Figure 3

Nucleoporins in cilia and nuclei. Nuclear pore complexes (red donuts in nuclear envelope) contain nucleoporin proteins that assemble into subcomplexes (center). Some nucleoporin subcomplexes also localize to the transition zone where they are postulated to form a ciliary pore complex (red donuts at ciliary base). Two possible structural configurations of the nucleoporins at the base of the cilium are presented. (A) Model in which nucleoporins assemble into one large pore at the base of the cilium with the axoneme protruding through the middle of the pore. (B) Model in which nucleoporins assemble into nine pores at the base of the cilium with each pore positioned between the Y-links. (C) Electron cryotomography analysis of isolated basal body structures from the protist Tetrahymena pyriformis indicates nine pore structures adjacent to the microtubule axonemes. FG, phenylalanine-glycine. Reprinted from Ounjai et al. [35], with permission from Elsevier.