The Exocyst Protein Exo70, but not Sec6, is Recruited to Listeria Protrusions During Cell‐to‐Cell Spreading

Abstract

Listeria monocytogenes bacteria kill ~25 % of people that they infect. This extends to a mortality rate of ~30% of infected unborn foetuses. Crucial to Listeria's infections are it's ability to move from one cell to its neighboring cells in order to infect entire organ systems while remaining undetectable to the immune system. It does this by hijacking the host cell's actin cytoskeleton, generating actin‐rich structures called comet tails and interacting with the host cell's plasma membrane forming bacterial protrusions referred to as listeriopods to push into their adjacent cells. The exocyst complex of proteins is used by cells to exocytose vesicles. This protein complex utilizes the proteins Exo70, Sec6 as well as six others to accomplish this task. Exo70 is a multifunctional protein that can engage with the actin cytoskeleton to promote branched actin filament formation through interactions with the Arp2/3 complex. To examine whether exocyst components are involved in the cell‐to‐cell spreading of Listeria we examined Exo70 and Sec6 localization. GFP‐Exo70 accumulated at the tip and along the length of growing listeriopods during live cell microscopy, while Sec6, was not found at elevated levels at the Listeria protrusions. This work suggests that Exo70 is independent of the exocyst complex and is recruited to listeriopods.Support or Funding InformationFunding provided through NSERC. (Grant No. 355316 to J. A. G.)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.