One, two or three? Probing the stoichiometry of membrane proteins by single-molecule localization microscopy

Sci Rep. 2015 Sep 11;5:14072. doi: 10.1038/srep14072.

Abstract

Probing the oligomeric state of abundant molecules, such as membrane proteins in intact cells, is essential, but has not been straightforward. We address this challenge with a simple counting strategy that is capable of reporting the oligomeric state of dense, membrane-bound protein complexes. It is based on single-molecule localization microscopy to super-resolve protein structures in intact cells and basic quantitative evaluation. We validate our method with membrane-bound monomeric CD86 and dimeric cytotoxic T-lymphocyte-associated protein as model proteins and confirm their oligomeric states. We further detect oligomerization of CD80 and vesicular stomatitis virus glycoprotein and propose coexistence of monomers and dimers for CD80 and trimeric assembly of the viral protein at the cell membrane. This approach should prove valuable for researchers striving for reliable molecular counting in cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • B7-1 Antigen / chemistry
  • B7-1 Antigen / metabolism
  • Flow Cytometry
  • Humans
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Microscopy / methods*
  • Models, Theoretical*
  • Protein Multimerization
  • Reproducibility of Results
  • Viral Proteins / chemistry
  • Viral Proteins / metabolism

Substances

  • B7-1 Antigen
  • Membrane Proteins
  • Viral Proteins