The binding sites that guide fungal 'vesicle hitchhiking'—new study maps mRNA transport
Why it matters: Deciphering this 'hitchhiker code' reveals how fungal cells precisely organize internal logistics, impacting understanding of pathogenic fungi.
- Rrm4 protein controls mRNA transport in fungi, distinguishing important from unimportant binding sites in transported mRNAs.
- mRNA molecules act as "hitchhikers," attaching to small transport vesicles (endosomes) that move along the cytoskeleton.
- RRM1 and RRM2 domains form the essential core of the transport system, recognizing binding sites crucial for targeted fungal cell growth.
- RRM3 domain recognizes a 'postcode' motif on mRNA, forming over 10,000 bonds but proving largely dispensable for basic growth, though it can cooperatively support RRM1/RRM2.
- Disruption of mRNA transport leads to fungal disorientation and malformations instead of organized filaments, highlighting the precision of cellular logistics.
- Professor Kathi Zarnack (JMU) and Professor Michael Feldbrügge (University of Düsseldorf) led the study, published in Nucleic Acids Research.
Researchers from Julius-Maximilians-Universität Würzburg and the University of Düsseldorf have mapped the intricate mRNA transport mechanism in the pathogenic fungus Ustilago maydis, revealing how the protein Rrm4 acts as a "loading master" to guide mRNA molecules via "vesicle hitchhiking" for precise protein production. Their study identified over 50,000 binding sites, differentiating the roles of Rrm4's RRM1, RRM2, and RRM3 domains in ensuring targeted fungal growth and preventing malformations.
