Cell surface display of a protein based on a tail-anchored membrane protein

Abstract

Methods for displaying proteins on the cell surface are widely used in protein-based biotechnology and bioengineering, where target proteins are expressed as fusion constructs with membrane proteins through recombinant DNA technology. In this study, we developed a system for displaying a protein on the cell surface using the transmembrane domain (TMD) of a tail-anchored membrane protein (TA protein). TA proteins have an orientation in the cell membrane such that their C-termini are displayed on the cell surface, which contrasts with that of type I transmembrane proteins that are commonly used as anchoring units. Therefore, by utilizing the TMD of a TA protein as an anchoring unit, desired proteins can be attached to the TMD via their N-termini. This approach is advantageous for displaying proteins whose C-terminal regions play important roles in their activity. In this study, we chose the inner nuclear membrane protein emerin as a TA protein and constructed expression systems in mammalian cells for a series of fusion proteins based on deleted forms of emerin. We found that utilizing emerin that lacks 210 residues from the N-terminus as a TMD allowed efficient translocation of the fusion protein to the plasma membrane, successfully displaying its target protein portion on the cell surface. Thus, our system serves as an effective method for protein display, enhancing the applicability of cell surface display technology based on transmembrane proteins.