Crosstalk between peroxisomes, endoplasmic reticulum and endosomes during polar growth and development in fungi

• Applicants: Professor Dr. Michael Bölker; Professor Dr. Michael Feldbrügge
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 351340304

• Final Report Year: 2022

Final Report Abstract

The interaction and function of organelles like peroxisomes, the endoplasmic reticulum and endosomes are all crucial to orchestrate polar growth and development in fungi. Endosomes function as multipurpose platforms transporting peroxisomes, mRNAs, ribosomes and protein complexes like septins. Important players for endosomal transport are proteins containing PAM2 proteins like the endosomal adaptor protein Upa1 that links the key RNA-binding protein Rrm4 to endosomes. Here, Upa9/Pex3 and Upa2 were studied in detail. This revealed that Upa9/Pex3 is a peroxisomal protein co-transported with peroxisomes on endosomes but its PAM2 motif was dispensable for its function during hyphal growth. Upa2 is a multi PAM2-containing protein that was identified as a novel core component of endosomal mRNA transport. It contains a novel effector domain at its N-terminus and a GWW motif for endosomal attachment at its C-terminus. Phylogenetic and functional studies revealed that the core complex, consisting of Rrm4, Upa1 and Upa2, is restricted to Basidiomycota. However, endosomal mRNA transport with related components is most likely present in all fungal clades including Mucoromycota and Ascomycota. Recent evidence also disclosed endosomal mRNA transport and endosome-coupled translation in plants and animals indicating an ancient conserved process. Peroxisomes play a key role in fungal development and are critical for filament formation and virulence in various fungal species including the model basidiomycete Ustilago maydis. In the course of this project a series of novel CRISPR/Cas mutants were identified, in which peroxisomal metabolism and fungal development was impaired. Two novel import receptors for peroxisomal matrix proteins were characterized. This analysis revealed several targeting pathways for peroxisomal matrix proteins. These results are likely to be transferable to other biological systems. Furthermore, two novel mechanisms for dual targeting of peroxisomal proteins were identified. One of these mechanisms involves mitochondrial transit of the protein phosphatase Ptc5 en route to peroxisomes. These data contribute to a better understanding of how these two central metabolic organelles interact with each other.

Publications

• Core components of endosomal mRNA transport are evolutionarily conserved in fungi. Fungal Genetics and Biology, 126, 12-16.
  Müller, Jessica; Pohlmann, Thomas & Feldbrügge, Michael
  
• Inside-Out: From Endosomes to Extracellular Vesicles in Fungal RNA Transport. (2019, 11, 18). American Geophysical Union (AGU).
  Kwon, Seomun; Tisserant, Constance; Tulinski, Markus; Weiberg, Arne & Feldbrügge, Michael
  
• Membrane-Associated RNA-Binding Proteins Orchestrate Organelle-Coupled Translation. Trends in Cell Biology, 29(2), 178-188.
  Béthune, Julien; Jansen, Ralf-Peter; Feldbrügge, Michael & Zarnack, Kathi
  
• The multi PAM 2 protein Upa2 functions as novel core component of endosomal mRNA transport. EMBO reports, 20(9).
  Jankowski; Silke; Pohlmann; Thomas; Baumann; Sebastian; Müntjes; Kira; Devan; Senthil, Kumar; Zander; Sabrina; Feldbrügge & Michael
  
• Non-AUG Translation Initiation Generates Peroxisomal Isoforms of 6-Phosphogluconate Dehydrogenase in Fungi. Frontiers in Cell and Developmental Biology, 8 (2020, 5, 5).
  Kremp, Marco; Bittner, Elena; Martorana, Domenica; Klingenberger, Alexander; Stehlik, Thorsten; Bölker, Michael & Freitag, Johannes
  
• Peroxisomal targeting of a protein phosphatase type 2C via mitochondrial transit. Nature Communications, 11(1).
  Stehlik, Thorsten; Kremp, Marco; Kahnt, Jörg; Bölker, Michael & Freitag, Johannes
  
• The STRIPAK signaling complex regulates dephosphorylation of GUL1, an RNA-binding protein that shuttles on endosomes. PLOS Genetics, 16(9), e1008819.
  Stein, Valentina; Blank-Landeshammer, Bernhard; Müntjes, Kira; Märker, Ramona; Teichert, Ines; Feldbrügge, Michael; Sickmann, Albert & Kück, Ulrich
  
• Deletion of the natural inhibitory protein Inh1 in Ustilago maydis has no effect on the dimeric state of the F1FO-ATP synthase but increases the ATPase activity and reduces the stability. Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1862(7), 148429.
  Lucero, Romero-Aguilar; Mercedes, Esparza-Perusquía; Thorsten, Langner; Giovanni, García-Cruz; Michael, Feldbrügge; Guadalupe, Zavala; Pablo, Pardo Juan; Federico, Martínez & Oscar, Flores-Herrera
  
• Linking transport and translation of mRNAs with endosomes and mitochondria. EMBO reports, 22(10).
  Müntjes, Kira; Devan, Senthil Kumar; Reichert, Andreas S & Feldbrügge, Michael
  
• Versatile CRISPR/Cas9 Systems for Genome Editing in Ustilago maydis. Journal of Fungi, 7(2), 149.
  Wege, Sarah-Maria; Gejer, Katharina; Becker, Fabienne; Bölker, Michael; Freitag, Johannes & Sandrock, Björn
  
• Functional Analysis of the Plasma Membrane H+-ATPases of Ustilago maydis. Journal of Fungi, 8(6), 550.
  Vázquez-Carrada, Melissa; Feldbrügge, Michael; Olicón-Hernández, Dario Rafael; Guerra-Sánchez, Guadalupe & Pardo, Juan Pablo
  
• Two Pex5 Proteins With Different Cargo Specificity Are Critical for Peroxisome Function in Ustilago maydis. Frontiers in Cell and Developmental Biology, 10 (2022, 5, 12).
  Ast, Julia; Bäcker, Nils; Bittner, Elena; Martorana, Domenica; Ahmad, Humda; Bölker, Michael & Freitag, Johannes