Primary cilia are microtubule-based sensory organelles that organize numerous key signals during developments and tissue homeostasis. Ciliary microtubule doublet, named axoneme, is grown directly from the distal end of mother centrioles through a multistep process upon cell cycle exit; however, the instructive signals that initiate these events are poorly understood. Here we show that ubiquitin-proteasome machinery removes trichoplein, a negative regulator of ciliogenesis, from mother centrioles and thereby causes Aurora-A inactivation, leading to ciliogenesis. Ciliogenesis is blocked if centriolar trichoplein is stabilized by treatment with proteasome inhibitors or by expression of non-ubiquitylatable trichoplein mutant (K50/57R). Started from two-stepped global E3 screening, we have identified KCTD17 as a substrate-adaptor for Cul3-RING E3 ligases (CRL3s) that polyubiquitylates trichoplein. Depletion of KCTD17 specifically arrests ciliogenesis at the initial step of axoneme extension through aberrant trichoplein-Aurora-A activity. Thus, CRL3-KCTD17 targets trichoplein to proteolysis to initiate the axoneme extension during ciliogenesis.

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(K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3 (LF4) thick films were directly prepared on glass, stainless-steel and Pt/Ti/ZrO2 substrates at room temperature by the aerosol deposition method (ADM). The effects of moisture content in the starting powder and postdeposition annealing temperature on the dielectric properties of LF4 film were investigated. The LF4 film prepared using preheated powder (moisture content of 0.006%) has dielectric properties with high stability at increasing frequencies, whereas the LF4 film prepared with non-preheated powders (0.21%) has a dielectric constant that decreases abruptly at higher frequencies. When the postdeposition annealing temperature of the film was 600 °C, the dielectric constant increased from 200 to 343 at 1 MHz with increasing preheating temperature from 150 to 1100 °C. Also, the dielectric constant of the film increased from 231 to 559 with increasing annealing temperature from 400 to 1000 °C. These results strongly indicate that moisture elimination in starting powders through preheating and postdeposition annealing for ADM plays an important role in realizing good dielectric properties of LF4 film for practical application as lead-free piezoelectric ceramics. Also, the Curie temperature (Tc) of the deposited LF4 film was 250 °C.

SummaryChk1 inhibits the premature activation of the cyclin-B1-Cdk1. However, it remains controversial whether Chk1 inhibits Cdk1 in the centrosome or in the nucleus before the G2-M transition. In this study, we examined the specificity of the mouse monoclonal antiChk1 antibody DCS-310, with which the centrosome was stained. Conditional Chk1 knockout in mouse embryonic fibroblasts reduced nuclear but not centrosomal staining with DCS-310. In Chk1 +/myc human colon adenocarcinoma (DLD-1) cells, Chk1 was detected in the nucleus but not in the centrosome using an anti-Myc antibody. Through the combination of protein array and RNAi technologies, we identified Ccdc-151 as a protein that crossreacted with DCS-310 on the centrosome. Mitotic entry was delayed by expression of the Chk1 mutant that localized in the nucleus, although forced immobilization of Chk1 to the centrosome had little impact on the timing of mitotic entry. These results suggest that nuclear but not centrosomal Chk1 contributes to correct timing of mitotic entry.