2. Academic Validation
  3. Molecular basis for CPAP-tubulin interaction in controlling centriolar and ciliary length

Molecular basis for CPAP-tubulin interaction in controlling centriolar and ciliary length

  • Nat Commun. 2016 Jun 16;7:11874. doi: 10.1038/ncomms11874.
Xiangdong Zheng 1 2 3,  Anand Ramani 4,  Komal Soni 5 6,  Marco Gottardo 7,  Shuangping Zheng 1 2,  Li Ming Gooi 4,  Wenjing Li 2 3,  Shan Feng 2 3,  Aruljothi Mariappan 4,  Arpit Wason 4,  Per Widlund 8,  Andrei Pozniakovsky 8,  Ina Poser 8,  Haiteng Deng 2,  Guangshuo Ou 2 3,  Maria Riparbelli 7,  Callaini Giuliano 7,  Anthony A Hyman 8,  Michael Sattler 5 6,  Jay Gopalakrishnan 4,  Haitao Li 1 2 9
Affiliations

Affiliations

  • 1 Beijing Advanced Innovation Center for Structural Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China.
  • 2 MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
  • 3 Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China.
  • 4 Institute for Biochemistry I and Center for Molecular Medicine of the University of Cologne, Robert-Koch-Str. 21, Cologne 50931, Germany.
  • 5 Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.
  • 6 Biomolecular NMR at Center for Integrated Protein Science Munich and Department Chemie, Technische Universität München, Lichtenbergstr. 4, Garching 85747, Germany.
  • 7 Department of Life Sciences, University of Siena, Siena 53100, Italy.
  • 8 Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauer Str. 108, Dresden 01307, Germany.
  • 9 Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.
PMID: 27306797 DOI: 10.1038/ncomms11874
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. 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.

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