title: Mutations in the rotavirus spike protein VP4 reduce trypsin sensitivity but not viral spread.
abstract: Infectious entry of the nonenveloped rotavirus virion requires proteolysis of the spike protein VP4 to mediate conformational changes associated with membrane penetration. We sequenced and characterized an isolate that was cultured in the absence of trypsin and found that it is more resistant to proteolysis than WT virus. A substitution mutation abrogates one of the defined trypsin-cleavage sites, suggesting that blocking proteolysis at this site reduces the overall kinetics of proteolysis. Kinetic analysis of the membrane penetration-associated conformational change indicated that the 'fold-back' of the mutant spike protein is slower than that of WT. Despite these apparent biochemical defects, the mutant virus replicates in an identical manner to the WT virus. These findings enhance an understanding of VP4 functions and establish new strategies to interrogate rotavirus cell entry.
authors: Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-8026, USA.
authors: Shane D
authors: SD
authors: Trask
authors: Department of Pediatrics and the Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2581, USA.
authors: J Denise
authors: JD
authors: Wetzel
authors: Departments of Pediatrics and Pathology, Microbiology and Immunology and the Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2581, USA.
authors: Terence S
authors: TS
authors: Dermody
authors: Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-8026, USA.
authors: John T
authors: JT
authors: Patton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D036022:Capsid Proteins / Q000235:genetics* / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006801:Humans; D008253:Macaca mulatta; D008969:Molecular Sequence Data; D009154:Mutation; D011499:Protein Processing, Post-Translational; D012401:Rotavirus / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D012400:Rotavirus Infections / Q000201:enzymology* / Q000821:virology*; D016415:Sequence Alignment; D014357:Trypsin / Q000378:metabolism*; D053586:Virus Internalization; D014779:Virus Replication
chemical_list: D036022:Capsid Proteins; C060339:VP4 protein, Rotavirus; D014357:Trypsin