A class of integral membrane proteins, referred to as Mistic polypeptides, their variants, fusion proteins including a Mistic polypeptide domain, and nucleic acid molecules encoding Mistic polypeptides and Mistic fusion proteins are disclosed herein. Also described are methods of using Mistic polypeptides and Mistic fusion proteins to produce and/or isolate recombinant proteins (including without limitation classes of eukaryotic proteins that have previously been intractable to recombinant bacterial expression, such as, eukaryotic integral membrane proteins).