The Ubiquitin Conjugation System Is Involved in the Disassembly of Cilia and Flagella

• Published in: The Journal of cell biology Vol. 186; no. 4; pp. 601 - 613
• Main Authors: Huang, Kaiyao, Diener, Dennis R., Rosenbaum, Joel L.
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 24.08.2009; The Rockefeller University Press
• Subjects: Adenosine triphosphatase; Animals; Antibodies; Biochemistry; Cell cycle; Cells; Chlamydomonas reinhardtii - cytology; Chlamydomonas reinhardtii - metabolism; Cilia; Cilia - metabolism; Cilia - ultrastructure; Enzymes; Epithelial cells; Flagella; Flagella - metabolism; Flagella - ultrastructure; Humans; Microtubules; Proteins; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Signal Transduction - physiology; Ubiquitin - metabolism; Ubiquitin-Conjugating Enzymes - genetics; Ubiquitin-Conjugating Enzymes - metabolism; Ubiquitins
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200903066

The disassembly of cilia and flagella is linked to the cell cycle and environmental cues. We have found that ubiquitination of flageliar proteins is an integral part of flageliar disassembly. Free ubiquitin and the ubiquitin-conjugating enzyme CrUbc13 are detected in flagella, and several proteins are ubiquitinated in isolated flagella when exogenous ubiquitin and adenosine triphosphatase are added, suggesting that the ubiquitin conjugation system operates in flagella. Levels of ubiquitinated flageliar proteins increase during flageliar résorption, especially in intraflagellar transport (lFF) mutants, suggesting that disassembly products are labeled with ubiquitin and transported to the cell body by lFT. Substrates of the ubiquitin conjugation system include α-tubulin (but not ß-tubulin), a dynein subunit (lC2), two signaling proteins involved in the mating process, cyclic guanosine monophosphate-dependent kinase, and the cation channel polycystic kidney disease 2. Ubiquitination of flageliar proteins is enhanced early in mating, suggesting that ubiquitination also plays an active role in regulating signaling pathways in flagella.