EHD1 promotes CP110 ubiquitination by centriolar satellite delivery of HERC2 to the mother centriole

Primary cilia are sensory organelles that coordinate diverse signaling pathways, controlling development and homeostasis. Progression beyond the early steps of ciliogenesis requires the removal of a distal end protein, CP110, from the mother centriole, a process mediated by Eps15 Homology Domain protein 1 (EHD1). We show that EHD1 regulates CP110 ubiquitination during ciliogenesis, and identify two E3 ubiquitin ligases, HECT domain and RCC1-like domain 2 (HERC2) and mindbomb homolog 1 (MIB1), that interact with and ubiquitinate CP110. We determined that HERC2 is required for ciliogenesis and localizes to centriolar satellites, which are peripheral aggregates of centriolar proteins known to regulate ciliogenesis. We reveal a role for EHD1 in the transport of centriolar satellites and HERC2 to the mother centriole during ciliogenesis. Taken together, our work showcases a mechanism whereby EHD1 controls centriolar satellite movement to the mother centriole, thus delivering the E3 ubiquitin ligase HERC2 to promote CP110 ubiquitination and degradation.

Automated summary

Primary cilia are sensory organelles that coordinate diverse signaling pathways, controlling development and homeostasis. In this study, we found that EHD1 regulates the ubiquitination of CP110, a protein required for ciliogenesis, and identified HERC2 and MIB1 as E3 ubiquitin ligases that interact with and ubiquitinate CP110. We also discovered that HERC2 is necessary for ciliogenesis and localizes to centriolar satellites, which play a role in ciliogenesis regulation. Our findings highlight a mechanism in which EHD1 controls the movement of centriolar satellites and HERC2 to the mother centriole during ciliogenesis, promoting CP110 ubiquitination and degradation.