Abstract
Budding of C-type retroviruses begins when the viral Gag polyprotein is directed to the plasma membrane by an N-terminal membrane-binding (M) domain. While dispersed basic amino acids within the M domain are critical for stable membrane association and consequent particle assembly, additional residues or motifs may be required for specific plasma membrane targeting and binding. We have identified an assembly-defective Rous sarcoma virus (RSV) Gag mutant that retains significant membrane affinity despite having a deletion of the fourth alpha-helix of the M domain. Examination of the mutant protein's subcellular distribution revealed that it was not localized to the plasma membrane but instead was mistargeted to intracytoplasmic membranes. Specific plasma membrane targeting was restored by the addition of myristate plus a single basic residue, by multiple basic residues, or by the heterologous hydrophobic membrane-binding domain from the cellular Fyn protein. These results suggest that the fourth alpha-helix of the RSV M domain promotes specific targeting of Gag to the plasma membrane, either through a direct interaction with plasma membrane phospholipids or a membrane-associated cellular factor or by maintaining the conformation of Gag to expose specific plasma membrane targeting sequences.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.