Listeria and Interaction with ActA and Arp 23

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Listeria and Interaction with ActA and Arp 2/3

• Dan Eidman
• Staples High School
• Westport, CT

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• Better Late Than Never

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Interaction of Human Arp2/3 Complex and the
LIsteria monocytogenes ActA Protein in Actin
Filament Nucleation

• Matthew D. Welch et. al.
• Science. Vol 281. pp 105-108

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• Better Late Than Never

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Introduction

• Listeria monocytogenes is a pathogenic bacterium
• Actin filament polymerization
• Motility within cell
• ActA
• Arp 2/3

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Purpose

• Study in detail ActA and the Arp2/3 complex in
  order to learn more about their characteristics

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Arp2/3 in Listeria monocytogenes

• Srtuctural models of Arp 2 and Arp 3 suggest
  actin assembly
• G-actin
• May also recruit actin filaments
• F-actin
• Actin clouds were observed with bacteria

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Results (Arp 2/3 in L. monocytogenes)
Bacteria
Actin Clouds
G-Actin
F-Actin
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Arp2/3 and ActA without Bacteria

• Arp 2/3 accelerated polymerization compared to
  Actin alone
• ActA did not change polymerization
• ActA and Arp2/3 together
• Function together very efficiently to accelerate
  polymerization

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ActA and Arp2/3
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Discussion

• Arp2/3 only mildly increases polymerization on
  its own
• ActA works with Arp 2/3 to stimulate rapid
  polymerization
• This can be used to regulate motility

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So What Does This All Mean?

• Arp2/3 and ActA can be used for motility in
  nanomachines
• Navigate through human body
• One step closer to nanomedicine