An 8-residue sequence including a PP1 binding motif in the CTT of PC1 serves as a novel CTS. A) Amino acid sequence alignment of the 42 residues in PC1 C tail from 8 species. The 3 putative motifs are underlined in color. The 11 reported human mutations within the 42 residues are listed below the sequences. Red, definitely, highly likely, or likely pathogenic mutations; black, indeterminate mutations; blue, likely neutral mutations. B) Schematic representation of CD16.7-ΔN44ΔC112 and CD16.7 fused with each of the 3 motifs. C) Expression of indicated constructs in B in the primary cilia of IMCD3 cells. Cells were stained by antibodies against CD16 (green) and acetylated α-tubulin (Ac-α-tub; red). Scale bar, 10 μm. D) Quantification of percentage of CD16-positive cilia in cells. Error bars represent the sd between microscope fields from ≥3 independent experiments. ****P < 0.0001 compared with CD16.7-ΔN44ΔC112 control.