Although hundreds of cytosolic or transmembrane molecules form the primary cilium, few secreted molecules are known to contribute to ciliogenesis. Here, homologous secreted metalloproteases ADAMTS9 and ADAMTS20 are identified as ciliogenesis regulators that act intracellularly. Secreted and furin-processed ADAMTS9 bound heparan sulfate and was internalized by LRP1, LRP2 and clathrin-mediated endocytosis to be gathered in Rab11 vesicles with a unique periciliary localization defined by super-resolution microscopy. CRISPR-Cas9 inactivation of ADAMTS9 impaired ciliogenesis in RPE-1 cells, which was restored by catalytically active ADAMTS9 or ADAMTS20 acting in trans, but not by their proteolytically inactive mutants. Their mutagenesis in mice impaired neural and yolk sac ciliogenesis, leading to morphogenetic anomalies resulting from impaired hedgehog signaling, which is transduced by primary cilia. In addition to their cognate extracellular proteolytic activity, ADAMTS9 and ADAMTS20 thus have an additional proteolytic role intracellularly, revealing an unexpected regulatory dimension in ciliogenesis.
Bibliographical noteFunding Information:
Funding was provided by the NIH-NHLBI Program of Excellence in Glycosciences award HL107147 and NIH-NEI award EY024943 to S.S.A. and the David and Lindsay Morgenthaler Postdoctoral Fellowship and the Mark Lauer Pediatric Research Grant to S. N. This research was supported by the Allen Distinguished Investigator Program, through support made by The Paul G. Allen Frontiers Group and the American Heart Association to S.S.A. This work utilized a Leica SP8 confocal microscope that was purchased with funding from National Institutes of Health SIG grant 1S10OD019972-01. We thank Apte laboratory members and Dr. Jeremy Reiter for valuable discussions, Johanne Dubail and Rahel Schnellmann for ADAMTS9 and ADAMTS16 plasmids, Judy Drazba and Mei Yin of the Lerner Research Institute Imaging Core for guidance with microscopy, and Dave Schumick of the LRI Medical Art and Photography department for Figs. 4l, m, 10.
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)