Merkel cell polyomavirus large T antigen disrupts lysosome clustering by translocating human Vam6p from the cytoplasm to the nucleus

J Biol Chem. 2011 May 13;286(19):17079-90. doi: 10.1074/jbc.M110.192856. Epub 2011 Mar 16.

Abstract

Merkel cell polyomavirus (MCV) has been recently described as the cause for most human Merkel cell carcinomas. MCV is similar to simian virus 40 (SV40) and encodes a nuclear large T (LT) oncoprotein that is usually mutated to eliminate viral replication among tumor-derived MCV. We identified the hVam6p cytoplasmic protein involved in lysosomal processing as a novel interactor with MCV LT but not SV40 LT. hVam6p binds through its clathrin heavy chain homology domain to a unique region of MCV LT adjacent to the retinoblastoma binding site. MCV LT translocates hVam6p to the nucleus, sequestering it from involvement in lysosomal trafficking. A naturally occurring, tumor-derived mutant LT (MCV350) lacking a nuclear localization signal binds hVam6p but fails to inhibit hVam6p-induced lysosomal clustering. MCV has evolved a novel mechanism to target hVam6p that may contribute to viral uncoating or egress through lysosomal processing during virus replication.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Antigens, Polyomavirus Transforming / chemistry*
  • Autophagy-Related Proteins
  • Cell Line, Tumor
  • Cell Nucleus / metabolism*
  • Cytoplasm / metabolism*
  • Exocytosis
  • Humans
  • Intracellular Signaling Peptides and Proteins / chemistry
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Lysosomes / metabolism*
  • Mass Spectrometry
  • Merkel Cells / virology*
  • Models, Biological
  • Protein Binding
  • Protein Transport
  • Retinoblastoma Protein / metabolism
  • Transfection
  • Vesicular Transport Proteins / chemistry
  • Vesicular Transport Proteins / metabolism*
  • Virus Replication

Substances

  • Antigens, Polyomavirus Transforming
  • Autophagy-Related Proteins
  • Intracellular Signaling Peptides and Proteins
  • Retinoblastoma Protein
  • VPS39 protein, human
  • Vesicular Transport Proteins