Ubiquitinated proteins increase dramatically in the flagella of retrograde IFT mutants. (A) Flagella of three retrograde IFT mutants, fla16, d1blic, and dhc1b^ts, were isolated at the permissive temperature and analyzed on immunoblots probed for ubiquitin (Ub). α-Tubulin was used as a loading control. (B) The amounts of ubiquitinated proteins in flagella were compared directly on a single immunoblot. The samples were flagella induced to resorb (Res) in wild-type (WT) cells with high Na⁺/no-Ca²⁺ medium for the indicated times (minutes), flagella induced to resorb in fla10 by incubation at 32°C for the indicated times, and flagella of the retrograde IFT mutant d1blic isolated at the permissive temperature. Molecular masses are given in kilodaltons.