title: Nanoscale Landscape of Phosphoinositides Revealed by Specific Pleckstrin Homology (PH) Domains Using Single-molecule Superresolution Imaging in the Plasma Membrane.
abstract: Both phosphatidylinositol 4-phosphate (PI4P) and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) are independent plasma membrane (PM) determinant lipids that are essential for multiple cellular functions. However, their nanoscale spatial organization in the PM remains elusive. Using single-molecule superresolution microscopy and new photoactivatable fluorescence probes on the basis of pleckstrin homology domains that specifically recognize phosphatidylinositides in insulin-secreting INS-1 cells, we report 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 on average). Quantitative analysis revealed a modest concentration gradient that was much less steep than previously thought, and no densely packed PI(4,5)P2 nanodomains were observed. Live-cell superresolution imaging further demonstrated the dynamic structural changes of those domains in the flat PM and membrane protrusions. PI4P and phosphatidylinositol (3,4,5)-trisphosphate (PI(3,4,5)P3) showed 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 a nanometer scale.
authors.affiliation: Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53705 and.
authors.forename: Chen
authors.initials: C
authors.lastname: Ji
authors.affiliation: the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yongdeng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Pingyong
authors.initials: P
authors.lastname: Xu
authors.affiliation: the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
authors.affiliation: Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53705 and. Electronic address: xlou3@wisc.edu.
authors.forename: Xuelin
authors.initials: X
authors.lastname: Lou
mesh_terms: D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002522:Chlorocebus aethiops; D050417:Insulin-Secreting Cells / Q000378:metabolism / Q000648:ultrastructure; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D036103:Nanotechnology; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051381:Rats; D015398:Signal Transduction; D050827:Syntaxin 1 / Q000378:metabolism
chemical_list: D008164:Luminescent Proteins; D008565:Membrane Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C494213:Stx1a protein, rat; D050827:Syntaxin 1; C060974:phosphatidylinositol 3,4,5-triphosphate; C037178:phosphatidylinositol 4-phosphate
keywords: SNARE proteins; inositol phospholipid; membrane lipid; metabolism; phosphatidylinositol; superresolution microscopy; β cell (B cell)