Molecular basis for CPAP-tubulin interaction in controlling centriolar and ciliary lengthZheng, X., Ramani, A., Soni, K., Gottardo, M., Zheng, S., Ming Gooi, L., Li, W., Feng, S., Mariappan, A., Wason, A., Widlund, P., Pozniakovsky, A., Poser, I., Deng, H., Ou, G., Riparbelli, M., Giuliano, C., Hyman, A.A., Sattler, M., Gopalakrishnan, J., Li, H.
(2016) Nat Commun 7: 11874-11874
- PubMed: 27306797
- DOI: 10.1038/ncomms11874
- PubMed Abstract:
Centrioles and cilia are microtubule-based structures, whose precise formation requires controlled cytoplasmic tubulin incorporation. How cytoplasmic tubulin is recognized for centriolar/ciliary-microtubule construction remains poorly understood. Cen ...
Centrioles and cilia are microtubule-based structures, whose precise formation requires controlled cytoplasmic tubulin incorporation. How cytoplasmic tubulin is recognized for centriolar/ciliary-microtubule construction remains poorly understood. Centrosomal-P4.1-associated-protein (CPAP) binds tubulin via its PN2-3 domain. Here, we show that a C-terminal loop-helix in PN2-3 targets β-tubulin at the microtubule outer surface, while an N-terminal helical motif caps microtubule's α-β surface of β-tubulin. Through this, PN2-3 forms a high-affinity complex with GTP-tubulin, crucial for defining numbers and lengths of centriolar/ciliary-microtubules. Surprisingly, two distinct mutations in PN2-3 exhibit opposite effects on centriolar/ciliary-microtubule lengths. CPAP(F375A), with strongly reduced tubulin interaction, causes shorter centrioles and cilia exhibiting doublet- instead of triplet-microtubules. CPAP(EE343RR) that unmasks the β-tubulin polymerization surface displays slightly reduced tubulin-binding affinity inducing over-elongation of newly forming centriolar/ciliary-microtubules by enhanced dynamic release of its bound tubulin. Thus CPAP regulates delivery of its bound-tubulin to define the size of microtubule-based cellular structures using a 'clutch-like' mechanism.
Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China.,Institute for Biochemistry I and Center for Molecular Medicine of the University of Cologne, Robert-Koch-Str. 21, Cologne 50931, Germany.,MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauer Str. 108, Dresden 01307, Germany.,Biomolecular NMR at Center for Integrated Protein Science Munich and Department Chemie, Technische Universität München, Lichtenbergstr. 4, Garching 85747, Germany.,Beijing Advanced Innovation Center for Structural Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China.,Department of Life Sciences, University of Siena, Siena 53100, Italy.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.