Sas4 links basal bodies to cell division via Hippo signaling

J Cell Biol. 2020 Aug 3;219(8):e201906183. doi: 10.1083/jcb.201906183.

Abstract

Basal bodies (BBs) are macromolecular complexes required for the formation and cortical positioning of cilia. Both BB assembly and DNA replication are tightly coordinated with the cell cycle to ensure their accurate segregation and propagation to daughter cells, but the mechanisms ensuring coordination are unclear. The Tetrahymena Sas4/CPAP protein is enriched at assembling BBs, localizing to the core BB structure and to the base of BB-appendage microtubules and striated fiber. Sas4 is necessary for BB assembly and cortical microtubule organization, and Sas4 loss disrupts cell division furrow positioning and DNA segregation. The Hippo signaling pathway is known to regulate cell division furrow position, and Hippo molecules localize to BBs and BB-appendages. We find that Sas4 loss disrupts localization of the Hippo activator, Mob1, suggesting that Sas4 mediates Hippo activity by promoting scaffolds for Mob1 localization to the cell cortex. Thus, Sas4 links BBs with an ancient signaling pathway known to promote the accurate and symmetric segregation of the genome.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Basal Bodies / metabolism*
  • Basal Bodies / ultrastructure
  • Cell Division*
  • Centrioles / genetics
  • Centrioles / metabolism*
  • Centrioles / ultrastructure
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • Signal Transduction
  • Tetrahymena thermophila / genetics
  • Tetrahymena thermophila / metabolism*
  • Tetrahymena thermophila / ultrastructure
  • Time Factors

Substances

  • Microtubule-Associated Proteins
  • Protozoan Proteins
  • Protein Serine-Threonine Kinases