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Title: The polyomavirus BK agnoprotein co-localizes with lipid droplets

Agnoprotein encoded by human polyomavirus BK (BKV) is a late cytoplasmic protein of 66 amino acids (aa) of unknown function. Immunofluorescence microscopy revealed a fine granular and a vesicular distribution in donut-like structures. Using BKV(Dunlop)-infected or agnoprotein-transfected cells, we investigated agnoprotein co-localization with subcellular structures. We found that agnoprotein co-localizes with lipid droplets (LD) in primary human renal tubular epithelial cells as well as in other cells supporting BKV replication in vitro (UTA, Vero cells). Using agnoprotein-enhanced green fluorescent protein (EGFP) fusion constructs, we demonstrate that agnoprotein aa 20-42 are required for targeting LD, whereas aa 1-20 or aa 42-66 were not. Agnoprotein aa 22-40 are predicted to form an amphipathic helix, and mutations A25D and F39E, disrupting its hydrophobic domain, prevented LD targeting. However, changing the phosphorylation site serine-11 to alanine or aspartic acid did not alter LD co-localization. Our findings provide new clues to unravel agnoprotein function.
Authors:
; ;  [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Transplantation Virology, Institute for Medical Microbiology, Department of Biomedicine, University of Basel, CH-4003 Basel (Switzerland)
  2. Bio-Optics Facility, Department of Biomedicine, University of Basel, Basel (Switzerland)
  3. Department of Microbiology and Infection Control, University Hospital of North Norway, Tromso (Norway)
  4. (Switzerland)
Publication Date:
OSTI Identifier:
21357607
Resource Type:
Journal Article
Resource Relation:
Journal Name: Virology; Journal Volume: 399; Journal Issue: 2; Other Information: DOI: 10.1016/j.virol.2010.01.011; PII: S0042-6822(10)00028-0; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ALANINES; ASPARTIC ACID; DROPLETS; KIDNEYS; LIPIDS; MUTATIONS; PHOSPHORYLATION; PROTEINS; SERINE; VIRUSES AMINO ACIDS; BODY; CARBOXYLIC ACIDS; CHEMICAL REACTIONS; HYDROXY ACIDS; MICROORGANISMS; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANS; PARASITES; PARTICLES