Final answer:
Listeria monocytogenes expresses a bacterial surface protein called ActA that indirectly recruits the Arp2/3 complex to nucleate actin polymerization.
Step-by-step explanation:
Listeria monocytogenes, a facultative intracellular pathogen, is the pathogen that expresses a bacterial surface protein that indirectly recruits the Arp2/3 complex to nucleate actin polymerization. This surface protein is known as actin assembly-inducing protein (ActA) and it is expressed on the surface of Listeria. ActA binds to the Arp2/3 complex, which then nucleates actin polymerization, enabling the bacterium to produce actin tails and move within the host cell.