Super-resolution microscopy reveals coupling between mammalian centriole subdistal appendages and distal appendages.

Subdistal appendages (sDAPs) are centriolar elements observed proximal to the distal appendages (DAPs) in vertebrates. Despite their obvious presence, structural and functional understanding of sDAPs remains elusive. Here, by combining super-resolved localization analysis and CRISPR-Cas9 genetic perturbation, we find that, although DAPs and sDAPs are primarily responsible for distinct functions in ciliogenesis and microtubule anchoring respectively, the presence of one element actually affects the positioning of the other. Specifically, we find dual layers of both ODF2 and CEP89, where their localizations are differentially regulated by DAP and sDAP integrity. DAP depletion relaxes longitudinal occupancy of sDAP protein ninein to cover the DAP region, implying a role of DAPs in sDAP positioning. Removing sDAPs alter the distal border of centrosomal gamma-tubulins, illustrating a new role of sDAPs. Together, our results provide an architectural framework of sDAPs to shed light on functional understanding, surprisingly revealing the coupling between DAPs and sDAPs.