , gene , physics , intracellular , thermodynamics
mRNA transport determines spatiotemporal protein expression. Transport units are higher‐order ribonucleoprotein complexes containing cargo mRNA s, 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 PAM 2 motifs (poly[A]‐binding protein [Pab1]‐associated motif 2) as a novel core component. Loss of Upa2 disturbs transport of cargo mRNA s and associated Pab1. Upa2 is present on almost all transport endosomes in an mRNA ‐dependent manner. Surprisingly, all four PAM 2 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.