Toxoplasma effector TgWIP hijacks dendritic cell actin and motility via Nck1/Grb2 and the WAVE complex.

The intracellular parasite Toxoplasma gondii enhances its dissemination to distant organs by hijacking infected leukocytes via a Trojan Horse mechanism. Upon infecting dendritic cells (DCs), Toxoplasma induces a hypermigratory phenotype characterized by podosome dissolution and formation of F-actin stress fibers. We previously showed that these cytoskeletal changes depend on the effector protein Toxoplasma WAVE complex-interacting protein (TgWIP) secreted from parasites to infected leukocytes. Here, we identify the host adaptor proteins non-catalytic region of tyrosine kinase adaptor protein 1 and 2 (Nck1/2) and growth factor receptor-bound protein 2 (Grb2) as direct TgWIP interactors. TgWIP mainly uses two distinct proline-rich regions (PRRs) to interact with Nck1 and Grb2. Mutating these PRRs abrogates TgWIP binding to Nck1 and Grb2 and diminishes podosome dissolution and DC hypermotility. Furthermore, we show that TgWIP directly interacts with the actin nucleation-promoting factor WAVE regulatory complex (WRC) via a WRC-interacting receptor sequence (WIRS). Disrupting this interaction also influences actin cytoskeletal remodeling and DC hypermotility. Collectively, our data reveal that TgWIP directly interacts with multiple actin regulators, including Nck1, Grb2, and the WRC, to remodel the actin cytoskeleton of the host cells, elucidating a key mechanism that Toxoplasma exploits to enhance host cell migration and dissemination.IMPORTANCEThe parasite Toxoplasma gondii spreads throughout the body by hijacking immune cells and boosting their motility. This ability depends on secreted parasite proteins that manipulate the host cell's actin cytoskeleton. One such effector, Toxoplasma gondii WAVE-interacting protein (TgWIP), induces dramatic changes in host cell shape and movement, but how it does this has remained unclear. Here, we show that TgWIP directly interacts with multiple host actin-regulatory proteins using distinct sequence motifs. Disrupting these interactions prevents cytoskeletal remodeling and impairs parasite-induced immune cell migration. Our study reveals that Toxoplasma uses defined motifs to co-opt host signaling hubs that control cell motility. Understanding how pathogens exploit the cytoskeleton not only sheds light on host-pathogen interactions but may also reveal broader principles of cell migration relevant to immunity, cancer, and development.