Spatial control of translation repression and polarized growth by conserved NDR kinase Orb6 and RNA-binding protein Sts5
Illyce Nuñez,
Marbelys Rodriguez Pino,
David J Wiley,
Maitreyi E Das,
Chuan Chen,
Tetsuya Goshima,
Kazunori Kume,
Dai Hirata,
Takashi Toda,
Fulvia Verde
Affiliations
Illyce Nuñez
Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
Marbelys Rodriguez Pino
Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
David J Wiley
Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
Maitreyi E Das
Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, United States
Chuan Chen
Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
Tetsuya Goshima
National Research Institute of Brewing, Higashi-Hiroshima, Japan
Kazunori Kume
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan
Dai Hirata
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan
Takashi Toda
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan; The Francis Crick Institute, Lincoln’s Inn Fields Laboratory, London, United Kingdom
Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States; Marine Biological Laboratory, Woods Hole, United States
RNA-binding proteins contribute to the formation of ribonucleoprotein (RNP) granules by phase transition, but regulatory mechanisms are not fully understood. Conserved fission yeast NDR (Nuclear Dbf2-Related) kinase Orb6 governs cell morphogenesis in part by spatially controlling Cdc42 GTPase. Here we describe a novel, independent function for Orb6 kinase in negatively regulating the recruitment of RNA-binding protein Sts5 into RNPs to promote polarized cell growth. We find that Orb6 kinase inhibits Sts5 recruitment into granules, its association with processing (P) bodies, and degradation of Sts5-bound mRNAs by promoting Sts5 interaction with 14-3-3 protein Rad24. Many Sts5-bound mRNAs encode essential factors for polarized cell growth, and Orb6 kinase spatially and temporally controls the extent of Sts5 granule formation. Disruption of this control system affects cell morphology and alters the pattern of polarized cell growth, revealing a role for Orb6 kinase in the spatial control of translational repression that enables normal cell morphogenesis.
