The conserved centrosomal protein FOR20 is required for assembly of the transition zone and basal body docking at the cell surface.
Within the FOP family of centrosomal proteins, the conserved FOR20 protein has been implicated in the control of primary cilium assembly in human cells. To ascertain its role in ciliogenesis, we have investigated the function of its ortholog, PtFOR20p, in the multiciliated unicellular organism Paramecium. Using combined functional and cytological analyses, we found that PtFOR20p specifically localises at basal bodies and is required to build the transition zone, a prerequisite to their maturation and docking at the cell surface and hence to ciliogenesis. We also found that PtCen2p (one of the two basal body specific centrins, an ortholog of HsCen2) is required to recruit PtFOR20p at the developing basal body and to control its length. By contrast, the other basal-body-specific centrin PtCen3p is not needed for assembly of the transition zone, but is required downstream, for basal body docking. Comparison of the structural defects induced by depletion of PtFOR20p, PtCen2p or PtCen3p, respectively, illustrates the dual role of the transition zone in the biogenesis of the basal body and in cilium assembly. The multiple potential roles of the transition zone during basal body biogenesis and the evolutionary conserved function of the FOP proteins in microtubule membrane interactions are discussed.
CNRS, Centre de Génétique Moléculaire, UPR3404, 91198 Gif-sur-Yvette, France. anne.aubusson@cgm.cnrs-gif.fr
Anne
A
Aubusson-Fleury
Michel
M
Lemullois
Nicole Garreau
NG
de Loubresse
Chloé
C
Laligné
Jean
J
Cohen
Olivier
O
Rosnet
Maria
M
Jerka-Dziadosz
Janine
J
Beisson
France
F
Koll
D002462:Cell Membrane / Q000378:metabolism*; D018385:Centrosome / Q000378:metabolism*; D002923:Cilia / Q000378:metabolism / Q000648:ultrastructure; D017124:Conserved Sequence; D017125:Genes, Protozoan; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D010247:Paramecium / Q000166:cytology* / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D021381:Protein Transport; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins