Identification of focal adhesion kinase (FAK) and phosphatidylinositol 3-kinase (PI3-kinase) as Par3 partners by proteomic analysis

Norimichi Itoh, Masanori Nakayama, Takashi Nishimura, Shin Fujisue, Tomoki Nishioka, Takashi Watanabe, Kozo Kaibuchi

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Partition defective 3 (Par3) is involved in a variety of polarity events including establishment of apico-basal polarity of epithelial cell, axon/dendrite specification of neurons and directional migration of cells with front-rear polarity. Par3 is thought to regulate cell polarity as a scaffold protein by interacting with various partner proteins such as Par6, aPKC, Tiam1/2 and Numb. However, the mode of actions of Par3 in polarized migration remains largely unknown. To explore Par3 functions, we screened Par3-interacting proteins by combining Par3 affinity column chromatography and shotgun analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS). We obtained about two hundred Par3- interacting proteins from the rat brain cytosol fraction. Among them, we focused on FAK and PI3-kinase, as both of them participate in directional cell migration. FAK associated with the PDZ domain and the coiled-coil region of Par3 and p110 of PI3-kinase associated with the coiled-coil region of Par3. Par3 was partially colocalized with FAK in spreading cells. Depletion of Par3 by RNA interference inhibited adhesion-induced activation of FAK and PI3-kinase, and RNA interference-resistant Par3 restored the inhibitory effects. In addition, Par3 was required for the adhesion-induced cell spreading as well as for directional cell migration toward collagen. These results suggest that Par3 directly interacts with FAK and PI3-kinase, enhancing their activities for polarized cell migration.

Original languageEnglish
Pages (from-to)297-308
Number of pages12
Issue number5
Publication statusPublished - May 2010
Externally publishedYes


  • Cell-ECM adhesion
  • LC-MS/MS
  • Polarized cell migration
  • Proteomics
  • Shotgun analysis

ASJC Scopus subject areas

  • Structural Biology
  • Cell Biology


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