Phosphatidylinositol phosphate kinase PIPKIγ and phosphatase INPP5E coordinate initiation of ciliogenesis

Nat Commun. 2016 Feb 26:7:10777. doi: 10.1038/ncomms10777.

Abstract

Defective primary cilia are causative to a wide spectrum of human genetic disorders, termed ciliopathies. Although the regulation of ciliogenesis is intensively studied, how it is initiated remains unclear. Here we show that type Iγ phosphatidylinositol 4-phosphate (PtdIns(4)P) 5-kinase (PIPKIγ) and inositol polyphosphate-5-phosphatase E (INPP5E), a Joubert syndrome protein, localize to the centrosome and coordinate the initiation of ciliogenesis. PIPKIγ counteracts INPP5E in regulating tau-tubulin kinase-2 (TTBK2) recruitment to the basal body, which promotes the removal of microtubule capping protein CP110 and the subsequent axoneme elongation. Interestingly, INPP5E and its product--PtdIns(4)P--accumulate at the centrosome/basal body in non-ciliated, but not ciliated, cells. PtdIns(4)P binding to TTBK2 and the distal appendage protein CEP164 compromises the TTBK2-CEP164 interaction and inhibits the recruitment of TTBK2. Our results reveal that PtdIns(4)P homoeostasis, coordinated by PIPKIγ and INPP5E at the centrosome/ciliary base, is vital for ciliogenesis by regulating the CEP164-dependent recruitment of TTBK2.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Centrosome / metabolism*
  • Cilia / metabolism*
  • Cilia / ultrastructure
  • HEK293 Cells
  • Humans
  • Immunoprecipitation
  • Mice
  • Microscopy, Electron, Scanning
  • Microscopy, Electron, Transmission
  • Microscopy, Fluorescence
  • Morphogenesis / genetics*
  • NIH 3T3 Cells
  • Phosphoric Monoester Hydrolases / genetics*
  • Phosphoric Monoester Hydrolases / metabolism
  • Phosphotransferases (Alcohol Group Acceptor) / genetics*
  • Protein Serine-Threonine Kinases / metabolism

Substances

  • Phosphotransferases (Alcohol Group Acceptor)
  • tau-tubulin kinase
  • 1-phosphatidylinositol-4-phosphate 5-kinase
  • Protein Serine-Threonine Kinases
  • Phosphoric Monoester Hydrolases
  • phosphoinositide 5-phosphatase