Legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activity

Abstract The bacterial pathogen Legionella pneumophila delivers more than 330 effector proteins into host cells through its Dot/Icm type IV secretion system (T4SS) to facilitate its intracellular replication. A number of these effectors modulate organelle trafficking pathways to create a membrane‐bo...

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Main Authors: Yan Liu, Yao Liu, Zhao‐Qing Luo
Format: Article
Language:English
Published: Wiley 2025-06-01
Series:mLife
Subjects:
Online Access:https://doi.org/10.1002/mlf2.70013
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author Yan Liu
Yao Liu
Zhao‐Qing Luo
author_facet Yan Liu
Yao Liu
Zhao‐Qing Luo
author_sort Yan Liu
collection DOAJ
description Abstract The bacterial pathogen Legionella pneumophila delivers more than 330 effector proteins into host cells through its Dot/Icm type IV secretion system (T4SS) to facilitate its intracellular replication. A number of these effectors modulate organelle trafficking pathways to create a membrane‐bound niche called the Legionella‐containing vacuole (LCV). In this study, we found that L. pneumophila induces F‐actin accumulation in the host cell cortex by its Dot/Icm substrate RavJ (Lpg0944). RavJ harbors a C101H138D170 motif associated with human tissue transglutaminases (TGs). We show that RavJ catalyzes a covalent linkage between actin and members of the Motin family of proteins, including Angiomotin (AMOT) and Angiomotin‐like 1 (AMOTL1), which are known to regulate cell migration and contribute to the formation of cellular structures such as endothelial cell junctions and tubes. Further study reveals that RavJ‐induced crosslink between actin and AMOT occurs on its Gln354 residue. Crosslink between actin and AMOT significantly reduces the binding between actin and its binding partner cofilin, suggesting that RavJ inhibits actin depolymerization. We also demonstrate that the metaeffector LegL1 directly interacts with RavJ to antagonize its TG activity, leading to reduced crosslinks between actin and Motin proteins. Our results reveal a novel mechanism of modulating the host actin cytoskeleton by L. pneumophila.
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spelling doaj-art-4d5d103daf2d49c7aa216acc02b26c1f2025-08-20T02:37:46ZengWileymLife2770-100X2025-06-014323224810.1002/mlf2.70013Legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activityYan Liu0Yao Liu1Zhao‐Qing Luo2Department of Biological Sciences, Purdue Institute for Inflammation, Immunology and Infectious Diseases Purdue University West Lafayette Indiana USADepartment of Biological Sciences, Purdue Institute for Inflammation, Immunology and Infectious Diseases Purdue University West Lafayette Indiana USADepartment of Biological Sciences, Purdue Institute for Inflammation, Immunology and Infectious Diseases Purdue University West Lafayette Indiana USAAbstract The bacterial pathogen Legionella pneumophila delivers more than 330 effector proteins into host cells through its Dot/Icm type IV secretion system (T4SS) to facilitate its intracellular replication. A number of these effectors modulate organelle trafficking pathways to create a membrane‐bound niche called the Legionella‐containing vacuole (LCV). In this study, we found that L. pneumophila induces F‐actin accumulation in the host cell cortex by its Dot/Icm substrate RavJ (Lpg0944). RavJ harbors a C101H138D170 motif associated with human tissue transglutaminases (TGs). We show that RavJ catalyzes a covalent linkage between actin and members of the Motin family of proteins, including Angiomotin (AMOT) and Angiomotin‐like 1 (AMOTL1), which are known to regulate cell migration and contribute to the formation of cellular structures such as endothelial cell junctions and tubes. Further study reveals that RavJ‐induced crosslink between actin and AMOT occurs on its Gln354 residue. Crosslink between actin and AMOT significantly reduces the binding between actin and its binding partner cofilin, suggesting that RavJ inhibits actin depolymerization. We also demonstrate that the metaeffector LegL1 directly interacts with RavJ to antagonize its TG activity, leading to reduced crosslinks between actin and Motin proteins. Our results reveal a novel mechanism of modulating the host actin cytoskeleton by L. pneumophila.https://doi.org/10.1002/mlf2.70013Dot/Icm type IV secretion systemLegionella pneumophilametaeffector LegL1transglutaminase activity
spellingShingle Yan Liu
Yao Liu
Zhao‐Qing Luo
Legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activity
mLife
Dot/Icm type IV secretion system
Legionella pneumophila
metaeffector LegL1
transglutaminase activity
title Legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activity
title_full Legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activity
title_fullStr Legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activity
title_full_unstemmed Legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activity
title_short Legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activity
title_sort legionella pneumophila modulates the host cytoskeleton by an effector of transglutaminase activity
topic Dot/Icm type IV secretion system
Legionella pneumophila
metaeffector LegL1
transglutaminase activity
url https://doi.org/10.1002/mlf2.70013
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AT yaoliu legionellapneumophilamodulatesthehostcytoskeletonbyaneffectoroftransglutaminaseactivity
AT zhaoqingluo legionellapneumophilamodulatesthehostcytoskeletonbyaneffectoroftransglutaminaseactivity