title: Effects of retroviral envelope-protein cleavage upon trafficking, incorporation, and membrane fusion.
abstract: Retroviral envelope glycoproteins undergo proteolytic processing by cellular subtilisin-like proprotein convertases at a polybasic amino-acid site in order to produce the two functional subunits, SU and TM. Most previous studies have indicated that envelope-protein cleavage is required for rendering the protein competent for promoting membrane fusion and for virus infectivity. We have investigated the role of proteolytic processing of the Moloney murine leukemia virus envelope-protein through site-directed mutagenesis of the residues near the SU-TM cleavage site and have established that uncleaved glycoprotein is unable either to be incorporated into virus particles efficiently or to induce membrane fusion. Additionally, the results suggest that cleavage of the envelope protein plays an important role in intracellular trafficking of protein via the cellular secretory pathway. Based on our results it was concluded that a positively charged residue located at either P2 or P4 along with the arginine at P1 is essential for cleavage.
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392, USA. apte@purdue.edu
authors.forename: Swapna
authors.initials: S
authors.lastname: Apte
authors.forename: David Avram
authors.initials: DA
authors.lastname: Sanders
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D006801:Humans; D051379:Mice; D008979:Moloney murine leukemia virus / Q000502:physiology*; D009154:Mutation; D041681:NIH 3T3 Cells; D021381:Protein Transport; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D053585:Virus Attachment; D053586:Virus Internalization
chemical_list: D014759:Viral Envelope Proteins