The tip CP has a different structure from the main CP. (A) Subtomogram average of the main CP. (B) Subtomogram average of the tip CP. In A and B, structures are lowpass-filtered to 20 Å to be comparable. Microtubules are in gray and projections are colored. (C) Graph of the distance between C1 and C2 microtubules. The reference on the x-axis is the middle of the narrowing zone. The average is shown as a thick blue line. The standard deviation is shown in light blue (n = 5 cilia). (D) Subtomogram average of the tip CP. Microtubules are colored according to tubulin subunits. α-tubulin is colored in green and β-tubulin is colored in blue. C1 is on the left and C2 is on the right. The yellow stars indicate the seams. (E and F) Side view of the tip CP as shown in D. (G) Tip CP rendering showing the MIPs in purple and yellow. The microtubules are white and protofilaments are numbered from the seam. The yellow stars indicate the seams.