Carcinoembryonic antigen-related cellular adhesion molecules (CEACAMs)
are involved in intercellular interactions that control cellular growth,
differentiation, transformation, tumourigenesis, inflammation and infection.
Previous studies of the CEACAM family have provided compelling evidence
for the existence of a complex equilibrium of monomers and dimers(or
oligomers) and have identified key factors that appear to influence the
equilibrium. To date, how CEACAMs behave, interact, organize and self
associate at the cell membrane remains poorly understood. We have
previously demonstrated using live cell TIRF-homoFRET imaging that a
heterogeneous population of CEACAM1 monomers and oligomers exist
throughout the cell membrane but that the population was skewed towards
the monomeric form in actin-rich domains. However these homo-FRET maps
are diffraction-limited and do not represent the true spatial distribution or
dynamics of CEACAM1. In order to address these questions, we have applied
direct stochastic optical reconstruction microscopy (dSTORM), a super
resolution optical microscopy technique, to directly map the structure,
distribution and oligomeric states of CEACAM1 with ~ 20 nm spatial resolution.
This powerful approach will enable us to elucidate the spatial distribution of
CEACAM1, and aid in identifying correlations between CEACAM1 self
association, molecular structure, and function.