Regulation of primary cilia formation by ceramide.
The primary cilium is an important sensory organelle, the regulation of which is not fully understood. We found that in polarized Madin-Darby Canine Kidney cells, the sphingolipid ceramide is specifically distributed to a cis-Golgi compartment at the base of the primary cilium. This compartment immunostained for the centrosome marker gamma-tubulin, the Rho type GTPase cell division cycle 42 (Cdc42), and atypical protein kinase Czeta/lambda (aPKC), a kinase activated by ceramide and associated with a polarity protein complex consisting of partitioning defective (Par)6 and Cdc42. Inhibition of ceramide biosynthesis with Fumonisin B1 prevented codistribution of aPKC and Cdc42 in the centrosomal/pericentriolar compartment and severely impaired ciliogenesis. Cilium formation and codistribution of aPKC and Cdc42 were restored by incubation with N-acetyl or N-palmitoyl sphingosine (C2 or C16 ceramide), or the ceramide analog N-oleoyl serinol (S18). Cilium formation was also restored by the glycogen synthase kinase-3beta (GSK-3beta) inhibitor indirubin-3-monoxime, suggesting that regulation of ciliogenesis depends on the inhibition of GSK-3beta by ceramide-activated aPKC. Consistently, inhibition of aPKC with a pseudosubstrate inhibitor prevented restoration of ciliogenesis by C2 ceramide or S18. Our data show for the first time that ceramide is required for primary cilium formation.
Wang
Guanghu
G
Program in Developmental Neurobiology, Institute of Molecular Medicine and Genetics, School of Medicine, Medical College of Georgia, Augusta, GA 30912, USA.
Krishnamurthy
Kannan
K
Bieberich
Erhard
E
D000818:Animals; D002460:Cell Line; D002518:Ceramides / Q000378:metabolism* / Q000494:pharmacology*; D002923:Cilia / Q000187:drug effects* / Q000378:metabolism*; D004285:Dogs; D037341:Fumonisins / Q000494:pharmacology; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D007150:Immunohistochemistry; D010088:Oxidoreductases / Q000037:antagonists & inhibitors
D002518:Ceramides; D037341:Fumonisins; C056933:fumonisin B1; D010088:Oxidoreductases; C108138:dihydroceramide desaturase; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3