Regulation of membrane ruffling by polarized STIM1 and ORAI1 in cortactin-rich domains

Sci Rep. 2017 Mar 24;7(1):383. doi: 10.1038/s41598-017-00331-4.

Abstract

Cell motility and migration requires the reorganization of the cortical cytoskeleton at the leading edge of cells and extracellular Ca2+ entry is essential for this reorganization. However the molecular nature of the regulators of this pathway is unknown. This work contributes to understanding the role of STIM1 and ORAI1 in the promotion of membrane ruffling by showing that phospho-STIM1 localizes at the leading edge of cells, and that both phospho-STIM1 and ORAI1 co-localize with cortactin (CTTN), a regulator of the cytoskeleton at membrane ruffling areas. STIM1-KO and ORAI1-KO cell lines were generated by CRISPR/Cas9 genome editing in U2OS cells. In both cases, KO cells presented a notable reduction of store-operated Ca2+ entry (SOCE) that was rescued by expression of STIM1-mCherry and ORAI1-mCherry. These results demonstrated that SOCE regulates membrane ruffling at the leading edge of cells. Moreover, endogenous ORAI1 and overexpressed ORAI1-GFP co-immunoprecipitated with endogenous CTTN. This latter result, in addition to the KO cells' phenotype, the preservation of ORAI1-CTTN co-localization during ruffling, and the inhibition of membrane ruffling by the Ca2+-channel inhibitor SKF96365, further supports a functional link between SOCE and membrane ruffling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Signaling*
  • Cell Line
  • Cell Membrane / metabolism*
  • Cell Movement*
  • Cortactin / metabolism*
  • Humans
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / metabolism
  • Mice
  • Neoplasm Proteins / metabolism*
  • ORAI1 Protein / metabolism*
  • Stromal Interaction Molecule 1 / metabolism*

Substances

  • Cortactin
  • Cttn protein, mouse
  • Neoplasm Proteins
  • ORAI1 Protein
  • ORAI1 protein, human
  • Orai1 protein, mouse
  • STIM1 protein, human
  • Stim1 protein, mouse
  • Stromal Interaction Molecule 1