The ciliary rootlet maintains long-term stability of sensory cilia.
The striated ciliary rootlet is a prominent cytoskeleton originating from basal bodies of ciliated cells. Although a familiar structure in cell biology, its function has remained unresolved. In this study, we carried out targeted disruption in mice of the gene for rootletin, a component of the rootlet. In the mutant, ciliated cells are devoid of rootlets. Phototransduction and ciliary beating in sensory and motile cilia initially exhibit no apparent functional deficits. However, photoreceptors degenerate over time, and mutant lungs appear prone to pathological changes consistent with insufficient mucociliary clearance. Further analyses revealed a striking fragility at the ciliary base in photoreceptors lacking rootlets. In vitro assays suggest that the rootlet is among the least dynamic of all cytoskeletons and interacts with actin filaments. Thus, a primary function of the rootlet is to provide structural support for the cilium. Inasmuch as photoreceptors elaborate an exceptionally enlarged sensory cilium, they are especially dependent on the rootlet for structural integrity and long-term survival.
Yang
Jun
J
The Berman-Gund Laboratory for the Study of Retinal Degenerations, Howe Laboratory, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
Gao
Jiangang
J
Adamian
Michael
M
Wen
Xiao-Hong
XH
Pawlyk
Basil
B
Zhang
Luo
L
Sanderson
Michael J
MJ
Zuo
Jian
J
Makino
Clint L
CL
Li
Tiansen
T
D000818:Animals; D002502:Centrioles / Q000502:physiology; D002923:Cilia / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000172:deficiency / Q000235:genetics; D003599:Cytoskeleton / Q000502:physiology*; D007700:Kinetics; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology; D051379:Mice; D009154:Mutation / Q000235:genetics; D015388:Organelles / Q000502:physiology; D020419:Photoreceptor Cells, Vertebrate / Q000166:cytology / Q000502:physiology; D012162:Retinal Degeneration; D013997:Time Factors
C469436:Crocc protein, mouse; D003598:Cytoskeletal Proteins