Solubilization of Human Cells by the Styrene-Maleic Acid Copolymer: Insights From Fluorescence Microscopy

Biochim Biophys Acta Biomembr. 2017 Nov;1859(11):2155-2160. doi: 10.1016/j.bbamem.2017.08.010. Epub 2017 Aug 25.


Extracting membrane proteins from biological membranes by styrene-maleic acid copolymers (SMAs) in the form of nanodiscs has developed into a powerful tool in membrane research. However, the mode of action of membrane (protein) solubilization in a cellular context is still poorly understood and potential specificity for cellular compartments has not been investigated. Here, we use fluorescence microscopy to visualize the process of SMA solubilization of human cells, exemplified by the immortalized human HeLa cell line. Using fluorescent protein fusion constructs that mark distinct subcellular compartments, we found that SMA solubilizes membranes in a concentration-dependent multi-stage process. While all major intracellular compartments were affected without a strong preference, plasma membrane solubilization was found to be generally slower than the solubilization of organelle membranes. Interestingly, some plasma membrane-localized proteins were more resistant against solubilization than others, which might be explained by their presence in specific membrane domains with differing properties. Our results support the general applicability of SMA for the isolation of membrane proteins from different types of (sub)cellular membranes.

Keywords: Cellular localization; Membrane domain; Native nanodiscs; Plasma membrane organization; Preferential solubilization; SMA-resistant membranes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Fractionation / methods*
  • Cell Membrane / chemistry
  • Cell Membrane / drug effects
  • Cell Membrane / ultrastructure
  • HeLa Cells
  • Humans
  • Lipid Bilayers
  • Maleates / chemistry
  • Maleates / pharmacology*
  • Microscopy, Fluorescence
  • Polymers / chemistry
  • Polymers / pharmacology*
  • Polystyrenes / chemistry
  • Solubility
  • Styrene / chemistry
  • Styrene / pharmacology*
  • Subcellular Fractions* / chemistry
  • Subcellular Fractions* / drug effects
  • Subcellular Fractions* / ultrastructure


  • Lipid Bilayers
  • Maleates
  • Polymers
  • Polystyrenes
  • Styrene
  • styrofoam
  • maleic acid