The TLR4 adaptor TRAM controls the phagocytosis of Gram-negative bacteria by interacting with the Rab11-family interacting protein 2

Astrid Skjesol; Mariia Yurchenko; Korbinian Bösl; Caroline Gravastrand; Kaja Elisabeth Nilsen; Lene Melsæther Grøvdal; Federica Agliano; Francesco Patane; Germana Lentini; Hera Kim; Giuseppe Teti; Aditya Kumar Sharma; Richard K Kandasamy; Bjørnar Sporsheim; Kristian K Starheim; Douglas T Golenbock; Harald Stenmark; Mary McCaffrey; Terje Espevik; Harald Husebye

doi:10.1371/journal.ppat.1007684

The TLR4 adaptor TRAM controls the phagocytosis of Gram-negative bacteria by interacting with the Rab11-family interacting protein 2

PLoS Pathog. 2019 Mar 18;15(3):e1007684. doi: 10.1371/journal.ppat.1007684. eCollection 2019 Mar.

Authors

Astrid Skjesol¹, Mariia Yurchenko¹, Korbinian Bösl¹, Caroline Gravastrand¹, Kaja Elisabeth Nilsen¹, Lene Melsæther Grøvdal¹, Federica Agliano^{1

2}, Francesco Patane^{1

2}, Germana Lentini^{1

2}, Hera Kim¹, Giuseppe Teti², Aditya Kumar Sharma¹, Richard K Kandasamy¹, Bjørnar Sporsheim¹, Kristian K Starheim¹, Douglas T Golenbock³, Harald Stenmark^{1

4

5}, Mary McCaffrey⁶, Terje Espevik^{1

7}, Harald Husebye^{1

7}

Affiliations

¹ Centre of Molecular Inflammation Research, Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
² Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy.
³ Program in Innate Immunity, Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America.
⁴ Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway.
⁵ Department for Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo Norway.
⁶ Molecular Cell Biology Laboratory, Biochemistry Department, Biosciences Institute, University College Cork, Cork, Ireland.
⁷ The Central Norway Regional Health Authority, St. Olavs Hospital HF, Trondheim, Norway.

Abstract

Phagocytosis is a complex process that eliminates microbes and is performed by specialised cells such as macrophages. Toll-like receptor 4 (TLR4) is expressed on the surface of macrophages and recognizes Gram-negative bacteria. Moreover, TLR4 has been suggested to play a role in the phagocytosis of Gram-negative bacteria, but the mechanisms remain unclear. Here we have used primary human macrophages and engineered THP-1 monocytes to show that the TLR4 sorting adapter, TRAM, is instrumental for phagocytosis of Escherichia coli as well as Staphylococcus aureus. We find that TRAM forms a complex with Rab11 family interacting protein 2 (FIP2) that is recruited to the phagocytic cups of E. coli. This promotes activation of the actin-regulatory GTPases Rac1 and Cdc42. Our results show that FIP2 guided TRAM recruitment orchestrates actin remodelling and IRF3 activation, two events that are both required for phagocytosis of Gram-negative bacteria.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adaptor Proteins, Signal Transducing / metabolism
Adaptor Proteins, Signal Transducing / physiology*
Animals
Carrier Proteins / metabolism*
Carrier Proteins / physiology
Endocytosis
Endosomes
Escherichia coli / pathogenicity
HEK293 Cells
Humans
Interferon Regulatory Factor-3
Lipopolysaccharides
Macrophages / immunology
Macrophages / metabolism
Membrane Proteins / metabolism*
Membrane Proteins / physiology
Mice
Mice, Inbred C57BL
Myeloid Differentiation Factor 88
Phagocytosis / physiology*
Primary Cell Culture
Protein Transport
Signal Transduction
Staphylococcus aureus / pathogenicity
THP-1 Cells
Toll-Like Receptor 4 / metabolism
cdc42 GTP-Binding Protein
rab GTP-Binding Proteins
rac1 GTP-Binding Protein

Substances

Adaptor Proteins, Signal Transducing
Carrier Proteins
IRF3 protein, human
Interferon Regulatory Factor-3
Lipopolysaccharides
Membrane Proteins
Myeloid Differentiation Factor 88
RAC1 protein, human
TICAM2 protein, human
TLR4 protein, human
Toll-Like Receptor 4
CDC42 protein, human
RAB11FIP2 protein, human
cdc42 GTP-Binding Protein
rab GTP-Binding Proteins
rac1 GTP-Binding Protein

Grants and funding

The Research Committee between St. Olavs Hospital and Faculty of Medicine and Health Science, NTNU,, https://www.ntnu.no/documents/10268/1221071659/Tildeling+av+forskningsmidler+fra+Felles+Forskningsutvalg_rev2015.pdf/15944b9a-115c-48d6-b56f-b2f8e8e855a0sff, awarded the grant # 46082500 to HH, that financed this study. The NTNU’s Onsager Fellowship, https://www.ntnu.edu/research/onsager-fellowship, awarded the grant #80420223 to RKK, that financed this study. The Research Council of Norway through its Centers of Excellence funding scheme, https://www.forskningsradet.no/prognett-sff/Home_page/1224067001813, awarded the grant #223255/F50 to TE, that financed this study. The Research Council of Norway, FRIMEDBIO program,, file:///Users/haraldhu/Downloads/NyeprosjekterFRIMEDBIO2017NorskogEngelsk-2.pdf, awarded the grant # 275876 to TE, that financed this study. The Liaison Committee for education, research and innovation in Central Norway,, https://helse-midt.no/samarbeidsorganetfelles forskingsutvalg, awarded the grant # 50052400 to TE, that financed this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.