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  • The EMBO Journal (1999) 18, 3909 - 3923
  • doi:10.1093/emboj/18.14.3909

PKCalpha regulates bold beta1 integrin-dependent cell motility through association and control of integrin traffic

Tony Ng1, David Shima2, Anthony Squire3, Philippe I.H. Bastiaens3, Steve Gschmeissner4, Martin J. Humphries5 and Peter J. Parker1

  1. Protein Phosphorylation Laboratory, London WC2A 3PX, UK
  2. Cell Biology Laboratory, London WC2A 3PX, UK
  3. Cell Biophysics Laboratory, London WC2A 3PX, UK
  4. Electron Microscopy Unit, Imperial Cancer Research Fund, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
  5. Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK

Correspondence to:

Peter J. Parker, E-mail: p.parker@icrf.icnet.uk

Received 15 April 1999; Accepted 21 May 1999; Revised 21 May 1999

Protein kinase C (PKC) has been implicated in integrin-mediated spreading and migration. In mammary epithelial cells there is a partial co-localization between beta1 integrin and PKCalpha. This reflects complexes between these proteins as demonstrated by fluorescense resonance energy transfer (FRET) monitored by fluorescence lifetime imaging microscopy and also by coprecipitation. Constitutive complexes are observed for the intact PKCalpha and also form with the regulatory domain in an activation-dependent manner. Expression of PKCalpha causes upregulation of beta1 integrin on the cell surface, whereas stimulation of PKC induces internalization of beta1 integrin. The integrin initially traffics to an endosomal compartment in a Ca2+/PI 3-kinase/dynamin I-dependent manner and subsequently enters an endocytic recycling pathway. This induction of endocytosis by PKCalpha is a function of activity and is not observed for the regulatory domain. PKCalpha, but not PKCalpha regulatory domain expression stimulates migration on beta1 integrin substrates. This PKCalpha-enhanced migratory response is inhibited by blockade of endocytosis.

  • Keywords:

    • endocytosis,
    • FRET,
    • GFP,
    • integrin,
    • migration,
    • protein kinase C