With the recent success in recording mass spectra of membrane protein complexes, many surprising properties of these gas phase complexes have come to the fore.Among them is the survival of interactions between membrane and soluble subunits in vacuum;the high hydrophobicity did not preclude ionization however leading to low charge state observed.Another unexpected finding is that these gas phase membrane complexes carry with them endogeneous lipids, bound specifically in subunit interfaces.This provides us with an opportunity to distinguish annular lipids from structural lipids that have a role in maintaining structure and subunit interactions, and leads to a growing realization that, to understand the function of membrane complexes, it is not only the structures of the protein components that are important but also knowledge of the protein-lipid interactions.Furthermore, structural dynamics crucial for the in vivo function and regulation of these complexes are mirrored from their characteristic behavior by ion mobility mass spectrometry analysis.Here we use several examples to illustrate these properties and highlight the potential of mass spectrometry in the study of membrane-embedded assemblies.