Characterization of the Herpes Simplex Virus 1 VP11/12-tyrosine based binding motifs for Src family kinases, p85, Grb2 and Shc

• Author / Creator

  Strunk, Ulrike

• Infection with HSV-1 triggers several events specifically designed to manipulate cell signal transduction pathways. Two major signaling cascades targeted by the virus are the PI3K/Akt-pathway and the TCR-signaling pathway. Prior to the studies presented in this thesis, it was known that the tegument protein VP11/12 associates with cellular proteins that are directly involved in those pathways. Specially, it was suggested that VP11/12 associates with SFKs, p85, Grb2 and Shc through specific tyrosine-based binding motifs that are located within the C-terminal region of VP11/12. Here, we first generated point-mutated viruses with inactive binding motifs and assessed the ability of mutant VP11/12 to associate with the SFKs, p85, Grb2 and Shc. I found that inactivation of the predicted binding motifs for SFKs, Grb2 and Shc eliminated the protein-VP11/12 associations. In the case of p85, I was able to demonstrate that inactivation of the predicted p85-binding motif significantly reduced, but did not eliminate, the VP11/12-p85 interaction. From these results, it became evident that VP11/12 requires the phosphorylation of specific tyrosine-based binding motifs within its C-terminal region in order to associate with SFKs, p85, Grb2 and Shc. Next, I determined the downstream effects of eliminating these protein-protein associations. I provide data suggesting that VP11/12 requires the recruitment and activation of SFKs to further associate with Grb2, Shc and p85 as well as to induce global phosphorylation of VP11/12. Further, I was able to demonstrate that VP11/12 must associate with SFKs, Grb2 and p85 in order to activate Akt during infection. In addition, I provide data suggesting that VP11/12 needs to associate with SFKs in order to severely reduce TCR signaling events upon transfection. Taken together, this data fully supports the Wagner-Smiley model demonstrating that VP11/12 mimics an activated receptor in that VP11/12 associates with cellular proteins that are directly involved in the stimulation of the PI3K/Akt- as well as the TCR-signaling pathways.

• Subjects / Keywords

  • PI3K/Akt-pathway
  • Tyrosine based binding motifs
  • HSV-1
  • VP11/12
  • TCR-pathway

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3N010835

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.