Nanoscale Landscape of Phosphoinositides Revealed by the Specific PH-domains Using Single-molecule Super-resolution Imaging in the Plasma Membrane [Cell Biology]

September 22nd, 2015 by Ji, C., Zhang, Y., Xu, P., Xu, T., Lou, X.

Both PI4P and PI(4,5)P2 are independent plasma membrane (PM) determinant lipids that are essential for multiple cellular functions. However, their nano-scale spatial organization in the PM remains elusive. Using single-molecule super-resolution microscopy and new photoactivatable fluorescence probes based on the PH-domains that specifically recognize phosphatidylinositides in insulin-secreting INS-1 cells, we reported that the PI(4,5)P2 probes exhibited a remarkably uniform distribution in the major regions of the PM, with some sparse PI(4,5)P2 enriched membrane patches/domains of diverse sizes (383 ± 14 nm in average). Quantitative analysis revealed a modest concentration gradient which was much less steep than previously thought, and no densely packed PI(4,5)P2 nano-domains were observed. Live-cell super-resolution imaging further demonstrated the dynamic structural changes of those domains in the flat PM and membrane protrusions. PI4P and PI(3,4,5)P3 showed the similar spatial distributions as PI(4,5)P2. These data reveal the nanoscale landscape of key inositol phospholipids in the native PM and imply a framework for local cellular signaling and lipid-protein interactions at nanometer scale.
  • Posted in Journal of Biological Chemistry, Publications
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