CEP120 interacts with C2CD3 and Talpid3 and is required for centriole appendage assembly and ciliogenesis

Jhih-Jie Tsai,Tang K Tang,Ching-Wen Chang,Jia-Hua Liu,Wen-Bin Hsu

doi:10.1038/s41598-019-42577-0

Jhih-Jie Tsai, Tang K Tang + Show 3 more

Open Access

https://doi.org/10.1038/s41598-019-42577-0

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Abstract

Centrosomal protein 120 (CEP120) was originally identified as a daughter centriole-enriched protein that participates in centriole elongation. Recent studies showed that CEP120 gene mutations cause complex ciliopathy phenotypes in humans, including Joubert syndrome and Jeune asphyxiating thoracic dystrophy, suggesting that CEP120 plays an additional role in ciliogenesis. To investigate the potential roles of CEP120 in centriole elongation and cilia formation, we knocked out the CEP120 gene in p53-deficient RPE1 cells using the CRISPR/Cas9 editing system, and performed various analyses. We herein report that loss of CEP120 produces short centrioles with no apparent distal and subdistal appendages. CEP120 knockout was also associated with defective centriole elongation, impaired recruitment of C2CD3 and Talpid3 to the distal ends of centrioles, and consequent defects in centriole appendage assembly and cilia formation. Interestingly, wild-type CEP120 interacts with C2CD3 and Talpid3, whereas a disease-associated CEP120 mutant (I975S) has a low affinity for C2CD3 binding and perturbs cilia assembly. Together, our findings reveal a novel role of CEP120 in ciliogenesis by showing that it interacts with C2CD3 and Talpid3 to assemble centriole appendages and by illuminating the molecular mechanism through which the CEP120 (I975S) mutation causes complex ciliopathies.

Highlights

Centrosomal protein 120 (CEP120) was originally identified as a daughter centriole-enriched protein that participates in centriole elongation
We previously showed that myosin-Va mediates the transportation of preciliary vesicles (PCVs) to the distal appendages (DAs) of a mother centriole as the earliest event that defines the onset of ciliogenesis[6]
We are just starting to understand the molecular mechanism through which an immature centriole acquires DAs and subdistal appendages (SDAs) to become a mature mother centriole

Summary

Introduction

Centrosomal protein 120 (CEP120) was originally identified as a daughter centriole-enriched protein that participates in centriole elongation. A nascent centriole (daughter centriole) starts to grow from the proximal end of a pre-existing centriole (mother centriole) in G1 phase of cell cycle, elongates through the S and G2 phases, and reaches its full length at early mitosis In this cell cycle, the daughter centriole has not yet acquired subdistal appendages (SDAs) and distal appendages (DAs), cannot be basal body for primary cilia, but can produce new daughter centriole near the proximal end[1,2,3,4,5]. These PCVs fuse with other incoming PCVs to form a large ciliary vesicle through the membrane shaping proteins EHD1 and EHD37 This initial step that converts the mother centriole into a basal body, is followed by removal of the centriolar coiled coil protein 110 (CP110) that caps the distal end of the mother centriole, the assembly of ciliary transition zone, and the growth of axoneme microtubules during ciliogenesis[8]. A very recent report showed that Talpid[3] is physically associated with C2CD3 at the distal ends of centrioles and such an association is essential for centriole maturation and DA assembly[23]

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