Membrane proteins vary from highly hydrophilic to predominately hydrophobic.
Some membrane proteins are modified. Thickness of lipid bilayer can vary. In addition, some membrane lipid can be in a nonbilayer configuration, such as some of the lipid directly associated with an integral membrane protein. Membrane proteins can form dimers or larger aggregates. An example of unique protein localization in a membrane is the location of viral envelope proteins in a portion of a membrane which does not contain any host cell membrane proteins.