Human papillomavirus E5 oncoproteins bind the A4 endoplasmic reticulum protein to regulate proliferative ability upon differentiation

Katarina Kotnik Halavaty, Jennifer Regan, Kavi Mehta, Laimonis Laimins*

*Corresponding author for this work

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Human papillomaviruses (HPV) infect stratified epithelia and link their life cycles to epithelial differentiation. The HPV E5 protein plays a role in the productive phase of the HPV life cycle but its mechanism of action is still unclear. We identify a new binding partner of E5, A4, using a membrane-associated yeast-two hybrid system. The A4 protein co-localizes with HPV 31 E5 in perinuclear regions and forms complexes with E5 and Bap31. In normal keratinocytes, A4 is found primarily in basal cells while in HPV positive cells high levels of A4 are seen in both undifferentiated and differentiated cells. Reduction of A4 expression by shRNAs, enhanced HPV genome amplification and increased cell proliferation ability following differentiation but this was not seen in cells lacking E5. Our studies suggest that the A4 protein is an important E5 binding partner that plays a role in regulating cell proliferation ability upon differentiation.

Original languageEnglish (US)
Pages (from-to)223-230
Number of pages8
JournalVirology
Volume452-453
DOIs
StatePublished - Mar 2014

Keywords

  • Amplification
  • Differentiation
  • Endoplasm
  • Keratinocyte

ASJC Scopus subject areas

  • Virology

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