Interaction between the Caenorhabditis elegans centriolar protein SAS-5 and microtubules facilitates organelle assembly.

Sarah BianchiΨ, Kacper B RogalaΨ, Nicola J DynesΨ, Manuel Hilbert, Sebastian A Leidel, Michel O Steinmetz, Pierre Gönczy, Ioannis Vakonakis.

Molecular Biology of the Cell. 29(6):722-735. 2018 March 15.

blue & bold — Rogala Lab member
Ψ — equal contribution
@ — corresponding author

Centrioles are microtubule-based organelles that organize the microtubule network and seed the formation of cilia and flagella. New centrioles assemble through a stepwise process dependent notably on the centriolar protein SAS-5 in Caenorhabditis elegans SAS-5 and its functional homologues in other species form oligomers that bind the centriolar proteins SAS-6 and SAS-4, thereby forming an evolutionarily conserved structural core at the onset of organelle assembly. Here, we report a novel interaction of SAS-5 with microtubules. Microtubule binding requires SAS-5 oligomerization and a disordered protein segment that overlaps with the SAS-4 binding site. Combined in vitro and in vivo analysis of select mutants reveals that the SAS-5-microtubule interaction facilitates centriole assembly in C. elegans embryos. Our findings lead us to propose that the interdependence of SAS-5 oligomerization and microtubule binding reflects an avidity mechanism, which also strengthens SAS-5 associations with other centriole components and, thus, promotes organelle assembly.

 

PubMed: 29367435 // Journal website [open access]