Calcium-stimulated disassembly of focal adhesions mediated by an ORP3/IQSec1 complex

R. S. D'Souza, J. Y. Lim, A. Turgut, K. Servage, J. Zhang, K. Orth, N. G. Sosale, M. J. Lazzara, J. C. Allegood, J. E. Casanova

Research output: Contribution to journalArticlepeer-review


Coordinated assembly and disassembly of integrin-mediated focal adhesions (FAs) is essential for cell migration. Many studies have shown that FA disassembly requires Ca2+ influx, however our understanding of this process remains incomplete. Here we show that Ca2+ influx via STIM1/Orai1 calcium channels, which cluster near FAs, leads to activation of the GTPase Arf5 via the Ca2+-activated GEF IQSec1, and that both IQSec1 and Arf5 activation are essential for adhesion disassembly. We further show that IQSec1 forms a complex with the lipid transfer protein ORP3, and that Ca2+ influx triggers PKC-dependent translocation of this complex to ER/plasma membrane contact sites adjacent to FAs. In addition to allosterically activating IQSec1, ORP3 also extracts PI4P from the PM, in exchange for phosphatidylcholine. ORP3-mediated lipid exchange is also important for FA turnover. Together, these findings identify a new pathway that links calcium influx to FA turnover during cell migration.

Original languageEnglish (US)
JournalUnknown Journal
StatePublished - Dec 5 2019

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • Immunology and Microbiology(all)
  • Neuroscience(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Fingerprint Dive into the research topics of 'Calcium-stimulated disassembly of focal adhesions mediated by an ORP3/IQSec1 complex'. Together they form a unique fingerprint.

Cite this